List from citations of TREOR, DICVOL, FOX, TOPAS, EXPO, EXTRA, LBM, etc, etc, etc 2007-1 Burley, JC Motherwell, WDS Maaranen, J Ringwald, M Dichloro[(eta(5)-cyclopentadienyl)dimethyl(eta(5)-3-phenylindenyl)silane ]hafnium(IV): a powder study ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 63, 2007, M238-M240. The title compound, [Hf(C22H20Si)Cl-2], was solved by simulated annealing from laboratory X-ray powder diffraction data collected at room temperature. The molecular structure comprises a hafnium dichloride centre, coordinated by a eta(5)-cyclopentadienyl and a eta(5)-3-phenylindenyl unit, which are connected through a shared dimethylsilicon linkage. 2007-2 2006-1 Fukuda, K Hasegawa, H Iwata, T Hashimoto, S Crystal structure of calcium cobalt orthophosphate, CaCo[Ca0.1Co0.9](PO4)(2) POWDER DIFFRACTION 21, 2006,220-224 Ca1.1Co1.9(PO4)(2) , P2(1)/n, Z = 4 laboratory X-ray powder diffraction data (Co K alpha) using direct methods and the Rietveld refinement. TREOR 2006-2 Henry, N Mentre, O Abraham, F MacLean, EJ Roussel, P Polycationic disorder in [Bi6O4(OH)(4)](NO3)(6): Structure determination using synchrotron radiation and microcrystal X-ray diffraction JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3087-3094 bismuth basic nitrate [Bi6O4(OH)(4)(NO3)(6) rhombohedral hexagonal unit cell , Z = 6, space group R-3. determined at 150(2) K by synchrotron X-ray TREOR 2006-3 Pan, ZG Xu, MC Cheung, EY Platts, JA Harris, KDM Constable, EC Housecroft, CE Solid-state structural properties of 2,4,6-trimethoxybenzene derivatives, determined directly from powder X-ray diffraction data in conjunction with other techniques JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3214-3223 2,4,6-trimethoxybenzaldehyde, 2,4,6-trimethoxybenzyl alcohol, 2,4,6-trimethoxyacetophenone powder X-ray diffraction data, direct-space Genetic Algorithm (GA) technique for structure solution followed by Rietveld refinement. TREOR 2006-4 Kahlenberg, V Kaindl, R Tobbens, DM The crystal structure of the interrupted framework silicate K9.6Ca1.2Si12O30 determined from laboratory X-ray diffraction data JOURNAL OF SOLID STATE CHEMISTRY, 179, 2006, 1948-1956. potassium calcium silicate K9.6Ca1.2Si12O30 (or K8CaSi10O25) direct methods aided by distance least squares optimization laboratory X-ray powder diffraction data. R3c Z = 3, TREOR/DICVOL 2006-5 ?? Zhizhin, MG Pounds, HA Spiridonov, FM Komissarova, LN Dorhout, PK Characterization and structural determination of a new sodium lanthanum phosphate thiosulfate, Na2La[PO4][S2O3] JOURNAL OF ALLOYS AND COMPOUNDS, 418, 2006, 90-94. Na2La[PO4]S2O3]. Z = 4 in the space group P2(1)/c. The crystal structure was determined using a Rietveld analysis of the powder diffraction data. TREOR 2006-8 Lasocha, W Rafalska-Lasocha, A Synthesis and X-ray crystal structure investigations of the complexes of a proton sponge with selected inorganic acids: Crystal structure of DMAN.HI complex CRYSTAL RESEARCH AND TECHNOLOGY, 41, 2006, 588-594. 1,8-bis(dimethylamino)naphthalene.HI P2(1)/c TREOR 2006-9 Platteau, C Lefebvre, J Hemon, S Affouard, F Willart, JF Derollez, P Ab initio structure determination of two anhydrous forms of alpha-lactose by powder X-ray diffraction ZEITSCHRIFT FUR KRISTALLOGRAPHIE Part 2, Suppl 23 (2006) 595-600. stable form of alpha-lactose is triclinic P1, Z = 2, hygroscopic anhydrous alpha-lactose, P21, Z = 2. The starting structural models were found by a Monte-Carlo simulated annealing method. The final structures were obtained through Rietveld refinements with soft restraints on interatomic bond lengths and bond angles and crystalline energy minimisation to locate the H atoms of the hydroxyl groups. TREOR 2006-10 Wolcyrz, M Paciak, M Kowalczyk, J Maciejewski, M Crystal structure of silver salicylate C7H5AgO3 solved by reverse Monte-Carlo method from X-ray powder diffraction data and confirmed on single crystal ZEITSCHRIFT FUR KRISTALLOGRAPHIE, 221, 2006, 270-275. silver salicylate C7H5AgO3 solved originally on powder sample by molecular modeling and reverse Monte-Carlo (RMC) algorithm and then confirmed by X-ray diffraction single crystal structure solution and refinement. P2(1)/n) laboratory X-ray sources. TREOR 2006-11 ?? Tamura, R Mizuta, M Yabunaka, S Fujimoto, D Ariga, T Okuhara, S Ikuma, N Takahashi, H Tsue, H Induction and inhibition of preferential enrichment by controlling the mode of the polymorphic transition with seed crystals SO CHEMISTRY-A EUROPEAN JOURNAL 12, 2006, 3515-3527. CHOLESTEROL MONOHYDRATE direct-space approach employing the Monte Carlo method with the Rietveld refinement for the structure solution from the powder X-ray diffraction data. TREOR 2006-12 ?? Zucca, A Petretto, GL Stoccoro, S Cinellu, MA Minghetti, G Manassero, M Manassero, C Male, L Albinati, A Dinuclear C,N,C cyclometalated platinum derivatives with bridging delocalized ligands. Fourfold deprotonation of 6,6 '-diphenyl-2,2 '-bipyridine, H4L, promoted by "Pt(R)(2)" fragments (R = Me, Ph). Crystal structures of [Pt-2(L)(3,5-Me(2)py)(2)] and {Pt-2(L)(dppe)}(2) (dppe=1,2-bis(diphenylphosphino)ethane). X-ray powder diffraction of [Pt-2(L)(CO)(2)] ORGANOMETALLICS 25, 2006, 2253-2265. a powder X-ray diffraction analysis has been performed on complex [Pt-2(L)(CO)(2)]. TREOR 2006-12 Guo, F Cheung, EY Harris, KDM Pedireddi, VR Contrasting solid-state structures of trithiocyanuric acid and cyanuric acid CRYSTAL GROWTH & DESIGN 6, 2006, 846-848. trithiocyanuric acid (TTCA) structure determination directly from powder X-ray diffraction data, using the direct-space genetic algorithm technique for structure solution followed by Rietveld refinement. TREOR 2006-13 Mondal, S Mukherjee, M Chakraborty, S Mukherjee, AK A novel three-dimensional network containing Pr(III) ions and tartrate: Synthesis, spectroscopic, thermal, ab initio X-ray powder structure analyses, and photoluminescence properties CRYSTAL GROWTH & DESIGN 6, 2006, 940-945. praseodymium tartrate [Pr(C4H4O6)(C4H5O6)(H2O)] P2(1)2(1)2(1), and Z = 4. The crystal structure has been solved from laboratory X-ray powder diffraction data using a direct space global optimization technique and refined by the Rietveld method. TREOR, DICVOL, 2006-14 Guo, F Casadesus, M Cheung, EY Coogan, MP Harris, KDM On the spontaneous induction of chirality in the preparation of Werner's complex cis-[CoBr(NH3)(en)(2)]Br-2 CHEMICAL COMMUNICATIONS issue 17, 2006, 1854-1856. cis-[CoBr(NH3)(en)(2)]Br-2 structure determination from powder X-ray diffraction data, TREOR, N-TREOR, 2006-15 Albov, DV Jassem, A Kuznetsov, AI An independent refinement of H-atom coordinates from laboratory X-ray powder data in tetraformaltrisazine ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006, O1449-O1451. ID PROGRAM tetraformaltrisazine (systematic name: 1,2,3,4,5,6,7,8-octahydro-1,2,4,5-tetrazino-[1,2-a][1,2,4,5]tetrazine), C4H12N6, has been solved by simulated annealing from X-ray laboratory powder data and refined by Rietveld refinement without any restraints for non-H atoms. TREOR 2006-16 ?? Katz, MJ Aguiar, PM Batchelor, RJ Bokov, AA Ye, ZG Kroeker, S Leznoff, DB Structure and multinuclear solid-state NMR of a highly birefringent lead-gold cyanide coordination polymer JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 3669-3676. microcrystalline Pb[Au(CN)(2)](2) (2). a structure is proposed on the basis of the NMR and X-ray powder data, TREOR 2006-17 Stowasser, F Renkenberger, C Ab initio crystal structure determination of Bi6Rh12O29 from powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE, 221, 2006, 206-212 simulated annealing Bi6Rh12O29 C2/m, Z = 4 laboratory X-ray powder diffraction data with the software package TOPAS TREOR 2006-18 Kongshaug, KO Fjellvag, H Design of novel bilayer compounds of the CPO-8 type containing 1D channels INORGANIC CHEMISTRY 45, 2006, 2424-2429. CPO-8-BPY ([Zn(C8H5NO4)(ClOH8N2)(0.5)] . 3nH(2)O), CPO-8-DPE ([Zn(C8H5NO4)(Cl2H10N2)(0.5)](n) . 2.5nH(2)O), CPO-8-DPA ([Zn(C8H5NO4)(Cl2H12N2)(0.5)](n) . 2.5nH(2)O), and CPO-8-DPP ([Zn(C8H5NO4)(C13H14N2)(0.5)](n) . 3nH(2)O), The crystal structures of these porous high-temperature variants have been determined on the basis of powder X-ray diffraction data. All of the compounds show preferential adsorption of H-2 over N-2 at 77 K. TREOR 2006-19 Ivashkevich, LS Selevich, KA Lesnikovich, AI Selevich, AF Lyakhov, AS Two isostructural manganese(III) diphosphates, acid alpha-MnHP2O7 and double MnLiP2O7: crystal structure determination from X-ray powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE, 221, 2006, 115-121. Ab initio crystal structure determination of the a form of MnHP2O7 and Rietveld refinement of the MnLiP2O7 structure were performed using powder X-ray diffraction data. TREOR 2006-20 Gomez-Alcantara, MM Aranda, MAG Olivera-Pastor, P Beran, P Garcia-Munoz, JL Cabeza, A Layered and pillared metal carboxyethylphosphonate hybrid compounds DALTON TRANSACTIONS iss 4, 2006, 577-585. carboxyethylphosphonate hybrid materials: Mn-II(O3PCH2CH2COOH)(H2O)-H-. (1), Mn-III(OH)(O3PCH2CH2COOH)(H2O)-H-.(2), solved ab initio from laboratory X-ray powder diffraction data and refined by the Rietveld method. Al-III(OH)(3)(O3PCH2CH2CO2)(2)(.)3H(2)O (3) solved ab initio from synchrotron X-ray powder diffraction data. TREOR 2006-21 Larranaga, A Mesa, JL Pizarro, JL Pena, A Olazcuaga, R Arriortua, MI Rojo, T Synthesis and structural, spectroscopic and magnetic studies of two new polymorphs of Mn(SeO3) . H2O JOURNAL OF SOLID STATE CHEMISTRY Mn(SeO3) H2O solved from X-ray powder diffraction data. TREOR 2006-22 Vigo, L Risto, M Jahr, EM Bajorek, T Oilunkaniemi, R Laitinen, RS Lahtinen, M Ahlgren, M Isomerism in [MCl2(ERR ')(2)] (M = Pd, Pt; E = S, Se; R, R ' = Me, Ph) CRYSTAL GROWTH & DESIGN 6, 2006, 2376-2383. A series of thioether and selenoether complexes [MCl2(EPh2)(2)] and [MCl2(SMePh)(2)] (M = Pt, Pd; E = S, Se) have been prepared and characterized to explore the isomerism of the complexes in solution and in the solid state. The NMR spectroscopic information indicates that only one isomer is present in solution in case of the palladium complexes, while two isomers are formed in the case of most platinum complexes. Single-crystal X-ray structures of trans-[PdCl2(SPh2)(2)] (1t), trans-[PdCl2(SePh2)(2)] (2t), cis-[PtCl2(SePh2)(2)] (4c), trans-[PdCl2(SMePh)(2)] ( 5t), and trans-[PtCl2(SMePh)(2)] ( 7t) are reported and have been used as starting points for the X-ray powder diffraction structure determinations using simulated annealing method together with Rietveld refinement of the powder diffraction data. The presence of only trans- isomers in the solid phases was deduced in the case of [PdCl2(SPh2)(2)] and [PdCl2(SePh2)(2)] (1t and 2t, respectively). By contrast, the Rietveld refinement of the powder X-ray diffraction diagrams of [PtCl2(SPh2)(2)] and [PtCl2(SePh2)(2)] indicated the presence of both trans- and cis-isomers (3t, 3c and 4t, 4c, respectively) with mixing ratios that are consistent with NMR spectroscopic information in solution. The density functional theory calculations using [MCl2(EMe2)(2)] as model complexes indicated that while the trans- isomers of the palladium complexes lie at significantly lower energy than the cis-isomers do, in the case of the platinum complexes the energy difference is smaller and decreases, as the chalcogen atom of the chalcogenoether ligand becomes heavier. DICVOL 2006-23 Hulme, AT Fernandes, P Florence, A Johnston, A Shankland, K Powder study of 3-azabicyclo[3.3.1]nonane-2,4-dione 1-methylnaphthalene hemisolvate ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006, O3752-O3754. The crystal structure of the title compound, C8H11N1O2.-0.5C(11)H(10), was solved by simulated annealing from laboratory X-ray powder diffraction data, collected at room temperature. Subsequent Rietveld refinement, using data collected to 1.51 angstrom resolution, yielded an R-wp value of 0.057. The compound crystallizes with two molecules of 3-azabicyclononane-2,4- dione and one molecule of 1-methylnaphthalene in the asymmetric unit. DICVOL 2006-24 Llinas, A Fabian, L Burley, JC van de Streek, J Goodman, JM Amodiaquinium dichloride dihydrate from laboratory powder diffraction data ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006, O4196-O4199. The title compound (systematic name: {5-[(7-chloroquinolinium4-yl) amino]-2-hydroxybenzyl} dimethylammonium dichloride dihydrate), C20H24ClN3O2+ . 2Cl (- .) 2H(2)O, has one amodiaquinium dication, two Cl- anions and two water molecules in the asymmetric unit. The crystal structure was solved by simulated annealing from laboratory X-ray powder diffraction data, with data collected at room temperature. Rietveld refinement of this model led to a final R-wp of 0.047 to 1.79 angstrom resolution. A three-dimensional network of hydrogen bonding links the amodiaquinium cations via water molecules and Cl- ions. DICVOL 2006-25 Martinetto, P Terech, P Grand, A Ramasseul, R Dooryhee, E Anne, M Molecular structure of a D-homoandrostanyl steroid derivative: Single crystal and powder diffraction analyses JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 15127-15133. The knowledge of the structure of a molecular crystal is frequently a prerequisite for the understanding of its solid state properties. Even though single-crystal diffractometry is the method of choice when it comes to crystal structure determination, methods using powder diffraction data become more and more competitive. There has been much recent interest in the development of a new generation of "direct-space" approaches that are particularly suited for molecular crystals. The crystallographic structure of a steroid derivative molecule (17,17-di-n-propyl-17a-aza-D-homo-5R-androstan-3,-ol) was obtained in two independent ways: from a single crystal by laboratory X-rays and from a polycrystalline powder by high-resolution synchrotron powder diffraction. The molecule crystallizes in the orthorhombic space group P2(1)2(1)2(1) (a) 6.5346, b) 17.6006 and c) 19.6978 angstrom). Hydrogen bonds form infinite chains of molecules parallel to the c axis. DICVOL 2006-26 ?? Kubota, Y Takata, M Matsuda, R Kitaura, R Kitagawa, S Kobayashi, TC Metastable sorption state of a metal-organic porous material determined by in situ synchrotron powder diffraction ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45, 2006, 4932-4936. DICVOL 2006-27 Duc, F Gonthier, S Brunelli, M Trombe, JC Hydrothermal synthesis and structure determination of the new vanadium molybdenum mixed oxide V1.1Mo0.9O5 from synchrotron X-ray powder diffraction data JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3591-3598. AB A new vanadium molybdenum mixed oxide V1.1Mo0.9O5 [V(V)(0.2)V(IV)(0.9)Mo(VI)(0.9)O-5] has been synthesized, as a pure phase, via hydrothermal methods in the presence of molybdic acid and vanadyl sulfate. Its crystal structure has been solved ab initio from high-resolution powder diffraction data collected at the ESRF beamline ID31. This compound crystallizes in the monoclinic symmetry, space group C2/m, with cell dimensions a = 12.1230(2) angstrom, b = 3.7168(1) angstrom, c = 4.0336(1) angstrom, beta = 90.625(3)degrees and Z = 2 per formula. The structure consists of double strings of VO5 square pyramids sharing edges and corners along [ 100] and [0 10], and more weakly bound along [001]. In this latter direction, the bond (V,Mo)-O = 2.377 angstrom, while remaining long, leads for the first time to the interpenetration of the apical oxygens of the [(V,MO)(2)O-5](n) layers, resulting in a three-dimensional (3D) structure closely related to R-Nb2O5. This structure will be compared to the pure layer structure of V2O5 where this bond reaches 2.793 angstrom. N-TREOR 2006-28 Hernandez, O Knight, KS Van Beek, W Boucekkine, A Boudjada, A PauluS, W Meinnel, J Phases II and IV of 1,3,5-trichloro-2,4,6-trimethylbenzene: Ab initio crystal structure determination by high-resolution powder diffraction JOURNAL OF MOLECULAR STRUCTURE 791, 2006, 41-52. The hitherto unknown structures of stable crystal phases 11 and IV of undeuterated 1,3,5-trichioro-2,4,6-trimethylbenzene, TCM9H (phase 11, above T-III -> II= 314 K, and phase IV, below T-III -> IV similar or equal to 160 K, phase III in between) have been solved ab initio from powder synchrotron X-ray diffraction data, respectively, at 343 K by direct methods and at 50 K using a Monte-Carlo simulated annealing method. They have been then refined for perdeuterated TCM (TCM9D, same behaviour as TCM9H) against high-resolution powder neutron diffraction data at 343 and 2 K, respectively. Phase 11 is disordered (space group P2(1)/n, Z= 2, a = 15.12984(13) angstrom, b = 3.92080(3) angstrom, c = 8.27786(8) angstrom, beta = 90.8374(8)degrees), whilst phase IV is ordered (space group P (1) over bar, Z= 2, a = 7.42872(5) angstrom, b = 8.75731(6) angstrom, c = 8.76246(6) A, alpha = 59.8543(4)degrees, beta = 68.2959(5)degrees, gamma = 73.1654(6)degrees). The mechanisms driving both reconstructive phase transitions at T-III -> II and T-III -> IV are described at a microscopic level; it is shown that they involve rotations of the molecules (out-of-plane and in-plane, respectively, with regard to the molecular plane of phase 111) leading to huge atomic displacements up to 2.0 and 1.2 angstrom, respectively. The molecular conformation in phase IV is compared to the one obtained from DFT quantum chemistry calculations for an isolated molecule in order to extract the characteristics of the inter-molecular interactions and the deuteron nuclear densities are extracted at 2 K. DICVOL 2006-29 Serre, C Millange, F Devic, T Audebrand, N Van Beek, W Synthesis and structure determination of new open-framework chromium carboxylate MIL-105 or Cr-III(OH) . {O2C-C-6(CH3)(4)-CO2}center dot nH(2)O MATERIALS RESEARCH BULLETIN 41, 2006, 1550-1557. Two new three-dimensional chromium(III) dicarboxylate, MIL-105 or Cr-III(OH) . {O2C-C-6(CH3)(4)-CO2} . nH(2)O, have been obtained under hydrothermal conditions, and their structures solved using X-ray powder diffraction data. Both solids are structural analogs of the known Cr benzenedicarboxylate compound (MIL-53). Both contain trans corner-sharing CrO4(OH)(2) octahedral chains connected by tetramethylterephthalate di-anions. Each chain is linked by the ligands to four other chains to form a three-dimensional framework with an array of 1D pores channels. The pores of the high temperature form of the solid, MIL-105ht, are empty. However, MIL-105ht re-hydrates at room temperature to finally give MIL-1051t with pores channels filled with free water molecules (It: low temperature form; ht: high temperature form). The thermal behaviour of the two solids has been investigated using TGA. Crystal data for MIL-105ht: monoclinic space group C2/c with a = 19.653(1) angstrom, b = 9.984(1) angstrom, c = 6.970(1) angstrom, beta = 110.67(1)degrees and Z = 4. Crystal data for MIL-1051t: orthorhombic space group Pnam with a = 17.892(1) angstrom, b = 11. 165(1) angstrom, c = 6.916(1) angstrom and Z = 4. DICVOL 2006-30 Ibberson, RM The low-temperature phase III structure and phase transition behaviour of cyclohexanone ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 592-598. The crystal structure of phase III of perdeuterocyclohexanone, C6D10O, has been determined at 5 K using high-resolution neutron powder diffraction. Below its melting point of 245 K cyclohexanone forms a plastic crystal in the space group Fm (3) over barm. On cooling below 225 K the crystal transforms to the monoclinic phase III structure in the space group P2(1)/n. The orthorhombic phase II structure exists under high pressure, but the triple point for all three phases is close to atmospheric pressure. Details of the phase II structure are also reported at 4.8 kbar (273 K) and ambient pressure. The phase behaviour of the compound and isotope effects are discussed. DICVOL 2006-31 Mora, AJ Brunelli, M Fitch, AN Wright, J Baez, ME Lopez-Carrasquero, F Structures of (S)-(-)-4-oxo-2-azetidinecarboxylic acid and 3-azetidinecarboxylic acid from powder synchrotron diffraction data ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 606-611. The crystal structures of the four-membered heterocycles (S)(-)-4-oxo-2-azetidinecarboxylic acid (I) and 3-azetidinecarboxylic acid (II) were solved by direct methods using powder synchrotron X-ray diffraction data. The asymmetry of the oxoazetidine and azetidine rings is discussed, along with the hydrogen bonding. DICVOL 2006-32 Damay, F Carretero-Genevrier, A Cousson, A Van Beek, W Rodriguez-Carvajal, J Fillaux, F Synchrotron and neutron diffraction study of 4-methylpyridine-N-oxide at low temperature ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 627-633. The structure of 4-methylpyridine-N-oxide has been determined at 250, 100 and 10 K by combined synchrotron (C6H7NO) and neutron (C6D7NO) powder diffraction experiments. At 250 K the space group is I4(1)/amd and the tetragonal unit cell [a = b = 7.941 (2), c = 19.600 (5) angstrom] contains eight equivalent molecules. At 100 K the structure is orthorhombic, with space group Fddd, a = 12.138 (2), b = 10.237 (2) and c = 19.568 (3) angstrom. The 16 equivalent molecules are rotated by about 8 degrees around the c axis with respect to positions at high temperature. At 10 K the best structural model corresponds to a tetragonal unit cell with the space group P4(1), a = b = 15.410 (2) angstrom and c = 19.680 (3) angstrom. The 32 molecules (eight molecules in the asymmetric unit) show complex reorientations around the three cell axes. Whereas at 250 and 100 K the deuterated methyl groups are largely disordered, at 10 K they are ordered in-phase along infinite chains parallel to a and b. Face-to-face methyl groups along c are in an eclipsed configuration. The structure at 10 K suggests that the manifold of rotational tunnelling transitions could be due to inequivalent lattice sites for crystallographically independent methyl groups. DICVOL 2006-33 Hulme, AT Fernandes, P Florence, A Johnston, A Shankland, K Powder study of 3-azabicyclo[3.3.1]nonane-2,4-dione form 2 ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006, O3046-O3048. A polycrystalline sample of a new polymorph of the title compound, C8H11NO2, was produced during a variable-temperature X-ray powder diffraction study. The crystal structure was solved at 1.67 angstrom resolution by simulated annealing from laboratory powder data collected at 250 K. Subsequent Rietveld refinement yielded an R-wp of 0.070 to 1.54 angstrom resolution. The structure contains two molecules in the asymmetric unit, which form a C 2 2(8) chain motif via N-H . . . O hydrogen bonds. DICVOL 2006-34 Cerny, R Renaudin, G Tokaychuk, Y Favre-Nicolin, V Complex intermetallic compounds in the Mg-Ir system solved by powder diffraction ZEITSCHRIFT FUR KRISTALLOGRAPHIE Suppl. 23, part 2, 2006, 411-416. The crystal structures of two new topologically close-packed intermetallic compounds, MgIr (Cmca, 25 atoms) and Mg2-xIr3+x (x=0.067, C2/m, 11 atoms) were fully characterized by high resolution synchrotron powder diffraction and global optimization of a structural model in direct space. The simulated annealing algorithm (in parallel tempering mode) and computer program Fox were used. DICVOL, FOX 2006-35 Akkari, H Benard-Rocherulle, P Merazig, H Roisnel, T Rocherulle, J Hydrothermal synthesis, crystal structure and thermal behaviour of the first lanthanide sulfato-squarate, La-2(H2O)(4)(SO4)(2)(C4O4) SOLID STATE SCIENCES 8, 2006, 704-715. A new three-dimensional lanthanum(III) sulfate squarate, La-2(H2O)(4)(SO4)(2)(C4O4), has been synthesized hydrothermally with squaric acid at 180 degrees C and its structure has been solved by single-crystal X-ray diffraction methods. A relevant feature of this new material is that it constitutes the first member of a family of hybrids based on this composition. It crystallizes in the monoclinic space group P(2)1/n, with a = 6.5965(1) angstrom, b = 10.9595(3) angstrom, c = 9.6633(2) angstrom, beta = 96.457(1)degrees, V = 694.17(3) angstrom(3), Z = 2. Its framework is built up from dimers of O-O edged-sharing nine-coordinated LaO7(H2O)(2) polyhedra described as monocapped square antiprisms. The linking of the binuclear La species by sulfate groups occurs in planes parallel to (11(1) over bar) and subsequently generates inorganic layers showing cavities. The stacking of them along the a-axis generates tunnels filled with bonded water molecules and squarate moieties. The three-dimensionality is ensured by one sulfate oxygen atom and the C-4-cycles. Thus, according to this structural description, the material presents a novel 3D-type structure in the field of the mixed anionic lanthanide compounds. The thermal behavior of La-2(H2O)(4)(SO4)(2)(C4O4) has been investigated using TG-DTA and X-ray thermodiffractometry showing that this precursor of crystallized lanthanum oxide at 900 degrees C is stable up to 150 degrees C. DICVOL 2006-36 Barrio, M Pardo, LC Tamarit, JL Negrier, P Salud, J Lopez, DO Mondieig, D Two-component system CCl4 + (CH3)(3)CBr: Extrema in equilibria involving orientationally disordered phases JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 12096-12103. Phase equilibria involving orientationally disordered (OD) and liquid phases of the two-component system between carbon tetrachloride (CCl4) and 2-methyl-2-bromomethane ((CH3)(3)CBr) have been determined by means of X-ray powder diffraction and thermal analysis techniques from 210 K up to the liquid state. The isomorphism relation between the OD stable face-centered cubic (FCC) phase of (CH3)(3)CBr and the metastable FCC phase of CCl4 has been demonstrated throughout the continuous evolution of the lattice parameters and the existence of the two-phase equilibrium [FCC + L] for the whole range of composition, despite the monotropy of the FCC phase for the CCl4 component with respect to its OD rhombohedral (R) stable phase. A continuous series of OD R mixed crystals is found, which confirms the R lattice symmetry of the OD phase II of (CH3)(3)CBr, for which the crystallographic results have been long-time misinterpreted. X-ray patterns of such a phase were indexed according to the recent single-crystal results obtained by Rudman (Rudman, R. J. Mol. Struct. 2001, 569, 157). In addition, some experimental evidences are given to confirm the number of molecules per unit cell (Z = 21). The thermodynamic assessment reproduces coherently the phase diagram for the stable [R + L] and [R + FCC] two-phase equilibria as well as for the partially metastable [FCC + L] two-phase equilibrium and provides a set of data for the thermodynamic properties of nonexperimentally available phase transitions of pure components. Surprisingly, the phase equilibrium involving R and FCC OD phases appears as one of the very few showing a solid-solid equilibrium with two extremes. DICVOL 2006-37 Ibberson, RM Yamamuro, O Tsukushi, I The crystal structures and phase behaviour of cyclohexene oxide CHEMICAL PHYSICS LETTERS 423, 2006, 454-458. The phase 11 crystal structure of perdeuterated cyclohexene oxide has been solved from neutron powder diffraction data at 5 K utilising a simulated annealing method. The structure is triclinic, space group P1, with a unit cell volume of 268 angstrom(3). The refined molecular conformation is shown to be in close agreement with recent ab initio calculations. The p-T phase diagram determined using DTA and details of the phase I structure are also reported. DICVOL 2006-38 Fernandes, P Florence, AJ Shankland, K Shankland, N Johnston, A Powder study of chlorothiazide N,N-dimethyl-formamide solvate ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006, O2216-O2218 The crystal structure of the title compound [systematic name: 6-chloro-4H-1,2,4-benzothia-diazine-7-sulfonamide 1,1-di-oxide-N,N-dimethylformamide (1/1)], C7H6ClN3O4S2.C3H7NO, was solved by simulated annealing from laboratory X-ray powder diffraction data collected at 100 K. Subsequent Rietveld refinement, using data collected to 1.5 angstrom resolution, yielded an R-wp of 0.050. Hydrogen bonds to N,N-dimethylformamide form the rungs of a ladder motif, which is further stabilized by a pi(...)halogen dimer interaction. The benzene rings in adjacent ladders engage with each other in an offset face-to-face pi-pi interaction. DICVOL 2006-39 Tokaychuk, YO Filinchuk, YE Fedorchuk, AO Kozlov, AY Mokra, IR New representatives of the linear structure series containing empty Ga/Ge cubes in the Sm-Ga-Ge system JOURNAL OF SOLID STATE CHEMISTRY, 179, 2006, 1323-1329. New ternary intermetallic compounds Sm2Ga7-xGex (x = 5.2-6.1) and Sm4Ga11-xGex (x = 5.76-8.75) were synthesized and their crystal structures were determined by X-ray powder diffraction at compositions Sm2Ga1.8Ge5.2 and Sm4Ga5.24Ge5.76, Sm2Ga1.8Ge5.2 crystallizes with the Ce-2(Ga0.1Ge0.9)(7) type of structure (space group Cmce, Pearson code oS80-8.00, a = 8.46216(13), b = 8.15343(13) b = 21.1243(3) angstrom, Z = 8), while Sm4Ga5.24Ge5.76 exhibits a new structure (space group Cmmm. Pearson code oS52-22.00. a = 4.21038(4). b = 35.8075(3), c = 4.14023(4) angstrom, Z = 2). Both structures are the members of the linear intergrowth structure series built up from segments of BaAl4. AlB2 and alpha-Po structure types. Their Ga/Ge networks contain characteristic empty cubes with one side capped by an atom subjected to an intrinsic displacive disorder. A model of Ga/Ge localization was suggested the basis of crystal-chemical analysis. DICVOL 2006-40 Surble, S Serre, C Millange, F Ferey, G Structural changes upon dehydration of Pr-(III)(H2O){C6H3-(CO2)(3)} or MIL-81: A new three-dimensional praseodymium 1,2,4-benzenetricarboxylate with a one dimensional inorganic sub-network SOLID STATE SCIENCES 8, 2006, 413-417. A new three-dimensional lanthanide(III) tricarboxylate, MIL-81(1) or Pr-(III)(H2O)(C6H3-(CO2)(3)) has been obtained under hydrothermal conditions. Its three-dimensional structure, which has been determined using X-ray powder diffraction data, is built-up from edge-sharing chains of nine coordinated prascodymium(III) capped square antiprisms linked through 1,2,4-Benzenetricarboxylate (1,2,4-BTC) moieties. Its thermal behaviour has been investigated using TGA and X-ray thermodiffractometry and reveals that dehydration is followed by an irreversible structural change giving the solid MIL-81ht or Pr-(III)(C6H3-(CO2)(3)) with both a change in the environment of the rare earth and in the connection mode of the carboxylate. Crystal data for MIL-81: monoclinic space group P2(1) with a = 10.272(1) angstrom, b = 7.057(l) angstrom, c = 6.232(1) angstrom, c= 93.668(4)degrees and Z = 2. Crystal data for MIL-81ht: triclinic space group P-1 with a = 9.864(1) angstrom, b = 7.054(1) angstrom, C = 5.784(1) angstrom, alpha = 90.862(9)degrees,beta = 92.439(6)degrees, gamma = 91.594(8)degrees and Z = 2. DICVOL 2006-41 Wu, L Chen, XL Zhang, Y Kong, YF Xu, JJ Xu, YP Ab initio structure determination of novel borate NaSrBO3 JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 1219-1224. A novel orthoborate, NaSrBO3, has been Successfully synthesized by standard solid-state reaction, and the crystal structure has been determined from powder X-ray diffraction data. It crystallizes in the monoclinic space group P2(1)/c with lattice parameters: a = 5.32446(7) angstrom, b = 9.2684(l) angstrom, 6.06683(8) angstrom, beta = 100.589(l)degrees. The fundamental building units are isolated BO3 groups, which are parallelly distributed along two different directions. Because of the anisotropic polarizations of planar BO3 groups, a considerable birefringence can be expected in it. The Na atoms are six-coordinated with O atoms to form octahedra, and the Sr atoms are nine-coordinated, forming tri-capped trigonal prisms. Those polyhedra connect with each other by bridging-oxygen atoms, forming infinite three-dimensional network, which indicates that the cleaving problem is expected to be overcome during the Course of single-crystal growth. The infrared spectrum has been measured, and the result is consistent with the crystallographic study. Moreover, a comparison of the new structure type with the other known orthoborates is presented here. DICVOL 2006-42 Wu, L Chen, XL Xu, YP Sun, YP Structure determination and relative properties of novel noncentrosym metric borates MM '(4)(BO3)(3) (M = Na, M ' = Ca and M = K, M ' = Ca, Sr) INORGANIC CHEMISTRY 45, 2006, 3042-3047. A series of novel noncentrosymmetric borates, MM'(4)(BO3)(3) (M = Na, M' = Ca; M = K, M' = Ca, Sr), have been successfully synthesized via a standard solid-state reaction. The crystal structures have been determined by the SDPD (structure determination from powder diffraction) method. They crystallize in the noncentrosymmetric space group Ama2 with the following lattice parameters: a = 10.68004(11) angstrom, b = 1 1.28574(11) angstrom, c = 6.48521(6) angstrom for NaCa4(BO3)(3); a = 10.63455(10) angstrom, b = 11,51705(11) angstrom, c = 6.51942(6) angstrom for KCa4(BO3)(3); and a = 11.03843(8) angstrom, b = 11.98974(9) angstrom, c = 6.88446(5) angstrom for KSr4(BO3)(3). The fundamental building units are isolated BO3 anionic groups. Their second harmonic generation (SHG) coefficients were one-half (NaCa4(BO3)(3)), one-third (KCa4(BO3)(3)), and two-thirds (KSr4(BO3)(3)) as large as that of KH2PO4 (KDP). The infrared and UV-vis spectra of the three compounds are discussed. Moreover, a comparison of the structures of these novel compounds and three other novel cubic compounds with the same formula, MM'(4)(BO3)(3) (M = Li, M' = Sr; M = Na, M' = Sr, Ba), is presented here. DICVOL 2006-43 Serre, C Groves, JA Lightfoot, P Slawin, AMZ Wright, PA Stock, N Bein, T Haouas, M Taulelle, F Ferey, G Synthesis, structure and properties of related microporous N,N '-piperazinebismethylenephosphonates of aluminum and titanium CHEMISTRY OF MATERIALS 18, 2006, 1451-1457. A porous framework titanium(IV) N,N'-piperazinebis (methylenephosphonate) (MIL-91(Ti)) and its aluminum analogue have been prepared under hydrothermal conditions (MIL = Material Institut Lavoisier). The structure of the aluminum analogue, AlOH(H2L) . nH(2)O (eta similar to 3, L = O3P-CH2-NC4H8N-CH(2)Z, PO3) was solved from a small single crystal and refined against laboratory powder X-ray diffraction data. The structure of the titanium form (TiO(H2L)-nH(2)O (n similar to 4.5)) was determined using the structure of the aluminum form as a starting model and refining it against laboratory X-ray data. Their structures are built up from trans corner-sharing chains of TiO6 or AlO6 octahedra linked together in two directions via the diphosphonate groups. In each case this gives rise to a three-dimensional hybrid network with small channels along the b axis, filled with free water molecules. Thermogravimetric analysis and X-ray thermodiffractometry of the samples reveal that water is lost reversibly below 423 K and that both structures are stable up to 463 K. Dehydration gives porous solids (pore size similar to 3.5 x 4.0 angstrom(2)) which adsorb nitrogen at 77 K to give Langmuir surface areas close to 500 m(2) . g(-1). Crystal data for MIL-91 (Ti) are as follows: space group C2/m. (No. 12) with a = 19.415(2) angstrom, b = 7.071 (1) angstrom, c = 11.483(1) 92.78(1)degrees, V 1574.70(1) angstrom(3), and Z = 2. Crystal Data for MIL-91 (Al) are as follows: space group C2/m (No. 12) With a = 18.947(2) angstrom, b = 6.915(1) angstrom, c = 11.295(1) angstrom, beta = 90.45(1)degrees, and V = 1479.90(1)angstrom(3). DICVOL 2006-44 Hemono, N Rocherulle, J Le Floch, M Bureau, B Synthesis, characterization and devitrification behaviour of an yttrium containing boroaluminate glass JOURNAL OF MATERIALS SCIENCE 41, 2006, 445-453. The glass forming region in the B2O3-Al2O3-Y2O3 composition diagram has been determined by a melting and quenching procedure at temperatures up to 1800 degrees C. Different physical characteristics (density, coefficient of thermal expansion, glass transition and crystallization peak temperatures) have been determined for a 35B(2)O(3)-40Al(2)O(3)-25Y(2)O(3) glass composition (in mot.%). By using a predictive model and some NMR structural data, different elastic moduli (Young's modulus, bulk modulus, shear modulus and Poisson's ratio) have been calculated. The devitrification behaviour has also been studied. Internal crystallization is the dominant mechanism and a new (Y, Al)BO3 ternary phase has been characterized by X-ray powder diffraction. The temperature and time nucleation dependence have been determined from DTA experiments as well as the crystallization kinetics (i.e. the Avrami exponent and the activation energy for crystal growth). DICVOL 2006-45 Ibberson, RM Telling, MTF Parsons, S Structure determination and phase transition behaviour of dimethyl sulfate ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 280-286. The crystal structures of phase I and phase II of dimethyl sulfate, (CH3O)(2)SO2, have been determined using complementary high-resolution neutron powder and single-crystal X-ray diffraction techniques. Below its melting point of 241 K dimethyl sulfate crystallizes in an orthorhombic structure (I) in the space group Fdd2. On cooling below similar to 175 K the crystal transforms to a monoclinic structure ( II) in the space group I2/a. The molecule is located on a twofold axis (Z' = 1/2) in both structures. The phase transition is of first order with strong hysteresis. The phase transition results in changes to both the intra- and the intermolecular coordination environment. DICVOL 2006-46 Haynes, DA Van de Streek, J Burley, JC Jones, W Motherwell, WDS Pamoic acid determined from powder diffraction data ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006, O1170-O1172. The title compound [ systematic name: 4,4'-methylenebis(3-hydroxy-2-naphthoic acid)], C23H16O6, has one half-molecule in the asymmetric unit. The molecular twofold rotational axis about the central C atom is preserved on crystallization. A chain formed by R-2(2)(8) hydrogen bonds runs along the c axis and an intramolecular O-H . . . O=C-OH hydrogen bond is also formed. The crystal structure was solved by simulated annealing from laboratory X-ray powder diffraction data, with data collected at room temperature. Rietveld refinement of this model led to a final R-wp value of 0.0391 at 1.39 angstrom resolution. DICVOL 2006-47 Harper, JK Grant, DM Zhang, YG Lee, PL Von Dreele, R Characterizing challenging microcrystalline solids with solid-state NMR shift tensor and synchrotron X-ray powder diffraction data: Structural analysis of ambuic acid JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 1547-1552. Synchrotron X-ray powder diffraction and solid-state C-13 NMR shift tensor data are combined to provide a unique path to structure in microcrystalline organic solids. Analysis is demonstrated on ambuic acid powder, a widely occurring natural product, to provide the complete crystal structure. The NMR data verify phase purity, specify one molecule per asymmetric unit, and provide an initial structural model including relative stereochemistry and molecular conformation. A refinement of X-ray data from the initial model establishes that ambuic acid crystallizes in the P2(1) space group with unit cell parameters a = 15.5047(7), b = 4.3904(2), and c = 14.1933(4) angstrom and beta = 110.3134(3)degrees. This combined analysis yields structural improvements at two dihedral angles over prior NMR predictions with differences of 103 degrees and 37 degrees found. Only minor differences of +/- 5.5 degrees, on average, are observed at all remaining dihedral angles. Predicted hydroxyl hydrogen-bonding orientations also fit NMR predictions within +/- 6.9 degrees. This refinement corrects chemical shift assignments at two carbons and reduces the NMR error by similar to 16%. This work demonstrates that the combination of long-range order information from synchrotron powder diffraction data together with the accurate shorter range structure given by solid-state NMR measurements is a powerful tool for studying challenging organic solids. DICVOL 2006-48 Burley, JC van de Streek, J Stephens, PW Ampicillin trihydrate from synchrotron powder diffraction data ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 62, 2006, O797-O799. The crystal structure of ampicillin trihydrate {systematic name: 6-[D(-)-alpha-aminophenylacetamido]penicillanic acid trihydrate}, C16H19N3O4S . 3H(2)O, a broad-spectrum beta-lactam antibiotic of the aminopenicillin type, has been determined from synchrotron X-ray powder diffraction data. The three water molecules form an infinite hydrogen-bonded chain through the crystal structure, with hydrogen bonds to the NH3+, COO-, C=O and NH groups of the ampicillin molecules. DICVOL 2006-49 Bowman, A Smith, RI Gregory, DH Synthesis and structure of the ternary and quaternary strontium nitride halides, Sr2N(X, X ') (X, X ' = Cl, Br, I) JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 130-130. A number of new, layered nitride mixed halides have been synthesised in the quaternary phase systems Sr-N-Cl-Br and Sr-N-Br-I. The variation in structure with composition has been investigated by powder X-ray and powder neutron diffraction techniques and the structure of strontium nitride iodide, Sr2NI, has been determined for the first time (rhombohedral space group R-3m, a = 4.0103(1)angstrom, c = 23.1138(2)angstrom, Z = 3). A continuous solid solution exists between Sr2NCl and Sr2NBr with intermediate compounds adopting the same anti-alpha-NaFeO2 structure (rhombohedral space group R-3m) as the ternary end members. A similar smooth and linear relationship between structure and composition is seen from Sr2NBr to Sr2NI and hence cubic close packing of metal-nitrogen layers is adopted regardless of halide, X(X'). While nitride and halide anions occupy distinct crystallographic sites, there is no ordering of the halides in the quaternary materials irrespective of stoichiometry or temperature (between 3 and 673 K). DICVOL 2006-50 Avila-Godoy, R Mora, AJ Acosta-Najarro, DR Delgado, GE Lopez-Rivera, SA Fitch, AN Mora, AE Steeds, JW Structure of the quaternary alloy Zn0.6Mn0.4In2S4 from synchrotron powder diffraction and electron transmission microscopy JOURNAL OF APPLIED CRYSTALLOGRAPHY, 39, 2006, 1-5. The aim of the present work was to determine the structure of the quaternary alloy Zn0.6Mn0.4In2S4 and to locate the Mn2+. This was accomplished by means of powder synchrotron X-ray diffraction, high-resolution microscopy and convergent-beam electron diffraction (CBED). The powder X-ray diffraction pattern was indexed in a rhombohedral cell, with cell constants a = 3.875 (2), c = 37.208 (4) angstrom, and possible space groups R(3) over bar m or R3m. Rietveld refinements using different cationic arrangements in these space groups were performed. A model in space group R3m, in which the tetrahedral and octahedral sites were occupied by different proportions of Zn, Mn and In atoms, gave the best result. The Rietveld refinement of this model led to figures of merit R-wp = 9.8%, R-p = 9.1% and chi(2) = 11.1. Selected-area electron diffraction patterns and high-resolution transmission electron micrographs along [001] reveal the rhombohedral configuration. CBED patterns perpendicular to [001], showing the distinctive 3m symmetry, confirmed space group R3m and the breaking of the centrosymmetry of the parent compound, ZnIn2S4. DICVOL 2006-51 ?? Chotard, JN Filinchuk, Y Revaz, B Yvon, K Isolated [Ni2H7](7-) and [Ni4H12](12-) ions in La2MgNi2H8 ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45, 2006, 7770-7773. 2006-52 ?? Pokhodnya, KI Bonner, M Her, JH Stephens, PW Miller, JS Magnetic ordering (T-c=90 k) observed for layered [Fe-II(TCNE center dot-)(NCMe)(2)](+)[(FeCl4)-Cl-III](-) (TCNE = tetracyanoethylene) JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 15592-15593. 2006-53 Ivashkevich, LS Lyakhov, AS Gaponik, PN Degtyarik, MM Ivashkevich, OA Tiutiunnikov, SI Efimov, VV An X-ray powder investigation of catena-poly[copper(II)-di-mu-chloro-kappa(4)1 : 2Cl-mu-1,5-dimethyl-1H-tetrazole-kappa N-2(3): N-4] ACTA CRYSTALLOGRAPHICA SECTION C 62, 2006, M607-M609. The crystal structure of the polymeric title complex, [CuCl2(C3H6N4)](n), has been solved from laboratory X-ray powder diffraction data collected at room temperature. The structural model obtained was refined with the Rietveld method using geometric soft restraints. There are two Cu atoms, two Cl atoms and one 1,5-dimethyltetrazole ligand in the asymmetric unit. Both Cu atoms lie on inversion centres and adopt essentially elongated octahedral coordination. Within the octahedra, the elongated axial positions are occupied by Cl atoms, while two Cl and two N atoms (N3 and N4 of the tetrazole ring) are in equatorial sites. Each Cl atom forms an asymmetric bridge between neighbouring Cu atoms, which are also bridged via the N3-N4 bond of the tetrazole ring. These bridges result in the formation of polymeric chains, running along the a axis, with weak C H center dot center dot center dot Cl hydrogen bonds crosslinking the chains. 2006-54 Tyutyunnik, AP Zubkov, VG Tarakina, NV Krasil'nikov, VN Perelyaeva, LA Baklanova, IV Svensson, G Synthesis, crystal structure and vibrational spectra of KCrV2O7 and RbCrV2O7 SOLID STATE SCIENCES 8, 2006, 1344-1352. KCrV2O7 and RbCrV2O7 have been synthesized and their crystal structures have been determined using X-ray and neutron powder diffraction techniques. The phases crystallizes in space group P2/c with unit cell parameters for KCrV2O7: a = 7.9526(l) angstrom, b = 4.87543(5) angstrom, c = 6.89 10(1) angstrom and beta =101. 162(1)degrees and RbCrV2O7: a = 8.2361 (1) angstrom, b = 4.89480(4) angstrom, c = 6.8980(l) angstrom and beta = 100.893 (1)degrees. The unit cell was confirmed by selected area electron diffraction studies. The crystal structure consists of two-dimensional CrV2O7- slabs parallel to the (100)-plane, formed from zigzag chains of face- and edge-sharing VO6 octahedra connected through CrO6-octahedra. The VO6 Octahedra are very distorted including a short VO-vanadyl unit. The alkaline metal ions placed in the inter-slab space have coordination number 10+2 forming distorted triangular orthobicupolas. The infrared and Raman spectra of the compounds are presented and discussed. 2006-55 ??? Heines, P Keller, HL Armbruster, M Schwarz, U Tse, J Pressure-induced internal redox reaction of Cs-2[PdI4] center dot I-2, Cs-2[PdBr4] center dot I-2, and Cs-2[PdCl4] center dot I-2 INORGANIC CHEMISTRY 45, 2006, 9818-9825. The pressure-induced redox reaction within the system Cs-2[Pd-2 + I-4], I-2/Cs-2[Pd4+ I-6] was investigated by means of powder X-ray diffraction. Analogous high-pressure X-ray diffraction experiments were performed on the isostructural compounds Cs-2[PdX4]center dot I-2 (X = Cl, Br). Additionally, the phase transition of Cs-2[PdBr4]center dot I-2 to Cs-2[PdBr4I2] was characterized by means of Raman scattering experiments as well as theoretical calculations based on density functional theory. On the basis of experimentally determined crystal structure data, a pathway for the topology of the redox reactions was developed and outlined. 2006-56 Fortes, AD The crystal structure of methanol monohydrate (CD3OD center dot D2O) at 160 K from powder neutron diffraction CHEMICAL PHYSICS LETTERS 431, 2006, 283-288. The structure of methanol monohydrate at 160 K has been solved from powder neutron diffraction data by ab initio methods. The crystal is orthorhombic, space-group Cmc2(1) (Z = 4) with unit cell dimensions a = 4.64910(2) angstrom, b = 14.08464(7) angstrom, c = 4.69358(1) angstrom V = 307.340(2) angstrom(3) (rho(calc) = 1212.29(1) kg m(-3)) at 160 K. The structure consists of water-water chains, linked by ordered hydrogen bonds extending along the c-axis, which cross link methanol-water chains with disordered hydrogen bonds along the a-axis. These perpendicular chains form sheets which are stacked parallel to the b-axis. 2006-57 Nielsen, RKB Kongshaug, KO Fjellvag, H Syntheses, crystal structures and thermal properties of 3D coordination polymers assembled from 1,4,5,8-naphthalenetetracarboxylic acid SOLID STATE SCIENCES 8, 2006, 1237-1242. Two new coordination polymers based on 1,4,5,8-naphthalenetetracarboxylate (ntc) has been prepared by hydrothermal methods. Their crystal structures have been determined from synchrotron powder X-ray diffraction data. Ca-2(Cl4H4O8)(H2O)(2), CPO-13, is built around infinite chains kof seven coordinated calcium atoms. Zn-2(C14H4O8)(H2O)(2), CPO-14, is isostructural with Mn-2(C14H4O8)(H2O)(2), and is built around infinite chains of corner sharing Zn octahedra. Crystal data for CPO-13: Triclinic space group P-1, with a = 5.820, b = 6.759, c = 10.168 angstrom, alpha = 72.32 degrees, beta = 86.09 degrees, gamma = 107.74 degrees, V = 357.310 angstrom(3) and Z = 1. Crystal data for CPO-14: Orthorhombic space group Pbam, with a = 9.773, b = 7.060, c = 9.879 angstrom, V = 681.729 angstrom(3) and Z = 2. The thermal properties were investigated for both compounds. An unusual anisotropic thermal expansion for CPO-14 is caused by the carboxylate groups of the me anions gradually bending away from each other. 2006-58 Floquet, S Guillou, N Negrier, P Riviere, E Boillot, ML The crystallographic phase transition for a ferric thiosemicarbazone spin crossover complex studied by X-ray powder diffraction NEW JOURNAL OF CHEMISTRY 30, 2006, 1621-1627. The crystal structure of a spin-transition compound, namely the thiosemicarbazone ferric complex Li[Fe(5BrThsa)(2)]center dot H2O, was solved from powder X-ray diffraction data at temperatures where the high-spin (373 K) and low-spin (150 K) phases prevail. The methodology is based on traditional approaches (direct methods) combined with direct space strategy. Both phases crystallise in the monoclinic system P2(1)/c. At 373 K, the characteristics of the [FeN2O2S2] coordination core are consistent with those reported for high-spin iron(III) thiosemicarbazone complexes: a distorted coordination polyhedron and non-equivalent metal-ligand bond lengths. When the temperature is reduced to 150 K, a decrease of the beta angle from ca. 101 degrees (373 K) to ca. 901 (150 K) is the only major modi. cation of the cell parameters. The low-spin molecular structure reveals significant differences in bond lengths and bond angles compared to the high-spin structure. Finally, an extended hydrogen-bond network is implicated in the cooperative phase transition, as supported by strong intermolecular contacts between the ferric complexes and the water molecules and the crystallographic phase transition is associated with pronounced lattice reorganization. 2006-59 Surble, S Millange, F Serre, C Duren, T Latroche, M Bourrelly, S Llewellyn, PL Ferey, G Synthesis of MIL-102, a chromium carboxylate metal-organic framework, with gas sorption analysis JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 14889, 14896. A new three-dimensional chromium(III) naphthalene tetracarboxylate, (Cr3O)-O-III(H2O)(2)F{C10H4-(CO2)4}(1.5).6H(2)O (MIL-102), has been synthesized under hydrothermal conditions from an aqueous mixture of Cr(NO3)(3).9H(2)O, naphthalene-1,4,5,8-tetracarboxylic acid, and HF. Its structure, solved ab initio from X-ray powder diffraction data, is built up from the connection of trimers of trivalent chromium octahedra and tetracarboxylate moieties. This creates a three-dimensional structure with an array of small one-dimensional channels filled with free water molecules, which interact through hydrogen bonds with terminal water molecules and oxygen atoms from the carboxylates. Thermogravimetric analysis and X-ray thermodiffrac-tometry indicate that MIL-102 is stable up to similar to 300 degrees C and shows zeolitic behavior. Due to topological frustration effects, MIL-102 remains paramagnetic down to 5 K. Finally, MIL-102 exhibits a hydrogen storage capacity of similar to 1.0 wt% at 77 K when loaded at 3.5 MPa (35 bar). The hydrogen uptake is discussed in relation with the structural characteristics and the molecular simulation results. The adsorption behavior of MIL-102 at 304 K resembles that of small-pore zeolites, such as silicalite. Indeed, the isotherms of CO2, CH4, and N-2 show a maximum uptake at 0.5 MPa, with no further significant adsorption up to 3 MPa. Crystal data for MIL-102: hexagonal space group P (6) over bar (No. 169), a = 12.632(1) angstrom, c = 9.622(1) angstrom. 2006-60 van Mechelen, JB Peschar, R Schenk, H Structures of mono-unsaturated triacylglycerols. I. The beta(1) polymorph ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 1121-1130. The crystal structures of the beta(1) polymorphs of monounsaturated triacylglycerols have been solved from high-resolution laboratory and synchrotron powder diffraction data for five pure compounds, the 1,3-dimyristoyl-2-oleoylglycerol (beta 1-MOM), 1,3-dipalmitoyl-2-oleoylglycerol (beta(1)-POP), 1,3-distearoyl-2-oleoylglycerol (beta(1)-SOS), 1-palmitoyl-2-oleoyl-3-stearoylglycerol (beta(1)-POS), 1-stearoyl-2-oleoyl-3-arachidoylglycerol (beta 1-SOA) and three mixtures: the co-crystallized 1:1 molar mixture of SOS and POP [beta(1)-SOS/POP (1:1)] and two cocoa butters from Bahia and Ivory Coast, both in their beta-VI (= beta 1) polymorph. All eight beta 1 structures crystallized in the space group (P2(1)/n) and have two short cell axes (5.44-5.46 and 8.18-8.22 A), as well as a very long b axis (112-135 A). The dominant-zone problem in the indexing of the powder patterns was solved with the special brute-force indexing routine LSQDETC from the POWSIM program. Structures were solved using the direct-space parallel-tempering method FOX and refined with GSAS. Along the b axis, alternations of inversion-centre- related 'three- packs' can be discerned. Each 'three-pack' has a central oleic zone, with oleic acyl chains of the molecules being packed together, that is sandwiched between two saturated-chain zones. The conformation of the triacylglycerol molecules is relatively 'flat' because the least-square planes through the saturated chains and those through the saturated parts of the olein chain are parallel. The solution of the beta 1 structures is a step forward towards understanding the mechanism of fat-bloom formation in dark chocolate and has led to a reexamination of the beta(2) structural model. 2006-61 van Mechelen, JB Peschar, R Schenk, H Structures of mono-unsaturated triacylglycerols. II. The beta(2) polymorph ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 1131-1138. An improved crystal structure model has been established for the beta(2) polymorph of the symmetric mono-unsaturated triacylglycerol 1,3-distearoyl-2-oleoylglycerol (SOS) and the equivalent beta-V polymorph of Ivory Coast cocoa butter. In addition, the crystal structures of the beta(2) polymorphs are reported for the triacylglycerols 1,3-dipalmitoyl-2-oleoylglycerol (POP) and 1-palmitoyl-2-oleoyl-3-stearoylglycerol (POS), which are, together with SOS, the major components of cocoa butter, and that of 1-stearoyl-2-oleoyl-3-arachidoylglycerol (SOA). The existence of beta 2-POS and beta 2-SOA has not been previously reported in the literature. All structures have been solved from high-resolution laboratory or synchrotron powder diffraction data with the direct-space parallel-tempering program FOX and refined with the Rietveld module of GSAS. All compounds crystallize in similar monoclinic unit cells (Cc) with very long b axes (> 127 A). The oleic chains are packed together and sandwiched between saturated chain layers, forming acyl-chain three-packs. An analysis of the beta(2) polymorphs and beta(1) polymorphs [van Mechelen et al. (2006). Acta Cryst. B62, 1121-1130] shows that they contain the same three-packs and differ only in the symmetry relation between the three-packs. The three- pack build- up provides an explanation of the mechanism of the phase transition that causes the formation of fat bloom on dark chocolate. 2006-62 Udovic, M Valant, M Jancar, B Suvorov, D Meden, A Kocevar, A Phase formation and crystal-structure determination in the Bi2O3-TiO2-TeO2 system prepared in an oxygen atmosphere JOURNAL OF THE AMERICAN CERAMIC SOCIETY 89, 2006, 3462-3469. Using X-ray diffraction analysis and scanning electron microscopy it was revealed that in an atmosphere of flowing oxygen in the temperature range 700 degrees-800 degrees C, three new compounds are formed in the Bi2O3-TiO2-TeO2 pseudoternary system. These compounds are Bi2Ti3TeO12, Bi2TiTeO8, and Bi6Ti5TeO22, and all the compounds include Te6+. All three crystal structures were solved and refined using X-ray powder diffraction data. Based on the results of the phase formation, a solid-state compatibility diagram is proposed. 2006-63 Gonen, ZS Paluchowski, D Zavalij, P Eichhorn, BW Gopalakrishnan, J Reversible cation/anion extraction from K2La2Ti3O10: Formation of new layered titanates, KLa2Ti3O9.5 and La2Ti3O9 INORGANIC CHEMISTRY 45, 2006, 8736-8742. A new soft-chemical transformation of layered perovskite oxides is described wherein K2O is sequentially extracted from the Ruddlesden-Popper (R-P) phase, K2La2Ti3O10 (I), yielding novel anion-deficient KLa2Ti3O9.5 (II) and La2Ti3O9 (III). The transformation occurs in topochemical reactions of the R-P phase I with PPh4Br and PBu4Br (Ph = phenyl; Bu = n-butyl). The mechanism involves the elimination of KBr accompanied by decomposition of PR4+ (R = phenyl or n-butyl) that extracts oxygen from the titanate. Analysis of the organic products of decomposition reveals formation of Ph3PO, Ph3P, and Ph-Ph for R = phenyl, and Bu3PO, Bu3P along with butane, butene, and octane for R = butyl. The inorganic oxides II and III crystallize in tetragonal structures (II: P4/mmm, a = 3.8335(1) angstrom, c = 14.334(1) angstrom; III: /4/ mmm, a = 3.8565(2) angstrom, c = 24.645(2) angstrom) that are related to the parent R-P phase. II is isotypic with the Dion-Jacobson phase, RbSr2Nb3O10, while III is a unique layered oxide consisting of charge-neutral La2Ti3O9 anion-deficient perovskite sheets stacked one over the other without interlayer cations. Interestingly, both II and III convert back to the parent R-P phase in a reaction with KNO3. While transformations of the R-P phases to other related layered/three-dimensional perovskite oxides in ion-exchange/metathesis/dehydration/reduction reactions are known, the simultaneous and reversible extraction of both cations and anions in the conversions K2La2Ti3O10 reversible arrow KLa2Ti3O9.5 reversible arrow La2Ti3O9 is reported here for the first time. 2006-64 Boulineau, A Joubert, JM Cerny, R Structural characterization of the Ta-rich part of the Ta-Al system JOURNAL OF SOLID STATE CHEMISTRY, 179, 2006, 3385-3393. The Ta-rich part of the Ta-Al system has been investigated. On the one hand, the accommodation of the non-stoichiometry in the a phase has been studied by Rietveld refinement of X-ray powder data obtained from different samples on both sides of the ideal composition (Ta2Al, P4(2)/mnm, tP30). On the other hand, the structure of the beta phase has been determined ab initio from powder synchrotron data (analyzed composition Ta50.7Al49.3, refined composition Ta52.6(5)Al47.4(5) (Ta45.2(4)Al40.8(4)), stoichiometric composition Ta48Al38, mP86, P2(1)/c, a = 9.8707(1) angstrom, b = 9.8766(1) angstrom, c = 16.3539(2), beta = 116.478(1), R-B = 2.6%). This phase is shown to be closely related to the group of the topologically close packed phases. In addition, phase relations have been accurately determined in the Ta-rich end of the system. 2006-65 Barrier, N Malo, S Hernandez, O HervieUa, M Hervieu, M Raveau, B The mixed valent tellurate SrTe3O8: Electronic lone pair effect of Te4+ JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3484-3488. A novel mixed valent tellurium oxide, SrTe3O8, has been synthesized and its crystal structure was determined ab initio from powder X-ray diffraction data. This oxide, which crystallizes in a tetragonal unit-cell, P4(2)/M Space group, with very close a and c cell parameters (6.8257(1) and 6.7603(1) angstrom, respectively), exhibits a very original structure built up of corner-sharing TeO6 (Te6+) octahedra and Te2O8 (Te4+) twin-pyramidal units. The latter ones form [Te3O8](infinity) chains running along the [001] and the [110] directions. Besides the four sided tunnels where the Sr2+ cations are located, there are very large four sided tunnels running along the c-axis which are obstructed by the electronic lone pairs of the Te4+ cations. 2006-66 Chong, SY Seaton, CC Kariuki, BM Tremayne, M Molecular versus crystal symmetry in tri-substituted triazine, benzene and isocyanurate derivatives ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 864-874. The crystal structures of triethyl-1,3,5-triazine- 2,4,6-tricarboxylate ( I), triethyl-1,3,5-benzenetricarboxylate ( II) and tris-2-hydroxyethyl isocyanurate ( III) have been determined from conventional laboratory X-ray powder diffraction data using the differential evolution structure solution technique. The determination of these structures presented an unexpectedly wide variation in levels of difficulty, with only the determination of ( III) being without complication. In the case of ( I) structure solution resulted in a Rietveld refinement profile that was not ideal, but was subsequently rationalized by single-crystal diffraction as resulting from disorder. Refinement of structure ( II) showed significant variation in side-chain conformation from the initial powder structure solution. Further investigation showed that the structure solution optimization had indeed been successful, and that preferred orientation had a dramatic effect on the structure-solution R-factor search surface. Despite the presence of identical side chains in ( I) and ( II), only the triazine-based system retains threefold molecular symmetry in the crystal structure. The lack of use of the heterocyclic N atom as a hydrogen-bond acceptor in this structure results in the formation of a similar non-centrosymmetric network to the benzene-based structure, but with overall three-dimensional centrosymmetry. The hydrogen-bonded layer structure of ( III) is similar to that of other isocyanurate-based structures of this type. 2006-67 Sugimoto, K Dinnebier, RE Schlecht, T Chlorartinite, a volcanic exhalation product also found in industrial magnesia screed JOURNAL OF APPLIED CRYSTALLOGRAPHY 39, 2006, 738-744. The volcanic exhalation product chlorartinite, [Mg-2(CO3)(H2O)(OH)]Cl center dot H2O, has recently been found to be a minor, and in some samples a major, component of magnesia floors for industrial use. In order to be able to perform quantitative phase analysis using the Rietveld method, its crystal structure was determined from high-resolution synchrotron powder diffraction data by the global optimization technique of simulated annealing and Rietveld refinement. The final R-p and R-wp values are 5.23% and 6.56%, respectively. Chlorartinite crystallizes in the rhombohedral space group R3c (No. 161), with a = 23.14422 (16) angstrom, c = 7.22333 (5) angstrom, V = 3350.84 (5) angstrom(3), Z = 18. The building units of chlorartinite consist of MgO6 octahedra forming 15-membered puckered rings which are interconnected by CO3 triangular moieties. The rings are stacked to form a honeycomb-like three-dimensional framework structure with large isolated channels. Within the channels, free chlorine atoms and disordered water molecules are located. 2006-68 Masciocchi, N Galli, S Sironi, A Cariati, E Galindo, MA Barea, E Romero, MA Salas, JM Navarro, JAR Santoyo-Gonzalez, F Tuning the structural and magnetic properties of thermally robust coordination polymers INORGANIC CHEMISTRY 45, 2006, 7612-7620. Thermally robust materials of the M(5-X-pyrimidin-2-olate) 2 type [M = Co, X = Cl (1(Cl)), X = Br (1(Br)), X = I (1(I)); M = Zn, X = Cl (2(Cl)), X = Br (2(Br)), X = I (2(I))] have been synthesized. Their X-ray powder diffraction structural characterization has revealed that they crystallize as vertical bar(4) over bar 2d diamondoid frameworks, isomorphous to those of the pristine [M(pyrimidin-2-olate)(2)](n) analogues (1H, M = Co; 2(H), M = Zn). The magnetic measurements of the 1(X) series at magnetic fields of 100, 300, and 5000 Oe reveal a weak ferromagnetic ordering taking place below the Neel temperature (T-N similar to 20 K), arising from spin canting phenomena of the antiferromagnetically coupled cobalt centers. Moreover, magnetic hysteresis studies carried out on the 1(X) series at 2 K reveal a strong dependence of both the coercive field H-coer (2500, 1000, 775, and 500 Oe for 1(Br), 1(Cl), 1(I), and 1(H), respectively) and the remnant magnetization M-rem (0.0501 mu(B) for 1(Br) and 1(Cl), 0.0457 mu(B) for 1(I), and 0.0358 mu(B) for 1(H)) on the 5-substituent of the pyrimidin-2-olates. The molecular alloys [Co(5-Y-pyrimidin-2-olate)(2)] (Y = Cl/Br, 1(Cl/Br)) and [Co(5-Y'-pyrimidin-2-olate)(2)] (Y' = Br/I, 1(Br /I)) have also been prepared and characterized, proving that they have intermediate properties. These materials combine interesting functional properties, such as chemical inertness, magnetism, photoluminescence, and (although weak) SHG activity. 2006-69 Voronin, VI Ponosov, YS Berger, IF Proskurnina, NV Zubkov, VG Tyutyunnik, AP Bushmelev, SN Balagurov, AM Sheptyakov, DV Burmakin, EI Shekhtman, GS Vovkotrub, EG Crystal structure of the low-temperature form of K3PO4 INORGANIC MATERIALS 42, 2006, 908-913. The crystal structure of the low-temperature form of K3PO4 has been determined for the first time using neutron diffraction (Rietveld method) and Raman spectroscopy: orthorhombic cell (sp. gr. Pnma, Z=4), lattice parameters a = 1.12377(2) nm, b = 0.81046(1) nm, c = 0.59227(1) nm. The structure is made up of isolated [PO4] tetrahedra, with the potassium ions in between. 2006-70 Colin, JF Pralong, V Caignaert, V Hervieu, M Raveau, B A novel layered titanoniobate LiTiNbO5: Topotactic synthesis and electrochemistry versus lithium INORGANIC CHEMISTRY 45, 2006, 7217-7223. A new layered titanoniobate, LiTiNbO5, an n) 2 member of the A(x)M(2n)O(4n+2) family, has been synthesized using a molten salt reaction between HTiNbO5 and an eutectic "LiOH/LiNO3". This compound crystallizes in the P2(1)/m space group with a) 6.41 angstrom, b) 3.77 angstrom, c) 8.08 angstrom, and beta = 92 degrees. It exhibits vertical bar TiNbO5 vertical bar(infinity) layers similar to HTiNbO5, but differs from the latter by a "parallel configuration" of its vertical bar TiNbO6 vertical bar(infinity) ribbons between the two successive layers. The topotactic character of the reaction suggests that exfoliation plays a prominent role in the synthesis of this new form. This new phase intercalates reversibly 0.8 lithium through a first-order transformation leading to a capacity of 94 mAh/g at a potential of 1.67 V vs Li/Li+. 2006-71 Colin, JF Bataille, T Ashbrook, SE Audebrand, N Le Polles, L Pivan, JY Le Fur, E Na-2[(VO)(2)(HPO4)(2)C2O4]center dot 2H(2)O: Crystal structure determination from combined powder diffraction and solid-state NMR INORGANIC CHEMISTRY 45, 2006, 6034-6040. The vanadyl oxalatophosphate Na-2[(VO)(2)(HPO4)(2)C2O4]center dot 2H(2)O has been synthesized by hydrothermal treatment. Its structure has been determined and refined by combining X-ray powder diffraction and solid-state NMR techniques. It crystallizes with monoclinic symmetry in space group P2(1), a = 6.3534(1) angstrom, b = 17.1614(3) angstrom, c = 6.5632(1) angstrom, beta = 106.597(1)degrees. The structure is related to that of (NH4)(2)[(VO)(2)(HPO4)(2)C2O4]center dot 5H(2)O, which was previously reported. The vanadium phosphate framework consists of infinite [(VO)(HPO4)] chains of corner-sharing vanadium octahedra and hydrogenophosphate tetrahedra. The oxalate groups ensure the connection between the chains to form a 2D structure. The sodium ions and the water molecules are located between the anionic [(VO)(2)(HPO4)(2)C2O4](2-) layers. The thermal decomposition has been studied in situ by temperature-dependent X-ray diffraction and thermogravimetry. It takes place in three stages, where the first two correspond to water removal and the last to the decomposition of the oxalate group and water elimination, leading to the final product NaVOPO4. 2006-72 Girgsdies, F Dong, WS Bartley, JK Hutchings, GJ Schlogl, R Ressler, T The crystal structure of epsilon-VOPO4 SOLID STATE SCIENCES 8, 2006, 807-812. The crystal structure of epsilon-VOPO4 was determined in the space group Cc from X-ray powder diffraction data using a rigid body approach. The resulting structure is compared to a recently published, slightly different structure model (space group P2(1)/n) using Rietveld refinement. It was found that the new Cc model consistently yields-a better fit to the observed data and exhibits a less distorted, more stable geometry. The crystal structure of epsilon-VOPO4 is discussed in comparison to beta-VOPO4, monoclinic VPO4 center dot H2O, and other related structures. 2006-73 ??? Karau, F Schnick, W A nitridic clathrate: P4N4(NH)(4)(NH3) ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45, 2006, 4505-4508. 2006-74 Bataille, T Mahe, N Le Fur, E Pivan, JY Louer, D Using the parallel tempering algorithm to overcome complex problems in structure determination of inorganic materials with laboratory X-rays ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl. 23, part 1, 2006, 9-14. The crystal structures of two inorganic compounds, Na-2[VO(HPO4)](2)(C2O4)center dot 2H(2)O and YK(C4O4)(2), have been solved ab initio from laboratory X-ray powder diffraction data using the parallel tempering algorithm. It is assumed that one reason of the failure of the direct methods in structure determination is the noticeable diffraction line overlap displayed by the powder patterns. Then, we discuss the influence of line broadening on the efficiency of the direct methods and the parallel tempering algorithm to solve back the crystal structure of,gamma-Zn2P2O7 from powder diffraction patterns simulated for several crystallite sizes. 2006-75 Aitasalo, T Holsa, J Laamanen, T Lastusaari, M Lehto, L Niittykoski, J Pelle, F Crystal structure of the monoclinic Ba2MgSi2O7 persistent luminescence material ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl. 23, part 1, 2006, 481-486. Previously unknown structure of Ba2MgSi2O7 persistent luminescence material was observed to be monoclinic with the space group C2/c (No. 15), Z = 4, a = 8.41275(1), b = 10.71005(1), c = 8.43871(1) angstrom and beta = 110.71(1)degrees based on X-ray powder diffraction data. The structure is composed of discrete [Si2O7](6-) units connected by tetrahedrally coordinated Mg atoms to form sheets in the ac plane. Layers of eight-coordinated Ba atoms run parallel to the Mg(Si2O7) sheets perpendicular to the unit cell b axis. 2006-76 Perchiazzi, N Crystal structure determination and Rietveld refinement of rosasite and mcguinnessite ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl. 23, part 1, 2006, 505-510. The crystal structure of rosasite, (Cu, Zn)(2)(CO3)(OH)(2), and mcguinnessite, (Mg,Cu)(2)(CO3)(OH)(2) have been determined from powder data. The two minerals are isostructural, with space group P2(1)/a and cell constants a=12.8976(3), b=9.3705(1), c=3.1623(1) angstrom, beta=110.262(3)degrees, V =358.54(2) angstrom(3), for rosasite and a=12.9181(4), b=9.3923(2), c=3.1622(1) angstrom, beta=111.233(3)degrees, V=357.63(2) angstrom(3) for mcguinnessite. The crystal structure refinements were lead up to R-p =7.51%, wR(p)=10.39% for rosasite and R-p =5.12%, wR(p)=6.22% for mcguinnessite. In both the two structures, the Cu coordination octahedron is distorted towards an elongated tetragonal bipyramid, whereas the Zn (in rosasite) and Mg (in mcguinnessite) coordination octahedra display an almost regular shape, their distortion being due to a partial occupancy of Cu. The carbonate group was refined as a rigid body, with a regular triangular geometry. Metal coordination octahedra polymerize through edge sharing to form octahedral "columns" and "ribbons", running along [001] and responsible for the acicular habit of these minerals. The structural relationships between rosasite and malachite are discussed. 2006-77 Kavecansky, V Mihalik, M Mat'as, S Mitroova, Z Lukacova, M Crystal structure and magnetism of Pr[Fe(CN)(6)]center dot 4D(2)O ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl. 23, part 1, 2006, 543-548. We present an analysis of neutron diffraction patterns taken from the powder Pr[Fe(CN)(6)](.)4D(2)O at room temperature and in the temperature range from 1.6 to 40 K. Deuterium atoms were localized by direct space method based on a Monte Carlo simulation process (Fox) and the structure was refined by Rietveld method. Application of detailed crystallographic analysis can be very helpful for understanding of magnetic behaviour. Although the study of magnetic properties of Pr[Fe(CN)(6)](.)4H(2)O by NMR spectroscopy, magnetization, DC and AC susceptibility measurements has indicated magnetic correlations, at low temperatures, no significant difference between low and high temperature powder neutron patterns has been detected. Neutron diffraction experiment revealed that the compound does not order magnetically down to 1.6 K. 2006-78 Baies, R Pralong, V Caignaert, V Raveau, B Soft chemistry synthesis, structure and electrochemical characterization of iron phosphates Fe(H2PO4)(3) and Fe(PO3)(3) MATERIALS RESEARCH BULLETIN 41, 2006, 1170-1177. The iron phosphate, Fe(H2PO4)(3), was synthesized through a precipitation route by means of acidic media. As the compound is highly hygroscopic, the structure was solved ab initio by powder X-ray diffraction under nitrogen flow at room temperature and 200 degrees C. This phase is antiferromagnetic below 30 K. It converts into Fe(PO3)(3) at 550 degrees C, after dehydration. Electrochemical characterizations, performed on the last compound, show irreversible decomposition into metallic iron. 2006-79 Hofmann, DWM Kuleshova, LN A method for automated determination of the crystal structures from X-ray powder diffraction data CRYSTALLOGRAPHY REPORTS 51, 2006, 419-427. An algorithm is proposed for determining the crystal structure of compounds. In the framework of this algorithm, X-ray powder diffraction patterns are compared using a new similarity index. Unlike the indices traditionally employed in X-ray powder diffraction analysis, the new similarity index can be applied even in the case of overlapping peaks and large differences in unit cell parameters. The capabilities of the proposed procedure are demonstrated by solving the crystal structures of a number of organic pigments (PY111, PR181, Me-PR170). 2006-80 Cingolani, A Galli, S Masciocchi, N Pandolfo, L Pettinari, C Sironi, A The competition between acetate and pyrazolate in the formation of polynuclear Zn(II) coordination complexes DALTON TRANSACTIONS iss 20, 2006, 2479-2486. Hydrated zinc(II) acetate reacts with pyrazole (Hpz) and, depending on the reaction conditions, forms different pyrazole-containing species, i.e. [{Zn(CH3COO)(mu-pz)(Hpz)}(2)] (1), [{Zn(CH3COO)(2)(Hpz)(2)center dot CH3COOH}] (2), [{Zn(mu-pz)(2)}(n)] (3), and [{Zn(mu-CH3COO)(mu-pz)}(n)] (4). Their structural models have been derived from single-crystal X-ray diffractometry as well as from less conventional ab-initio X-ray powder methods. All species contain tetrahedrally coordinated Zn(II) ions, with Zn-N and Zn-O bond distances close to 2.0 angstrom. The existence of the {Zn(mu-pz)}(2) core in the species 1, 3 and 4 indicates the propensity for the formation, in the presence of pyrazolate ligands, of well-defined dinuclear entities (with Zn center dot center dot center dot Zn contacts in the range 3.6-3.8 angstrom). The latter can mutually interact, in the crystals, through either hydrogen-bonding of ancillary ligands (as in 1) or coordinative bonds (via acetates, as in 4, or by self-complementarity, as in 3). The interconversion paths among these species have been studied, employing chemical and thermal methods. In particular, the topotactic and quantitative transformation of 1 into 3 by moderate heating is likely based on a solid-state cooperative condensation mechanism of the dangling pyrazolates toward neighbouring zinc(II) ions, with concomitant acetic acid extrusion. 2006-81 Braga, SS Paz, FAA Pillinger, M Seixas, JD Romao, CC Goncalves, IS Structural studies of beta-cyclodextrin and permethylated beta-cyclodextrin inclusion compounds of cyclopentadienyl metal carbonyl complexes EUROPEAN JOURNAL OF INORGANIC CHEMISTRY iss 8, 2006, 1662-1669. [CpM(CO)(n)Cl] complexes with M = Fe (n = 2) and Mo (n = 3) have been immobilised in plain beta-cyclodextrin (beta-CD) and permethylated beta-CD (TRIMEB) by methods tailored according to the stabilities and solubilities of the individual components. Four adducts were obtained with a 1: 1 host/guest stoichiometry. The compounds were studied by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), C-13{H-1} CP/MAS NMR and FTIR spectroscopy. A comparison of the experimental powder XRD data for the TRIMEB/[CpMo(CO)(3)Cl] inclusion compound with reference patterns re-vealed that the crystal packing is very similar to that reported previously for a TRIMEB/ethyl laurate inclusion compound. The unit-cell parameters refined to a = 14.731, b = 22.476, C = 27.714 angstrom (volume = 9176.3 angstrom(3)), and the space group was confirmed as P2(1)2(1)2(1). A hypothetical structural model of the inclusion compound was subsequently obtained by global optimisation using simulated annealing. 2006-82 Hansen, MR Madsen, GKH Jakobsen, HJ Skibsted, J Evaluation of Al-27 and V-51 electric field gradients and the crystal structure for aluminum orthovanadate (AlVO4) by density functional theory calculations JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 5975-5983. Three sets of crystal-structure data reported for AIVO(4) from two powder-XRD studies and a density functional theory (DFT) investigation, employing the Vienna ab initio simulation package (VASP), have been examined and refined using the DFT structure-optimization scheme implemented in the WIEN2k software. The crystal structures are evaluated on the basis of Al-27 and V-51 quadrupole coupling parameters recently reported for AIVO4, employing the corresponding electric-field gradient (EFG) tensor elements obtained from the DFT calculations. The DFT calculations provide a reliable assignment of the Al-27/V-51 resonances from three distinct Al and three V environments to the specific crystallographic sites in the asymmetric unit for AIVO4. An improved agreement between experimental quadrupole tensor elements and calculated EFG tensors is achieved after the DFT structure optimizations and consistent results are obtained using the three different structures as starting points. The improvement of the structural data is also supported by an evaluation of the Al-O and V-O bond lengths before and after DFT structure optimization. The V-51 nuclear quadrupole moment, vertical bar Q(V-51)vertical bar = 4.8 +/- 0.1 fm(2), derived from the present analysis, represents a value of higher accuracy than earlier reported Q(V-51) values. The origin of the Al-27 and V-51 EFGs are investigated by an evaluation of the orientations of the EFG tensors in the crystal frame and by an examination of the individual contributions from the valence electrons and the surrounding lattice. The latter investigation shows that the magnitude and orientation of the tensors are largely determined by the p-p(Al-27) and p-p, d-d(V-51) orbital contributions to the valence electrons, while the lattice part only gives a minor contribution for both nuclei. 2006-83 Schmidt, MU Hofmann, DWM Buchsbaum, C Metz, HJ Crystal structures of pigment Red 170 and derivatives, as determined by X-ray powder diffraction ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45, 2006, 1313-1317. 2006-84 ??? Cheung, EY Harris, KDM Kang, T Scheffer, JR Trotter, J Structure-reactivity correlations for solid-state enantioselective photochemical reactions established directly from powder X-ray diffraction JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 15554-15555. 2006-85 Sorby, MH Gunnaes, AE Lovvik, OM Brinks, HW Fjellvag, H Hauback, BC The crystal structure of Zr2NiD4.5 ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 972-978. The crystal structure of Zr2NiD4.5 has been determined by a combination of synchrotron radiation powder X-ray diffraction, electron diffraction and powder neutron diffraction data. Deuterium ordering results in a triclinic supercell given by a(super) = 6.81560 (7), b(super) = 8.85137 (9), c(super) = 8.88007 (10) A, alpha(super) = 79.8337 (8), beta(super) = 90.0987 (9), gamma(super) = 90.3634 (9)degrees, which relates to the non-super unit cell as a(super) = -a, b(super) = -b-c, c(super) = -b+c. The centrosymmetric and fully ordered deuterium sublattice was determined by simulated annealing and Rietveld refinement. Deuterium was found to occupy three types of tetrahedral sites: two that are coordinated by four Zr atoms and one that is coordinated by three Zr atoms and one Ni atom. All D-D distances are longer than 2 A. The feasibility of the crystal structure was supported by density functional theory calculations. 2006-86 Gramm, F Baerlocher, C McCusker, LB Warrender, SJ Wright, PA Han, B Hong, SB Liu, Z Ohsuna, T Terasaki, O Complex zeolite structure solved by combining powder diffraction and electron microscopy NATURE 444, 2006, 79-81. Many industrially important materials, ranging from ceramics to catalysts to pharmaceuticals, are polycrystalline and cannot be grown as single crystals. This means that non-conventional methods of structure analysis must be applied to obtain the structural information that is fundamental to the understanding of the properties of these materials. Electron microscopy might appear to be a natural approach, but only relatively simple structures have been solved by this route. Powder diffraction is another obvious option, but the overlap of reflections with similar diffraction angles causes an ambiguity in the relative intensities of those reflections. Various ways of overcoming or circumventing this problem have been developed(1,2), and several of these involve incorporating chemical information into the structure determination process(3-7). For complex zeolite structures, the FOCUS algorithm(8,9) has proved to be effective. Because it operates in both real and reciprocal space, phase information obtained from high-resolution transmission electron microscopy images can be incorporated directly into this algorithm in a simple way. Here we show that by doing so, the complexity limit can be extended much further. The power of this approach has been demonstrated with the solution of the structure of the zeolite TNU-9 (\H-9.3\[ Al9.3Si182.7O384]; ref. 10) with 24 topologically distinct ( Si, Al) atoms and 52 such O atoms. For comparison, ITQ-22 ( ref. 11), the most complex zeolite known to date, has 16 topologically distinct (Si, Ge) atoms. 2006-87 Lufaso, MW Macquart, RB Lee, Y Vogt, T zur Loye, HC Structural studies of Sr2GaSbO6, Sr2NiMoO6, and Sr2FeNbO6 using pressure and temperature JOURNAL OF PHYSICS-CONDENSED MATTER 18, 2006, 8761-8780. Results from high-pressure synchrotron x-ray diffraction and high-temperature x-ray diffraction measurements on polycrystalline samples of the tetragonal perovskites Sr2GaSbO6, Sr2NiMoO6, and Sr2FeNbO6 are reported. A phase transition, where the unit cell changes symmetry from tetragonal to cubic, is observed for each compound at elevated temperatures. The phase transition changes the structure from one exhibiting an octahedral tilting distortion at ambient temperature to one that is untilted above the transition temperature. At elevated pressures the c/v root 2a lattice parameter ratio increases, indicating that the magnitude of the octahedral tilting distortion is increasing as a function of pressure. In the pressure range studied, up to similar to 6 GPa, no phase transitions were observed. 2006-88 Fernandez-Bertran, JF Hernandez, MP Reguera, E Yee-Madeira, H Rodriguez, J Paneque, A Llopiz, JC Characterization of mechanochemically synthesized imidazolates of Ag+1, Zn+2, Cd+2, and Hg+2 : Solid state reactivity of nd(10) cations JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 67, 2006, 1612-1617. Silver, zinc, cadmium, and mercury imidazolates have been synthesized mechanochemically by milling imidazole and the metal oxides in an agate mortar. The reaction products were characterized by FTIR and XRPD techniques. The results obtained for the mechanochemical imidazolates have been compared with those obtained by precipitation reported in the literature. The mechanochemical Ag imidazolate has the same orthorhombic crystal structure as the precipitated one. The mechanochemical Zn imidazolate has a tetragonal structure with similar crystal parameters to those of Zn(Imz)(2)H2O, but no water molecules are present in the structure. This new anhydrous form is a polymorph of the one obtained by precipitation. The mechanochemical Cd imidazolate has a monoclinic structure which is the polymorph of the precipited orthorombic form. The mechanochemical Hg imidazolate presents a hexagonal structure which is a polymorph of the orthorombic structure obtained by precipitation. The influence of the nd(10) electronic configuration of the cations on the mechanochemical reaction is discussed. 2006-89 Pandian, RP Kim, YI Woodward, PM Zweier, JL Manoharan, PT Kuppusamy, P The open molecular framework of paramagnetic lithium octabutoxynaphthalocyanine: implications for the detection of oxygen and nitric oxide using EPR spectroscopy JOURNAL OF MATERIALS CHEMISTRY 16, 2006, 3609-3618. The oxygen-induced broadening of the electron paramagnetic resonance (EPR) spectrum of lithium octa-n-butoxy-naphthalocyanine (LiNc-BuO) is interpreted in terms of its open molecular framework crystal structure. LiNc-BuO was prepared as a microcrystalline powder and its structure analyzed using X-ray powder diffraction techniques. The structure contains strongly coupled dimers of LiNc-BuO molecules, which favors a high degree of spin exchange, and results in a single sharp EPR line. The molecular packing leads to a structure with open channels large enough (10 x 6 angstrom(2)) for the penetration of small diatomic paramagnetic molecules such as oxygen (O-2) and nitric oxide (NO), as well as the larger triatomic species, nitrogen dioxide (NO2). The EPR linewidth of LiNc-BuO is extremely sensitive to the concentration of paramagnetic gases in the pressure range of 0 - 760 mmHg. The effect of oxygen on LiNc-BuO is reversible without any signs of permanent adsorption or chemical oxidation. The time response of the effect of oxygen is extremely rapid (0.24 s). The paramagnetic gas-sensing properties of LiNc-BuO are attributed to the open molecular framework of the crystal structure. The oxygen-sensing property, combined with the previously established biostability and biocompatibility of this material, should enable precise and accurate measurements of oxygen concentration in biological systems using EPR spectroscopy. 2006-90 Asthalter, T Sergueev, I van Burck, U Dinnebier, R Identification of a rotator phase of octamethyl ferrocene and correlations between its structural and dynamical properties JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 67, 2006, 1416-1422. The low- and high-temperature phases of octamethyl ferrocene were studied in detail, using high-resolution X-ray powder diffraction, differential scanning calorimetry and nuclear resonant scattering, in particular the novel technique of synchrotron radiation perturbed angular correlations (SRPAC). Much as in the case of an analogous but more unsymmetrical molecule, octamethyl ethinyl ferrocene, the high-temperature phase possesses the space group R3m with lattice parameters a = b = 12.5568(1) angstrom, c = 9.6045(1) angstrom, which in the rhombohedral setting correspond to a = 7.9251(1) angstrom, alpha = 104.79 degrees. An increase of the volume per formula unit of about 12% across the phase transition is observed. The rotation of the electric field gradient, which can be identified with the rotation of the entire molecule within the lattice, follows Arrhenius behaviour with a high activation energy of (40.3 +/- 3.3) kJ mol(-1). Whereas precursor effects and a change in activation energy were observed for octamethyl ethinyl ferrocene, no such effects are observed for octamethyl ferrocene. We relate this difference to the absence of the ethinyl substituent in octamethyl ferrocene. 2006-91 ??? Li, RK Yu, Y Ba4Ga2B8O18Cl2, NaCl: A new polar structure with NaCl inclusion INORGANIC CHEMISTRY 45, 2006, 6840-6843. The title compound, Ba4Ga2B8O18Cl2, NaCl, is found to crystallize in a polar space group P4(2)nm with cell dimensions of a = 12.1134(2) angstrom and c = 6.8456(1) angstrom. The basic building blocks of the structure are the B4O9 groups, which are interconnected by the GaO4 tetrahedron to form a three-dimensional net with Ba-2(+) ion-, Cl- ion-, and NaCl molecule-filled tunnels. This net structure is closely related to that of mineral hilgardite, with which many variant compounds have been found. Both a powder second-harmonic-generation test and calculations suggest that it possesses an optical nonlinearity comparable to that of potassium dihydrogen phosphate. 2006-92 Dorset, DL Kennedy, GJ Strohmaier, KG Diaz-Cabanas, MJ Rey, F Corma, A P-derived organic cations as structure-directing agents: Synthesis of a high-silica zeolite (ITQ-27) with a two-dimensional 12-ring channel system JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 8862-8867. Recently, efforts have been made to synthesize large-pore, multidimensional zeolite frameworks as a basis for new catalysts to improve various hydrocarbon conversions. A new aluminosilicate zeolite, ITQ-27, has been prepared using the phosphorus-containing structure-directing agent, dimethyldiphenylphosphonium. Its crystal structure was determined in its calcined form by direct methods ( FOCUS) on synchrotron powder diffraction data (lambda = 0.8702 angstrom) after the unit cell and space group were determined from tilt electron diffraction experiments on individual microcrystals. The material crystallizes in space group Fmmm, where a = 27.7508(5) angstrom, b = 25.2969(7) angstrom, and c = 13.7923(4) angstrom. The final model, refined by Rietveld methods, comprises seven unique T-sites forming a framework with straight 12-MR channels that are connected by 14-MR openings between them. ( Corresponding 12-ring pore dimension is 6.94 angstrom x 6.20 angstrom.) Since access from one 14-MR opening to the next is through the 12-MR channel, the structure is best described as a two-dimensional, 12-MR framework. 2006-93 Ben Yahia, H Gaudin, E Darriet, J Dai, D Whangbo, MH Comparison of the crystal structures and magnetic properties of the low- and high-temperature forms of AgCuPO4: Crystal structure determination, magnetic susceptibility measurements, and spin dimer analysis INORGANIC CHEMISTRY 45, 2006, 5501-5509. The crystal structure of the low-temperature form of AgCuPO4 (i.e., alpha-AgCuPO4) was determined by powder X-ray diffraction and was compared with that of the high-temperature form of AgCuPO4 (i.e. beta-AgCuPO4). The magnetic properties of the two forms were examined by measuring their magnetic susceptibilities and evaluating the relative strengths of their spin-exchange interactions on the basis of spin-dimer analysis. Both forms of AgCuPO4 have layers of Cu2P2O8 alternating with silver-atom double layers; beta-AgCuPO4 has two Cu2P2O8 layers per unit cell, while alpha-AgCuPO4 has one. The coordinate environment of each Cu2+ ion is close to being a distorted square pyramid in alpha-AgCuPO4, but it is close to being a distorted trigonal bipyramid in beta-AgCuPO4. The magnetic susceptibilities of alpha- and beta-AgCuPO4 are well simulated by an antiferromagnetic alternating-chain model, which leads to J/K-B = -146.1 K and alpha J/K-B = -75.8 K for alpha-AgCuPO4, and J/K-B = -82.6 K and alpha J/K-B = -31.7 K for beta-AgCuPO4 (with the convention in which the spin-exchange parameter between two adjacent spin sites is written as 2J). The spin gaps, Delta/K-B, obtained from these parameters are 93.7 K for alpha-AgCuPO4 and 62.3 K for beta-AgCuPO4. The strongest spin exchange in both forms of AgCuPO4 comes from a super-superexchange path, and this interaction is stronger for R-AgCuPO4 than for beta-AgCuPO4 by a factor of similar to 2, in good agreement with the experiment. Our analysis supports the use of this model for beta-AgCuPO4 and indicates that the spin lattice of alpha-AgCuPO4 would be better described by a two-dimensional net made up of weakly interacting alternating chains. 2006-94 Kirik, SD Starkov, AK Kozhuhovskay, GA cis-Amminedichloroisopropylamine-platinum(II) by X-ray powder diffraction analysis ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 62, 2006, M249-M251. The title compound, [PtCl2(C3H9N)(NH3)], was obtained from potassium tetrachloroplatinate(II) by a two-step route. Ab initio crystal structure determination was carried out using X-ray powder diffraction techniques. Patterson and Fourier syntheses were used for the atom locations and the Rietveld technique for the final structure refinement. The Pt coordination is close to planar, with Cl atoms in a cis orientation. Molecules are combined into groups of two molecules, with antiparallel PtN2Cl2 planes and a shortest Pt center dot center dot center dot Pt distance of 3.42 angstrom. The molecule groups are packed in a parquet motif into corrugated layers parallel to ab. The molecules in the layers are linked by H-N center dot center dot center dot Cl hydrogen bonds. 2006-95 Derollez, P Hedoux, A Guinet, Y Lefebvre, J Descamps, M Hernandez, O Micro(nano)structure of the glacial state in triphenyl phosphite (TPP) ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl. 23, part 2, 2006, 557-562. The structure and microstructure of the glacial state in triphenyl phosphite (TPP, P(OC6H5)(3)) transformed at 222 K have been determined from powder synchrotron X-ray diffraction data through Rietveld and Le Bail refinements. It is shown that the glacial state is composed of crystallites of the stable crystal phase coexisting with non-transformed supercooled liquid. The apparent size of the crystallites - depending on the ageing temperature at which the glacial state is isothermally formed - is found to be equal to 329.2(2) angstrom at 222 K. A simulated diffraction pattern shows that at temperatures lower than 220 K, the more amorphous-like shape is due to the coexistence of non-transformed supercooled liquid and to a size effect of the crystallites of the stable phase. 2006-96 Ramirez-Cardona, M Escamilla-Casas, JC Cuevas-Diarte, MA Barajas-Rosales, I Structure determination of 1-pentanol (C5H12O)at 183 K ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl 23 part 2, 2006, 601-606. Powder X-ray diffraction pattern of the crystalline phase of I-pentanol was recorded with a sensitive curved detector (CPS120) at 183 K. The structure has been solved with the Patterson Search [1] method. The resulting structure was refined by rigid-body Rietveld analysis. The cell is monoclinic, space group P2(1)/c, Z = 4 and with the following parameters: a = 15.592(g) angstrom, b = 4.349(1) angstrom, c = 9.157(1) angstrom, beta = 104.7(7)degrees, V = 600.6(3) angstrom(3). The structure contains one molecule in the asymmetric unit with the O-H bond in gauche conformation with respect to the alkyl skeleton. Packing is defined by OH... OH hydrogen bonds that link the I-pentanol molecules along the b axis as zigzag chains. 2006-97 Pan, ZG Xu, MC Cheung, EY Harris, KDM Constable, EC Housecroft, CE Understanding the structural properties of a dendrimeric material directly from powder X-ray diffraction data JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 11620-11623. Complete structure determination of an early-generation dendrimeric material has been carried out directly from powder X-ray diffraction data, using the direct-space genetic algorithm technique for structure solution followed by Rietveld refinement. This work represents the first application of modern direct-space techniques for structure determination from powder X-ray diffraction data in the case of a dendrimeric material and paves the way for the future application of this approach to enable complete structure determination of other dendrimeric materials that cannot be prepared as single crystal samples suitable for single crystal X-ray diffraction studies. 2006-98 Dinnebier, R Sofina, N Hildebrandt, L Jansen, M Crystal structures of the trifluoromethyl sulfonates M(SO3CF3)(2) (M = Mg, Ca, Ba, Zn, Cu) from synchrotron X-ray powder diffraction data ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 467-473. The crystal structures of divalent metal salts of trifluoromethyl sulfonic acid ('trifluoromethyl sulfonates') M( SO3CF3)(2) (M = Mg, Ca, Ba, Zn, Cu) were determined from high-resolution X-ray powder diffraction data. Magnesium, calcium and zinc trifluoromethyl sulfonate crystallize in the rhombohedral space group R (3) over bar . Barium trifluoromethyl sulfonate crystallizes in the monoclinic space group I2= a(C2/c) and copper trifluoromethyl sulfonate crystallizes in the triclinic group P (1) over bar. Within the crystal structures the trifluoromethyl sulfonate anions are arranged in double layers with the apolar CF3 groups pointing towards each other. The cations are located next to the SO3 groups. The symmetry relations between the different crystal structures have been analysed. 2006-99 Hildebrandt, L Dinnebier, R Jansen, M Crystal structure and ionic conductivity of three polymorphic phases of rubidium trifluoromethyl sulfonate, RbSO3CF3 INORGANIC CHEMISTRY 45, 2006, 3217-3223. The crystal structures of three polymorphic phases of rubidium trifluoromethyl sulfonate (RbSO3CF3, rubidium 'triflate') were solved from X-ray powder diffraction data. At room temperature, rubidium triflate crystallizes in the monoclinic space group Cm with lattice parameters of a = 19.9611(5) angstrom, b = 23.49113(7) angstrom, c = 5.1514(2) angstrom, beta = 102.758(2)degrees; Z = 16. At T = 321 K, a first-order phase transition occurs toward a monoclinic phase in space group P2(1) with lattice parameters at T = 344 K of a = 10,3434(5) angstrom, b = 5.8283(3) angstrom, c = 5.1982(3) angstrom, beta = 104.278(6)degrees; Z = 2). At T = 461 K, another phase transition, this time of second order, occurs toward an orthorhombic phase in space group Cmcm with lattice parameters at T = 510 K of a = 5.3069(2) angstrom, b = 20.2423(10) angstrom, c = 5.9479(2) angstrom; Z = 4. As a common feature within all three crystal structures of rubidium triflate, the triflate anions are arranged in double layers with the lipophilic CF3 groups facing each other. The rubidium ions are located between the SO3 groups. The general packing is similar to the packing in cesium triflate. Rubidium triflate can be classified as a solid electrolyte with a specific ionic conductivity of sigma = 9.89 x 10(-9) S/cm at T = 384 K and sigma = 3.84 x 10(-6) S/cm at T = 481 K. 2006-100 Leineweber, A Nitsche, H La5Al3Ni2 - an intermetallic phase observed upon crystallization of La50Al25Ni25 metallic glass ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 632, 2006, 553-558. The yet unknown intermetallic phase La5Al3Ni2 was obtained by partially crystallizing amorphous La50Al25N25 at 550 K (further heating above 600 K leads to irreversible disappearance of this phase), and its crystal structure was determined from X-ray powder diffraction data. The crystal structure of the La5Al3Ni2 phase constitutes a new structure type (C-mcm, a = 14.231 angstrom, b = 6.914 angstrom, c = 10.460 angstrom, oC40) and is built from [Al3Ni2] chains surrounded by La atoms. In the ternary system La-Al-Ni La5Al3Ni, is located on the section La50Al50-nNin (0 <= n <= 50) with the binary compounds LaAl and LaNi as end members. Strikingly, also the crystal structures of the end members can be conceived as chain structures with Al and Ni chains surrounded by La, respectively. 2006-101 Funke, K Banhatti, RD Wilmer, D Dinnebier, R Fitch, A Jansen, M Low-temperature phases of rubidium silver iodide: Crystal structures and dynamics of the mobile silver ions JOURNAL OF PHYSICAL CHEMISTRY A 110, 2006, 3010-3016. Recently, broad-band conductivity spectra have been taken in the low-temperature gamma-phase of the archetypal fast ion conductor RbAg4I5. Attempts to reproduce the experimental data in a simple model calculation have led to the conclusion that strictly localized displacive movements of interacting ionic charge carriers should play an important role in the low-temperature phase. However, with no detailed structural study of gamma-RbAg4I5 available, the relevant processes could not be identified within the crystal structure. This state of affairs has triggered the present investigation of the structures of all three phases of rubidium silver iodide. Powder diffraction data of RbAg4I5 have been collected at the high-resolution powder diffractometer at ID31 at the European Synchrotron Radiation Facility (ESRF). The structure of the gamma-phase has been solved by successive Rietveld refinements in combination with difference Fourier analyses. The same structural principle is found to prevail in all three phases, interconnected distorted RbI6 octahedra forming a three-dimensional framework, which undergoes only displacive structural changes during the alpha - beta and beta - gamma phase transitions. With decreasing temperature, the disorder in the silver sublattice is found to decrease, and a clustering of the disordered silver ions is found to develop. In the gamma-phase, "pockets" containing partially occupied silver sites have been identified, and it is suggested that the localized displacive motion detected by conductivity spectroscopy is performed by the silver ions located within these pockets. 2006-102 Yang, XB Synthesis and crystal structure of tetramethylammonium fluoride octadecasil MATERIALS RESEARCH BULLETIN 41, 2006, 54-66. Octadecasil, a clathrate-type inclusion compound, has been synthesized hydrothermally at 453 K with a gel having the composition 1.0SiO(2):0.53tetramethylammonium (TMA(+)):0.54fluoride:86H(2)O. The crystal structure has been determined based on powder X-ray diffraction data taken at 298 K, and has been refined using Rietveld method. The result confirms the AST-type, all-silica framework model developed by Caullet et al. [P. Caullet, J.L. Guth, J. Hazm, J.M. Lamblin, H. Gies, Eur. J. Solid State Inorg. Chem. 28 (1991) 345]. Furthermore, by using a rigid body model the position and orientation of the occluded TMA(+) cation in the rhombododecahedral [4(6)6(12)] cage can be determined; F- anion has been located in the hexahedral [4(6)] cage. The unit cell parameters, in the tetragonal space group I4/m, have been refined as: a = b = 9.07 angstrom, c = 13.44 angstrom, cell volume = 1104.97 angstrom(3). The refined unit cell composition is \[N(CH3)(4)(+)](2.0)F-1.9(-)\[Si20O40], i.e., both TMA(+) and F- ions possess near full occupancies, and compensate each other's electronic charges. The crystallization of the AST framework structure is the result of a cooperative structure-directing effect of both ions. 2006-103 Guguta, C Meekes, H de Gelder, R Crystal structure of aspartame anhydrate from powder diffraction data. Structural aspects of the dehydration process of aspartame CRYSTAL GROWTH & DESIGN 6, 2006, 2686-2692. Aspartame has three pseudo-polymorphic forms, two hydrates and a hemi-hydrate, for which crystal structures were determined from single-crystal diffraction data. This paper presents the crystal structure of the anhydrate, which was obtained by dehydrating the hemi-hydrate. The crystal structure of aspartame anhydrate, L-aspartyl-L-phenylalanine methyl ester, was determined from X-ray powder diffraction data. Aspartame anhydrate crystallizes in the monoclinic system with space group P2(1) and cell parameters: a = 19.4078( 10) angstrom, b = 4.9605(2) angstrom, c = 15.6547(9) angstrom, beta = 94.876( 2), V = 1501.65(14) angstrom(3). Final Rietveld refinement resulted in R-wp = 2.26 and a GOOF of 2.30. Comparing the hydrates of aspartame and using molecular modeling provide a complete and clear picture of the dehydration behavior of aspartame at the molecular level. 2006-104 Fukuda, K Wata, T Niwa, T Crystal structure and phase transformations of calcium yttrium orthophosphate, Ca3Y(PO4)(3) JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3420-3428. Crystal structure and phase transformations of calcium yttrium orthophosphate Ca3Y(PO4)(3) were investigated by X-ray powder diffraction, selected-area electron diffraction, transmission electron microscopy and optical microscopy. The high-temperature phase is isostructural with eulytite, cubic (space group I (4) over bar 3d) with a = 0.983320(5) nm, V = 0.950790(8) nm(3), Z = 4 and D-x = 3.45 Mg m(-3). The crystal structure was refined with a split-atom model, in which the oxygen atoms are distributed over two partially occupied sites. Below the stable temperature range of eulytite, the crystal underwent a martensitic transformation, which is accompanied by the formation of platelike surface reliefs. The inverted crystal is triclinic (space group P1) with a = 1.5726(1) nm, b = 0.84267(9) nm, c = 0.81244(8) nm, alpha = 109.739(4)degrees, beta = 90.119(5)degrees, gamma = 89.908(7)degrees, V = 1.0134(1) nm(3), Z = 4 and D-x = 3.24 Mg m(-3). The crystal grains were composed of pseudo-merohedral twins. The adjacent twin domains were related by the pseudo-symmetry mirror planes parallel to {10 (1) over bar} with the composition surface {10 (1) over bar}. When the eulytite was cooled relatively slowly from the stable temperature range, the decomposition reaction of Ca(3)y(PO4)(3)->beta-Ca-3(PO4)(2)+YPO4 occurred. 2006-105 Stephenson, GA Liang, C Structural determination of the stable and meta-stable forms of atomoxetine HCl using single crystal and powder X-ray diffraction methods JOURNAL OF PHARMACEUTICAL SCIENCES 95, 2006, 1677-1683. Strattera (TM) is the first FDA-approved nonstimulant medication for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in children, adolescents, and adults. Two polymorphic forms and an amorphous form of the active pharmaceutical ingredient, atomoxetine HCl, were discovered during drug development. The thermodynamically stable polymorphic form was selected for the commercial product. The stable form readily grows as crystals suitable for single crystal diffraction. The meta-stable crystal form is isolated by rapid crystallization, providing crystals that are too small for routine single crystal methods; consequently its structure was determined by X-ray powder diffraction. 2006-106 Stinton, GW Hampson, MR Evans, JSO The 136-atom structure of ZrP2O7 and HfP2O7 from powder diffraction data INORGANIC CHEMISTRY 45, 2006, 4352-4358. There has been considerable debate in the literature about the true room-temperature structure of ZrP2O7 and related materials. In this article we describe how a combination of information from solid-state P-31 NMR and powder diffraction data can be used to determine the structure of this 136 unique-atom material. The structure has been solved using a combination of simulated annealing and Rietveld refinement performed simultaneously on X-ray and neutron diffraction data. Despite the close to cubic metric symmetry of the material, we show how its true orthorhombic structure ( space group Pbca) can be refined to a high degree of precision. 2006-107 Rajeswaran, M Blanton, TN Giesen, DJ Whitcomb, DR Zumbulyadis, N Antalek, BJ Neumann, MM Misture, ST Azine bridged silver coordination polymers: Powder X-ray diffraction route to crystal structure determination of silver benzotriazole JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 1053-1059 In continuation of our interest in solid-state Structures of silver complexes of photographic importance, the structure for silver benzotriazole (AgBZT), has now been obtained. The preferred method for solving crystal structures is via single-crystal X-ray diffraction (XRD). However, for some materials, growing single crystals of appropriate size and quality is often difficult or even impossible. AgBZT is an example of such a silver complex with poor solubility. The usual routes to preparing single crystals using recrystallization from a cooperating solvent resulted in polycrystalline powder samples. We propose a crystal Structure for AgBZT, solved from synchrotron X-ray powder diffraction data, using a direct-space Monte Carlo simulated annealing approach. AgBZT crystals are monoclinic, (P2(1)/c), with unit cell dimensions, a = 14.8052(3) angstrom, b = 3.7498(4) angstrom, c = 12.3495(12) angstrom. and beta = 114.200(6)degrees. The AgBZT complex is constructed from all three of the Benzotriazole (BZT) nitrogens bonding to a separate silver atom. As a consequence of this bonding mode, the Structure is a highly cross-linked, coordination polymer. 2006-108 Wallez, G Souron, JP Quarton, M Crystal structure and thermal evolution of inedite alpha-Zr2O(PO4)(2) and alpha-Hf2O(PO4)(2) SOLID STATE SCIENCES 8, 2006, 1061-1066. The structures of isotypic alpha-Zr2O(PO4)(2) (S.G. I2/m, a = 10.2726(6), b = 6.5957(3), c 10.0665(5) angstrom, beta = 95.433(3)degrees, V = 679.00(6) angstrom(3), Z = 4) and alpha-Hf2O(PO4)(2) (S.G. I2/m, a = 10.2301(3), b 6.5819(2), c = 10.0075(5) angstrom, 95.371(1)degrees,. V = 670.87(3) angstrom(3), Z = 4) have been resolved ab initio by Rietveld analysis. At variance with the beta-form, they show both MO6 and MO7 polyhedra (M = Zr, Hf), forming ribbons with the PO4 tetrahedra. A lattice energy calculation explains why the alpha-form is less stable than the beta-form, thus making the alpha-beta transition irreversible. However, the substitution of smaller Hf-IV for Zr-IV allows to keep the a-framework up to 1500 degrees C by stabilizing the MO6 octahedra. 2006-109 Karray, R Kabadou, A Ben Salah, A van der Lee, A X-ray powder diffraction study of cesium ammonium hexachlorotellurate [Cs-0.86(NH4)(0.14)](2)TeCl6 POWDER DIFFRACTION 21, 2006, 225-228. The crystal structure of cesium ammonium hexachlorotellurate [Cs-0.86(NH4)(0.14)](2)TeCl6, has been determined using X-ray powder diffraction techniques. At room temperature, the title compound crystallizes in the cubic space group Fm (3) over barm, with a lattice parameter a = 10.470(17) angstrom. The Rietveld refinement of the structure led to final confidence factors R-p=0.0338 and R-wp=0.0487. The structure of [Cs-0.86(NH4)(0.14)](2)TeCl6 belongs to the large family of K2PtCl6-related structures. The H atoms of the ammonium group are orientated with its apex toward Te atoms as seen in the related compound (NH4)(2)SiF6. An IR spectroscopic study was performed to confirm the results of the diffraction method, notably concerning the presence of the ammonium group. 2006-110 de Armas, HN Peeters, OM Blaton, N van den Mooter, G de Ridder, DJA Schenk, H Crystal structure of carnidazole form II from synchrotron X-ray powder diffraction: Structural comparison with form I, the hydrated form and the low energy conformations in vacuo JOURNAL OF PHARMACEUTICAL SCIENCES 95, 2006, 2123-2136. The crystal structure of carnidazole form II, O-methyl [2-(2-methyl-5-nitro1H-imidazole-1-yl)ethyl]thiocarbamate, has been determined using synchrotron X-ray powder diffraction in combination with simulated annealing and whole profile pattern matching, and refined by the Rietveld method. For structure solution, 12 degrees of freedom were defined: one motion group and six torsions. Form II crystallizes in space group P2(1)/n, Z = 4, with unit cell parameters after Rietveld refinement: a = 13.915(4), b=8.095(2), c=10.649(3) angstrom, beta=110.83(1)degrees, and V=1121.1(5)angstrom(3). The two polymorphic forms, as well as the hydrate, crystallize in the monoclinic space group P21/n having four molecules in the cell. In form II, the molecules are held together by forming two infinite zig-zag chains via hydrogen bonds of the type N-H...N, the same pattern as in form I. A conformational study of carnidazole, at semiempirical PM3 level, was performed using stochastic approaches based on modification of the flexible torsion angles. The values of the torsion angles for the molecules of the two polymorphic forms and the hydrate of carnidazole are compared to those obtained from the conformational search. Form I and form II are enantiotropic polymorphic pairs this agrees with the fact that the two forms are conformational polymorphs. 2006-111 ??? Hirano, S Toyota, S Toda, F Fujii, K Uekuasa, H Solid-state phase transition of an inclusion complex of 5-methyl-2-pyridone with 1,3,5-benzenetricarboxylic acid ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 45, 2006, 6013-6016. 2006-112 Mahe, N Audebrand, N Structure and thermal behaviour of ScK(C2O4)(2)(H2O)(2) and InRb1-x(H3O)(x)(C2O4)(2)(H2O)(2)center dot 0.5(H2O): Two members of a family of open-framework oxalates with isotypic helical structures and zeolite-like properties SOLID STATE SCIENCES 8, 2006, 988-999. Two new mixed oxalates with an open architecture, ScK(C2O4)(2)(H2O)(2) (I) and InRb0.77(H3O)(0.23)(C2O4)(2)(H2O)(2).0.5(H2O) (II), have been synthesised from precipitation methods at ambient temperature. They crystallize in hexagonal system, space group P6(2)22 (No. 180), Z = 3, with the following unit-cell parameters for I: a = 8.8667(2) angstrom, c = 11.4908(4) angstrom, V = 782.36(4) angstrom(3), for II: a = 9.0148(3) angstrom, c = 11.4645(3) angstrom, V = 806.86(4) angstrom(3). The two structures belong to a family of isotypic helical anionic open-frameworks built from square antiprismatic coordinated metals and bischelating oxalates. The counter-cations K+ and Rb+/H3O+ are located in the tunnels of the framework. The thermal decomposition process has demonstrated zeolite-like properties associated with weakly-bonded water molecules located in the voids of the framework. 2006-113 Sassoye, C de Kozak, A Crystal structure and thermal behaviour of K-2[CrF5 center dot H2O] ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 632, 2006, 445-448. K-2[CrF(5)center dot H2O] is monoclinic: a = 9.6835(3) angstrom, b = 7.7359(2) angstrom, c = 7.9564(3) angstrom, beta = 95.94(1)degrees, Z = 4, space group C2/c (n degrees 15). Its crystal structure was solved from its X-ray powder pattern recorded on a powder diffractometer, using for the refinement the Rietveld method. It is built up from isolated octahedral [CrF(5)center dot OH2](2-) anions separated by potassium cations. The dehydration of K-2[CrF(5)center dot H2O] leads to anhydrous orthorhombic K2CrF5: a = 7.334(2) angstrom, b = 12.804(4) angstrom, c = 20.151(5) angstrom, Z = 16, space group Pbcn (n degrees 60), isostructural with K2FeF5. 2006-114 Marichal, C Chezeau, JM Roux, M Patarin, J Jorda, JL McCusker, LB Baerlocher, C Pattison, P Synthesis and structure of Mu-33, a new layered aluminophosphate vertical bar((CH3)(3)CNH3+)(16)(H2O)(4)vertical bar[Al16P24O88(OH)(8)] MICROPOROUS AND MESOPOROUS MATERIALS 90, 2006, 5-15. Mu-33, a new layered aluminophosphate with an Al/P ratio of 0.66, was obtained from a quasi non-aqueous synthesis in which tert-butylformamide (tBF) was the main solvent and only limited amounts of water were present. During the synthesis, tBF decomposed and the resulting protonated tert-butylamine is occluded in the as-synthesized material. The approximate structure was determined from data collected on a microcrystal (200 x 25 x 5 mu m(3)) at the European Synchrotron Radiation Facility (ESRF) in Grenoble, but the quality of these data did not allow satisfactory refinement. Therefore the structure was refined using high-resolution powder diffraction data, also collected at the ESRF. The structure (P2(1)/c, a = 9.8922(6) angstrom, b = 26.180(2) angstrom, c = 16.729(1) angstrom and beta = 90.4(1)degrees) consists of anionic aluminophosphate layers that can be described as a six-ring honeycomb of alternating corner-sharing AlO4 and PO4 tetrahedra with additional P-atoms above and below the honeycomb layer bridging between Al-atoms. The tert-butylammonium ions and water molecules located in the interlayer spacing interact via hydrogen-bonds with the terminal oxygens of the P-atoms. The characterization of this new aluminophosphate by C-13, P-31, H-1-P-31 heteronuclear correlation (HETCOR) and Al-27 3QMAS solid state NMR spectroscopy is also reported. 2006-115 Dova, E Peschar, R Sakata, M Kato, K Schenk, H High-spin- and low-spin-state structures of [Fe(chloroethyltetrazole)(6)](ClO4)(2) from synchrotron powder diffraction data CHEMISTRY-A EUROPEAN JOURNAL 12, 2006, 5043-5052. The spin-crossover complex [Fe(teeC)(6)](ClO4)(2) (teec = chloroethyltetrazole) exhibits a 50% incomplete spin crossover in the temperature range 300-30 K. Time-resolved synchrotron powder diffraction experiments have been carried out to elucidate its structural behavior. We report crystal structure models of this material at 300 K (high spin) and 90 K (low spin), as solved from synchrotron powder diffraction data by using Genetic Algorithm and Parallel Tempering techniques and refined with Rietveld refinement. During short synchrotron powder diffraction experiments (five minutes duration) two distinguishable lattices were observed the quantities of which vary with temperature. The implication of this phenomenon, that is interpreted as a structural phase transition associated with the high-tolow spin crossover, and the structural characteristics of the high-spin and low-spin models are discussed in relation to other compounds showing a similar type of spin-crossover behavior. 2006-116 Hinrichsen, B Dinnebier, RE Rajiv, P Hanfland, M Grzechnik, A Jansen, M Advances in data reduction of high-pressure x-ray powder diffraction data from two-dimensional detectors: a case study of Schafarzikite (FeSb2O4) JOURNAL OF PHYSICS-CONDENSED MATTER 18, 2006, S1021-S1037. Methods have been developed to facilitate the data analysis of multiple two-dimensional powder diffraction images. These include, among others, automatic detection and calibration of Debye-Scherrer ellipses using pattern recognition techniques, and signal filtering employing established statistical procedures like fractile statistics. All algorithms are implemented in the freely available program package Powder3D developed for the evaluation and graphical presentation of large powder diffraction data sets. As a case study, we report the pressure dependence of the crystal structure of iron antimony oxide FeSb2O4 ( p <= 21 GPa, T = 298 K) using high-resolution angle dispersive x-ray powder diffraction. FeSb2O4 shows two phase transitions in the measured pressure range. The crystal structures of all modifications consist of frameworks of Fe2+O6 octahedra and irregular Sb3+O4 polyhedra. At ambient conditions, FeSb2O4 crystallizes in space group P4(2)/mbc ( phase I). Between p = 3.2 GPa and 4.1 GPa it exhibits a displacive second order phase transition to a structure of space group P2(1)/c ( phase II, a = 5.7792( 4) angstrom, b = 8.3134( 9) angstrom, c = 8.4545( 11) angstrom, beta = 91.879( 10)degrees, at p = 4.2 GPa). A second phase transition occurs between p = 6.4 GPa and 7.4 GPa to a structure of space group P4(2)/m ( phase III, a = 7.8498( 4) angstrom, c = 5.7452( 5) angstrom, at p = 10.5 GPa). A nonlinear compression behaviour over the entire pressure range is observed, which can be described by three Vinet equations in the ranges from p = 0.52 GPa to p = 3.12 GPa, p = 4.2 GPa to p = 6.3 GPa and from p = 7.5 GPa to p = 19.8 GPa. The extrapolated bulk moduli of the high-pressure phases were determined to K-0 = 49( 2) GPa for phase I, K-0 = 27( 3) GPa for phase II and K-0 = 45( 2) GPa for phase III. The crystal structures of all phases are refined against x-ray powder data measured at several pressures between p = 0.52 GPa, and 10.5 GPa. 2006-117 Torres-Martinez, LM Ibarra, J Loredo, JR Garza-Tovar, LL Martinez-Bruno, O Phase formation and crystal structure of ternary compound Na2Li2Ti6O14 SOLID STATE SCIENCES 8, 2006, 1281-1289. A systematic study into phase formation in the system Na2O-Li2O-TiO2 has been carried out at subsolidus temperatures, ca. 900-1000 degrees C. An. experimental study of compound formation and phase equilibrium in this ternary system for compositions containing > 50% TiO2 was made. Five ternary phases were encountered; three of them have variable composition. Solid solution called phase A, is centered on Na5.4Li1.6Ti6.5O16.5 (isostructural to Na0.68Ni0.34Ti0.66O2), phase B is centered on Na2Li2Ti6O14 (isostructural to SrLi2Ti6O14), and phase C is based on Na2LiTi8.5O18.5 (isostructural to Na2Fe2Ti6O16). Two ternary compounds were also found with composition: Na5.6Li2.8Ti5.8O15.8 and Na7Li3Ti5O15 (isostructural to Na0.75Fe0.75Ti0.25O2 and Na2.76Li1.24Ti2O6 respectively). The sodium lithium titanate with composition Na2Li2Ti6O14 has been synthesized by solid state reaction at 970 degrees C. The characterization was made by X-ray powder diffraction technique. The structure of Na2Li2Ti6O14 was solved using X-ray data (CuK alpha 1,2 radiation), which were indexed using space group Cmca (64), with cell parameters a = 16.4749(1), b = 11.216 1 (1) and c = 11.4654(1). Crystal structure refinement was performed by means of Rietveld method, with the conventional factors R-wp = 19.2; R-exp = 14.40. Na2Li2Ti6O14 phase structure is described as a network of intercalated edge and comer-sharing distorted TiO6 octahedra. Na ions are surrounded by 11 oxygen atoms, while Ti and Li atoms maintain a coordination of 6 and 4, respectively. This arrangement provides tunnels along the z-axis, in which the lithium atoms are located, forming distorted tetrahedra. 2006-118 Goto, N Fujihisa, H Yamawaki, H Wakabayashi, K Nakayama, Y Yoshida, M Koshi, MAF Crystal structure of the high-pressure phase of hexahydro-1,3,5-trinitro-1,3,5-triazine (gamma-RDX) JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 23655-23659. The crystal structure of the high-pressure phase of hexahydro-1,3,5-trinitro-1,3,5-triazine (gamma-RDX), which is stable above 4 GPa at room temperature, was investigated by using infrared spectroscopy and powder X-ray diffraction measurements followed by Rietveld refinements using a diamond anvil cell (DAC). Although gamma and alpha phases were found to belong to the same space group Pbca, they exhibited a different crystal packing. The molecular structure of the gamma phase exhibited the same conformation as that of the alpha phase however, the torsion angles of N-NO2 changed marginally. 2006-119 Santamaria-Perez, D Haines, J Amador, U Moran, E Vegas, A Structural characterization of a new high-pressure phase of GaAsO4 ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 1019-1024. As in SiO2 which, at high pressures, undergoes the alpha-quartz -> stishovite transition, GaAsO4 transforms into a dirutile structure at 9 GPa and 1173 K. In 2002, a new GaAsO4 polymorph was found by quenching the compound from 6 GPa and 1273 K to ambient conditions. The powder diagram was indexed on the basis of a hexagonal cell (a = 8.2033, c = 4.3941 A, V = 256.08 A(3)), but the structure did not correspond to any known structure of other AXO(4) compounds. We report here the ab initio crystal structure determination of this hexagonal polymorph from powder data. The new phase is isostructural to beta-MnSb2O6 and it can be described as a lacunary derivative of NiAs with half the octahedral sites being vacant, but it also contains fragments of the rutile-like structure. 2006-120 Day, GM van de Streek, J Bonnet, A Burley, JC Jones, W Motherwell, WDS Polymorphism of scyllo-inositol: Joining crystal structure prediction with experiment to elucidate the structures of two polymorphs CRYSTAL GROWTH & DESIGN 6, 2006, 2301-2307. We report on the crystal structures of two polymorphs of scyllo-inositol. Crystallization of this inositol initially failed to yield a single crystal suitable for structure solution, so a computational prediction of the low-energy forms was performed in parallel with the crystallization experiments. When a single crystal was finally grown, its structure failed to explain the powder X-ray diffraction pattern of the bulk material, which seemed to show a mixture of polymorphs. With the aid of the lowest-energy predicted crystal structure from a lattice energy search and the DASH program for structure solution from powder data, we propose the structure of the second polymorph. The combined use of single-crystal structure solution, structure solution from powder diffraction data, and a lattice energy search for possible structures, which was necessary for the elucidation of the second polymorph of scylloinositol, demonstrates the synergy between experimental and computational studies of molecular organic materials. 2006-121 Berger, TG Leineweber, A Mittemeijer, EJ Sarbu, C Duppel, V Fischer, P On the formation and crystal structure of the Pd6B phase ZEITSCHRIFT FUR KRISTALLOGRAPHIE 221, 2006, 450-463. The crystal structure of the Pd6B phase has been elucidated employing selected-area electron diffraction and X-ray and neutron powder diffraction methods. It is based on a cubic close packed arrangement of Pd with B occupying 1/6 of the interstitial octahedral sites in an ordered way, such that a monoclinic (C2/c) superstructure results. The crystal structure contains isolated [BPd6] octahedral entities providing large distances between nearest neighbour boron atoms. Depending on the way of preparation, the same Pd6B phase can occur for the same composition in two different 'manifestations' having considerably different lattice parameters, which has a microstructural origin. Various phase equilibria between the ordered Pd6B phase and the disordered interstitial solid solution of boron in cubic close packed palladium have been investigated to clarify the corresponding regions in the phase diagram Pd-B. 2006-122 Wallwork, KS James, M Carter, ML The crystal chemistry, structure and properties of a synthetic carnotite-type compound, Ba-2[(UO2)(2)Ti2O8] CANADIAN MINERALOGIST 44, 2006, 433-442. The crystal structure of the carnotite-type compound Ba-2(UO2)(2)Ti2O8] has been determined by ab initio methods from synchrotron X-ray and neutron powder-diffraction data. We describe the first reported structure of a uranyl titanate; it was solved in the monoclinic space-group P2(1)/c and has the lattice parameters a 6.4463(1), b 8.5999(1), c 10.2532(1) angstrom, beta 75.936(1)degrees, V 551.36(1) angstrom(3), D-calc, 6.253 g/cm(3) and Z = 4. A multiple histogram approach was used to refine the structure from synchrotron and neutron-diffraction data, giving quality factors of R-B 0.032 and 0.039, R-wp 0.090 and 0.063, and R-p 0.070 and 0.049, respectively. The compound forms a layered structure in which sheets of uranyl pentagonal bipyramids share edges with dimers of TiO5 square pyramids. These are separated by layers of 11-fold-coordinated barium atoms. Because of the potential presence of Ba-2[(UO2)(2)Ti2O8] in ceramic waste-forms for the immobilization of radioactive wastes, the leach rate of uranium and barium were determined. The normalized rates of leaching from Ba-2[(UO2)(2)Ti2O8], averaged over seven days, are 1.3 X 10(-5) g/m(2) /day for uranium, a significantly lower rate than that observed from pyrochlore waste-forms, and 1 X 10(-4) g/m(2) /day for barium. 2006-123 Papoular, RJ Allouchi, H Dzyabehenko, AV Davydov, VA Rakhmanina, AV Boltalina, OV Seppelt, K Agafonov, V High-resolution X-ray powder diffraction structure determination of C60F48 FULLERENES NANOTUBES AND CARBON NANOSTRUCTURES 14, 2006, 279-285. Whereas previously reported X-ray powder diffraction experiments could be interpreted using an isotropic spherical two-shell model, our recently obtained data cannot. Rather, they were Rietveld-analyzed using three distinct anisotropic models for the C60F48 molecule featuring the S-6, D-3 and T-h molecular symmetries, respectively. The best fit was obtained for the D3 model, which is consistent with the F-19 NMR characterization of our sample. The chi(2) dependence upon the Euler angles of the (CF48)-F-60 molecule is found to be substantial. The unit 2006-124 Brugger, J Wallwork, KS Meisser, N Pring, A Ondrus, P Cejka, J Pseudojohannite from Jachymov, Musonoi, and La Creusaz: A new member of the zippeite-group AMERICAN MINERALOGIST 91, 2006, 929-936. Pseudojohannite is a hydrated copper(II) uranyl sulfate described from Jachymov, Northern Bohemia, Czech Republic (type locality). Pseudojobannite also occurs at the Musondi quarry near Kolwezi, Shaba, Congo, and the La Creusaz prospect, Western Swiss Alps. At all three localities. pseudojohannite formed through the interaction of acid sulfate mine drainage waters with uraninite (Jachymov and La Creusaz) or uranyl silicates (Musondi). Pseudojohannite forms moss green, non UV-fluorescent aggregates consisting of irregularly shaped crystals measuring up to 25 pm in length and displaying an excellent cleavage parallel to (1) over bar 01). d(meas) is 4.31 g/cm(3), d(calc) 4.38 g/cm(3). and the refractive indices are n(min) = 1.725 and n(max) = 1.740. A high-resolution synchrotron powder diffraction pattern on the material from Musondi shows that pseudojohannite is triclinic (P1 or P (1) over bar), with a = 10.027(1) angstrom, b = 10.822(1) angstrom, c = 13.396(1) angstrom, alpha = 87.97(1)degrees, beta = 109.20(1)degrees, gamma = 90.89(1)degrees, V = 1371.9(5) angstrom(3). The location of the uranium and sulfur atoms in the cell was obtained by direct methods using 1807 reflections extracted from the powder diffractogram. Pseudojohannite contains zippeite-type layers oriented parallel to ((1) over bar 01). The empirical chemical formula calculated for a total of 70 0 atoms is Cu6.52U7.85S4.02O70H55.74, leading to the simplified chemical formula Cu-6.5[(UO2)(4)O-4(SO4)(2)](2)(OH)(5)(.)25H(2)O. The distance of 9.16 angstrom between the uranylsulfate sheets in pseudojohannite shows that neighboring layers do not share 0 atoms with the same Cu Phi(6) [Phi = (O,OH)] distorted octahedrons, such as in magnesium-zippeite. Rather, it is expected that Cu Phi(6) forms a layer bound to the zippeite-type layers by hydrogen bonding, as in marecottite, or one apex of the Cu Phi(6)polyhedron only is shared with a zippeite-type layer, as in synthetic SZIPPMg. The higher number of cations in the interlayer of pseudojohannite (Cu:S = 1.6:1) compared to marecottite (3:4) and SZIPPMg (1: 1) indicates that pseudojohannite has a unique interlayer topology. Ab-initio powder structure solution techniques can be used to obtain important structural information on complex micro-crystalline minerals such as those found in the weathering environment. Pseudojohannite represents a new member of the zippeite group of minerals, and further illustrates the structural complexity of zippeite-group minerals containing divalent cations, which have diverse arrangements in the interlayer. Peudojohannite and other divalent zippeites are common, easily overlooked minerals in acid drainage environments around uranium deposits and wastes. 2006-125 Barnes, PW Lufaso, MW Woodward, PM Structure determination of A(2)M(3+)TaO(6) and A(2)M(3+)NbO(6) ordered perovskites: octahedral tilting and pseudosymmetry ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 384-396. The room-temperature crystal structures of six A(2)M(3+) M5+O6 ordered perovskites have been determined from neutron and X-ray powder diffraction data. Ba2YNbO6 adopts the aristotype high-symmetry cubic structure (space group Fm (3) over barm, Z = 4). The symmetries of the remaining five compounds were lowered by octahedral tilting distortions. Out-of-phase rotations of the octahedra about the c axis were observed in Sr2CrTaO6 and Sr2GaTaO6, which lowers the symmetry to tetragonal (space group = I4/ m, Z = 2, Glazer tilt system = a(0)a(0)c(-)). Octahedral tilting analogous to that seen in GdFeO3 occurs in Sr2ScNbO6, Ca2AlNbO6 and Ca2CrTaO6, which lowers the symmetry to monoclinic (space group P2(1)/ n, Z = 2, Glazer tilt system = a(-)a(-)c(+)). The Sr2MTaO6 (M = Cr, Ga, Sc) compounds have unit- cell dimensions that are highly pseudocubic. Ca2AlNbO6 and Ca2CrTaO6 have unit- cell dimensions that are strongly pseudo-orthorhombic. This high degree of pseudosymmetry complicates the space- group assignment and structure determination. The space-group symmetries, unitcell dimensions and cation ordering characteristics of an additional 13 compositions, as determined from X- ray powder diffraction data, are also reported. An analysis of the crystal structures of 32 A(2)MTaO(6) and A(2)MNbO(6) perovskites shows that in general the octahedral tilt system strongly correlates with the tolerance factor. 2006-126 Stahly, GP Bates, S Andres, MC Cowans, BA Discovery of a new polymorph of dehydroepiandrosterone (prasterone) and solution of its crystal structure from X-ray powder diffraction data CRYSTAL GROWTH & DESIGN 6, 2006, 925-932. A new polymorph of dehydroepiandrosterone, also known as DHEA or prasterone, was found and designated form FVI. Form FVI is anhydrous and nonsolvated, and is less thermodynamically stable than the known form FI under ambient conditions. The X-ray powder diffraction patterns of FI and FVI are so similar that this technique is inadequate to determine if samples contain pure FI, pure FVI, or mixtures of the two. However, the forms can be differentiated by solid-state NMR spectroscopy. The crystal structure of FVI was determined from X-ray powder diffraction data using a combination of proprietary SSCI software and the Cambridge Crystallographic Data Centre's program DASH. 2006-127 Vivani, R Costantino, F Costantino, U Nocchetti, M New architectures for zirconium polyphosphonates with a tailor-made open-framework structure INORGANIC CHEMISTRY 45, 2006, 2388-2390. The use of tetraphosphonic building blocks for the preparation of inorganic-organic zirconium derivatives has led to the formation of novel compounds with a modular structure. This is based on the different connection of polymeric 1 D inorganic units covalently connected by organic groups. The different kinds of connections generate two different open-framework structures. These structures have been solved "ab initio" by powder X-ray diffraction data. Very likely, the dimensions of the channels inside these structures may be tuned by the right choice of the interlinking organic group. 2006-128 Fernandez-Carrasco, L Rius, J Synthesis and crystal structure determination of hydrated potassium dawsonite from powder diffraction data EUROPEAN JOURNAL OF MINERALOGY 18, 2006, 99-104. During the optimisation of the synthesis conditions of non-hydrated potassium dawsonite, a compound which has been recently shown to be involved in the alkaline hydrolysis of calcium aluminate cement (CAC), a new closely related hydrated phase appearing below T = 25 degrees C was detected by powder X-ray diffraction. To gain a more complete understanding of the crystal chemistry of CAC, this new phase was synthesised in pure form and its crystal structure solved from powder X-ray diffraction data. The crystal data are a = 8.3312(4), b = 11.2670(5), c = 5.661(2)angstrom, Pna2(1) (No. 33) and the resulting chemical formula is KAl(CO3)(OH)(2)center dot H2O with Z = 4. From the refined positions of the non-hydrogen atoms and from the balance of bond valences, the chemical nature of the 0 atoms could be univocally established [R-wp = 0.132, R-B = 0.056, Chi(2) = 1.15]. The unit cell of this hydrated compound contains two carboaluminate chains formed by the basic unit [Al-2(OH)(4)(CO3)(2)](2-) propagating along the c axis and being stabilised by a complex H-bond network. The arrangement of these chains is similar to that found in dawsonite, so that the atomic positions of K+ and Na+ in both structures are also similar. As confirmed by the X-ray diffraction study of a one-year-old sample, hydrated potassium dawsonite slowly transforms into the non-hydrated form at room temperature. Due to the more favourable formation conditions, i.e. lower temperature and higher humidity, this hydrated phase could be eventually found in CAC pastes or mortars. 2006-129 Dorset, DL Weston, SC Dhingra, SS Crystal structure of zeolite MCM-68: A new three-dimensional framework with large pores JOURNAL OF PHYSICAL CHEMISTRY B 110, 2006, 2045-2050. The crystal structure of the aluminosilicate MCM-68 was solved from synchrotron powder diffraction data by the program FOCUS. The unit cell framework contains Si100.6Al11.4O224. This material crystallizes in space group P4(2)/mnm, where, after Rietveld refinement, a = 18.286(1) angstrom and c = 20.208(2) angstrom. A three-dimensional framework is found that contains continuous 12-ring channels and two orthogonal, intersecting, undulating 10-ring channels. Rietveld refinement of the model coordinates optimizes the framework geometry, to match the observed intensity profile by R-wp, = 0.1371, R(F-2) = 0.1411. It is not possible to determine the location of approximately 0.84 K+ cations remaining in the unit cell after the material is steamed and then dehydrated. The framework model also successfully predicts observed electron diffraction data in two projections, and the tetragonal projection can be determined independently from these data by direct methods. The calculated density of the framework structure is 1.66 g/cm(3), and the T-site framework density is 16.6 T/1000 angstrom(3). 2006-130 Gualtieri, AF Ferrari, S Galli, E Di Renzo, F van Beek, W Rietveld structure refinement of zeolite ECR-1 CHEMISTRY OF MATERIALS 18, 2006, 76-84. In this work, we present the structure refinement of ECR-1 to give the first direct evidence of the proposed structure of this synthetic zeolite. In fact, a model of the structure of ECR-1 was proposed on the basis of high-resolution transmission electron microscopy (HRTEM) evidence and the structure solution of the synthetic gallo-silicate TNU-7, but it has not been refined to date. The proposed model consists of structure layers of mordenite (MOR) and mazzite (MAZ) connected in a regular 1: 1 stacking sequence and framework topology EON. Because single crystals of ECR-1 cannot be synthesized, the structure was refined using the Rietveld method. High-resolution synchrotron powder diffraction data were collected on both the synthetic Na-ECR-1 and NH4-ECR-1 samples at ESRF. Na atoms located on the axis of the eight-member ring channels in mordenite and zeolite omega are not present in Na-ECR-1. In Na-ECR-1, the equivalent sites lay near the walls of the eight-membered-ring channels. This difference is presumably at the basis of the formation of ECR-1 because, during growth, the local symmetry deformation of the eight-membered-ring channel prevents the formation of the MOR or MAZ structures and justify the periodical shift from one structure to the other. A quantitative explanation of the anisotropic peak broadening observed in the powder patterns is also given. 2006-131 Paglia, G Bozin, ES Vengust, D Mihailovic, D Billinge, SJL Accurate structure determination of Mo6SyIz nanowires from atomic pair distribution function (PDF) analysis CHEMISTRY OF MATERIALS 18, 2006, 100-106. The structure of the recently discovered systematically reproducible Mo6SyI7 nanowires has been determined from the atomic pair distribution function (PDF) analysis of powder X-ray diffraction data. This total scattering approach was required because the nanowires are not perfectly crystalline and, therefore, the structure cannot be obtained crystallographic ally. Several nanotube and nanowire models were fit to the PDF data. The resulting best-fit model structure consists of nanowires Of Mo-6 octahedra that are bridged by sulfur and terminated on the outside by iodine. This demonstrates the power of total scattering methods in accurately resolving structural issues in nanostructured materials where traditional crystallographic methods fail. 2006-132 Giunchi, G Malpezzi, L Masciocchi, N A new crystalline phase of the boron-rich metal-boride family: the Mg2B25 species SOLID STATE SCIENCES 8, 2006, 1202-1208. A new complex magnesium boride, the Mg2B25 species, has been prepared and its crystal structure determined from laboratory X-ray powder diffraction data by the simulated annealing technique, followed by a conventional Rietveld refinement procedure. The title compound is R-centered trigonal (with a = 11.0402(3) angstrom and c = 24.198(1) angstrom, hexagonal setting), space group R-3m, and is isomorphous with beta-boron and with the rhombohedral compounds of the boron-rich metal-boride family. The magnesium atoms occupy interstitial sites with partial occupancies which can be interpreted with the aid of the analysis of "forbidden" interatomic Mg-Mg contacts. The Mg atom in the F site is vicariant with the B(4) atom and falls into a pseudometallocenic environment with the 10 nearest-neighbour B atoms; all other magnesium atoms are placed in lattice cavities within corrugated slabs normal to c, with Mg(D) and Mg(E) occupying sites already known to be populated in other metal borides, and Mg(N) in a new one. These slabs present two equiprobable, but self excluding, configurations of ordered Mg atoms, which randomly stack along the c-axis. Mg2B25 shows a significant increase of the c-axis of the rhombohedral lattice with respect to the other members of the family, which we attribute both to the larger metallic radius of Mg, vs. those of 3d transition metal atoms and to the anisotropic stacking of the Mg atoms, and, possibly, to the presence of the rather stuffed Mg sublattices. 2006-133 Masciocchi, N Galli, S Alberti, E Sironi, A Di Nicola, C Pettinari, C Pandolfo, L Synthesis, solid-state NMR, and X-ray powder diffraction characterization of group 12 coordination polymers, including the first example of a C-mercuriated pyrazole INORGANIC CHEMISTRY 45, 2006, 9064-9074. Cadmium and mercury acetates have been reacted with pyrazole (Hpz) and 3,5-dimethylpyrazole (Hdmpz), affording distinct mixed-ligand species, selectively prepared upon slightly modifying the reaction conditions. Two polymorphs of [{Cd(mu-ac)(2)(Hpz)(2)}(n)], as well as the [{Cd(mu-ac)(2)(Hdmpz)(2)}(n)] species (Hac = acetic acid), were obtained by solution chemistry, while the two-dimensional [{Cd-3(mu(3)-ac)(4)(mu-pz)(2)(Hpz)(2)}(n)] and [{Cd(mu-ac)(mu-pz)}(n)] polymers were prepared upon controlled thermal treatment of one of the [{Cd(mu-ac)(2)(Hpz)(2)}(n)] forms. Two mercury derivatives, [{Hg-3(mu-ac)(3)(mu-pz)(3)}(n)] and [{Hg(ac)(mu-dmpz)}(n)], were also prepared, the latter containing one-dimensional chains of Hg(II) ions bridged by C-mercuriated Hdmpz ligands. All their crystal structures (but one) were determined by powder diffraction methods using conventional X-ray laboratory equipment, supported by C-13 CPMAS NMR measurements. The latter method helped in assigning a C-metalated nature to an amorphous material of [Hg(ac)-( pz)] formula, obtained by employing EtOH as a solvent. A few other Hdmpz-containing cadmium acetates were also prepared, but their polyphasic nature, evidenced by diffraction methods, hampered their complete structural characterization. 2006-134 Navarro, JAR Barea, E Salas, JM Masciocchi, N Galli, S Sironi, A Ania, CO Parra, JB H-2, N-2, CO, and CO2 sorption properties of a series of robust sodalite-type microporous coordination polymers INORGANIC CHEMISTRY 45, 2006, 2397-2399. H-2, N-2, CO, and CO2 are readily incorporated in the porous, 3D sodalitic frameworks of coordination polymers of the [ML2](n) type, with M = Pd-II or Cu-II and HL = 2-hydroxypyrimidine or 4-hydroxypyrimidine. The metal ion and ligand functionalization modulate their sorption properties, making these materials suitable for gas storage and separation purposes. 2006-135 Barbier, J Cranswick, LMD The non-centrosymmetric borate oxides, MBi2B2O7 (M = Ca, Sr) JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3958-3964. Two novel noncentrosymmetric berates oxides, MBi2B2O7 or MBi2O(BO3)(2) (M=Ca, Sr), have been synthesized by solid-state reactions in air at temperatures in the 600-700 degrees C range. Their crystal structures have been determined ab initio and refined using powder neutron diffraction data. CaBi2B2O7 crystallizes in the orthorhombic Pna2(1) space group with a = 8.9371(5)angstrom, b = 5.4771(3)angstrom, c = 12.5912(7) angstrom, Z = 4, R-wp = 0.118, chi(2) = 2.30, SrBi2B2O7 crystallizes in the hexagonal P6(3) space group with a = 9.1404(4) angstrom, c = 13.0808(6) angstrom, Z = 6, R-wp = 0.115, chi(2) = 4.15. Large displacement parameters suggest the presence of disorder in SrBi2B2O7 as also revealed by diffuse 2 x a superstructure reflections in electron diffraction patterns. Both structures are built of identical (001) neutral layers of corner-sharing BO3 triangles and MO6 trigonal prisms forming six-membered rings in which Bi2O groups are located. Adjacent layers are stacked in a staggered configuration and connected through weak Bi-O bonds. A moderate efficiency for second harmonic generation (SHG) has been measured for a powder sample of CaBi2B2O7 (d(eff) = 2d(eff)(KDP)). reserved. FOX, Fullprof 2006-136 Tobbens, DM Kahlenberg, V Gspan, C Kothleitner, G Atomic and domain structure of the low-temperature phase of barium metagermanate (BaGeO3) ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 62, 2006, 1002-1009. The crystal structure of the low-temperature form of barium metagermanate (BaGeO3) has been determined from laboratory X-ray powder diffraction data collected at 298.5 (5) K. The structure was found to consist of alternating layers of Ba cations and [GeO3](3) rings, and is closely related to pseudowollastonite. The rings show a twofold positional disorder owing to stacking faults. The stacking is not random, but can be rationalized by a twinning mechanism mapping the two non-congruent enantiomorphic polytypes of the structure onto each other. This model also explains the diffuse scattering and twinning observed in SAED and HRTEM, as well as the size and strain-like broadening effects found in the XRPD pattern. FOX 2006-137 Tobbens, DM Kaindl, R Kahlenberg, V Schottenberger, H Hummel, M The homoleptic square-antiprismatic chelate tetrakis(3-acetyl-2,4-pentanedionato)zirconium(IV): A promising coordination motif for tetrahedral metal-organic frameworks CRYSTAL GROWTH & DESIGN, 6, 2006, 1720-1725. The novel analogue of the parent Zr(acac)(4) complex, tetrakis(3-acetyl-2,4-pentanedionato) zirconium(IV), Zr[C7O3H9](4), has been synthesized straightforwardly by a salt-free methodology and was characterized by a number of complementary methods (H-1 NMR, C-13 NMR, IR, and bulk density). From polycrystalline material, X-ray powder diffractograms and micro-Raman spectra were obtained and are discussed in detail. The crystal structure was determined from laboratory X-ray powder diffraction data by simulated annealing and subsequently refined with the Rietveld technique. The compound is monoclinic with space group P2/c. Zr, residing on a crystallographic 2-fold rotation axis, is coordinated by the four chelating ligands forming a square-antiprismatic coordination polyhedron. Differences and similarities to zirconium(IV) acetylacetonate, Zr[C5O2H7](4), and other similar complexes are discussed, addressing the conformational rigidity of this symmetrically substituted homoleptic acac complex. FOX 2006-138 2005-1 Beckmann, J Costantino, F Dakternieks, D Duthie, A Ienco, A Midollini, S Mitchell, C Orlandini, A Sorace, L Inorganic-organic hybrids of the p,p '-diphenylmethylenediphosphinate, pcp(2-). Synthesis, characterization, and XRPD structures of [Sn(pcp)] and [Cu(pcp)] INORGANIC CHEMISTRY 44, 2005, 9416-9423. Two new inorganic-organic polymeric hybrids [Sn(pcp)] and [Cu(pcp)], pcp = CH2(PhPO2)(2)(2-), solved "ab initio" by X-ray powder diffraction (XRPD) data. TREOR 2005-2 Vila, E Iglesias, JE Galy, J Castro, A Synthesis and characterization of a novel bismuth-molybdenum oxide and study of its ionic conducting behavior SOLID STATE SCIENCES Bi10Mo3O24. The crystal data have been determined by ab initio indexing of the powder pattern. TREOR 2005-3 Bestaoui, N Xiang, OY Fredoueil, F Bujoli, B Clearfield, A Structural characterization of Cd-3(O3PC2H4CO2) (2). 2H(2)O from in-house X-ray powder data and NMR ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 669-674. poly[[bis(mu-2-carboxylatoethylphosphonato)cadmium] dihydrate], Cd-3(O3PC2H4CO2)(2) . 2H(2)O, structure determined from in-house powder data. The structure was solved in both P2(1)/c and P2(1) space groups. TREOR 2005-6 Burley, JC Structure and intermolecular interactions of glipizide from laboratory X-ray powder diffraction ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE, 61, 2005, 710-716. The crystal structure of glipizide, used as a major treatment of type-2 diabetes, has been determined ab initio using variable-temperature laboratory X-ray powder diffraction combined with a direct-space Monte Carlo/simulated annealing methodology. The strengths of the intermolecular interactions (van der Waals, pi-pi stacking, hydrogen bonding and steric interlock) were quantitatively estimated using the thermal expansion data, which were collected in the same set of experiments as those used to determine the structure. TREOR, DICVOL 2005-7 ?? Rodriguez, A Sakiyama, H Masciocchi, N Galli, S Galez, N Lloret, F Colacio, E Hexacyanocobaltate(III) anions as precursors of Co(II)-Ni(II) cyano-bridged multidimensional assemblies: Hydrothermal syntheses, crystal and powder x-ray structures, and magnetic properties INORGANIC CHEMISTRY 44, 2005, 8399-8406. unconventional powder X-ray diffraction analyses TREOR 2005-8 Bonhomme, F Alam, TM Celestian, AJ Tallant, DR Boyle, TJ Cherry, BR Tissot, RG Rodriguez, MA Parise, JB Nyman, M Tribasic lead maleate and lead maleate: Synthesis and structural and spectroscopic characterizations INORGANIC CHEMISTRY 44, 2005, 7394-7402. [Pb4O3]C2H2(CO2)(2)(.)1/2H(2)O, solved ab initio from X-ray powder diffraction data, TREOR 2005-9 Barbier, J Penin, N Denoyer, A Cranswick, LMD BaBiBO4, a novel non-centrosymmetric borate oxide SOLID STATE SCIENCES 7, 2005, 1055-1061. BaBiBO4 or BaBi(BO3)O, Pna2(1) crystal structure determined from powder X-ray diffraction data and refined from powder neutron diffraction data TREOR 2005-10 Kelm, K Mader, W Synthesis and structural analysis of epsilon-Fe2O3 ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 2383-2389 epsilon-Fe2O3 Pna2(1) ab initio, X-ray diffraction data of the powder containing small amounts of Al substituting Fe were refined by the Rietveld method. TREOR 2005-11 Fukuda, K Fukushima, K Crystal structure of hexagonal SrAl2O4 at 1073 K OURNAL OF SOLID STATE CHEMISTRY 178, 2005, 2709-2714 SrAl2O4 at 1073 K - P63 , Z = 6 determined from conventional X-ray powder diffraction data using direct methods, refined by the Rietveld method. The structure was hexagonal TREOR 2005-12 Bhuvanesh, NSP Reibenspies, JH Zhang, YG Lee, PL A novel strategy for ab initio structure determination using micro-powder X-ray diffraction: structure solution and refinement of 3-bromophenylboronic acid and tris(4-bromophenyl) boroxine JOURNAL OF APPLIED CRYSTALLOGRAPHY 38, 2005, 632-638. 3-bromo-phenylboronic acid and tris(4-bromophenyl) boroxine, were recorded with microgram quantities of sample using a recently developed method employing nylon loops with synchrotron radiation and an image-plate detector. The structures of the two compounds have been solved by ab initio methods using real-space techniques ( simulated annealing and/or parallel tempering) followed by Rietveld refinements with soft restraints on the bond lengths of the rigid bodies. It is believed that this is the first time that powder X-ray diffraction patterns using microgram samples have been successfully employed for the structure solution and refinement of molecules with reasonable complexity. TREOR, DICVOL, 2005-13 Zhang, Y Liu, QL Li, JB Liang, JK Luo, J Liu, FS Xiao, YG Rao, GH Structures of the zeta and zeta ' phases in the Ag-Ga system JOURNAL OF ALLOYS AND COMPOUNDS 399 (2005) 155-159. zeta-phase P63/mmc and zeta'-phase : Ag2Ga (real composition Ag2+xGa1-x, x = 0.16) P-6 determined by X-ray powder diffraction and refined by Rietveld method. TREOR 2005-14 Lefebvre, J Willart, JF Caron, V Lefort, R Affouard, F Danede, F Structure determination of the 1/1 alpha/beta mixed lactose by X-ray powder diffraction ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 455-463. mixed form of alpha/beta lactose The X-ray powder diffraction pattern was recorded at room temperature with a sensitive curved detector (CPS 120). The structure was solved by real-space methods ( simulated annealing) followed by Rietveld refinements with soft constraints on bond lengths and bond angles. The width of the Bragg peaks is interpreted through a microstructural approach in terms of isotropic strain effects and anisotropic size effects. TREOR 2005-15 Zhang, QA Yang, WM Akiba, E Synthesis and crystal structure of a new ternary compound Ca4Al3Mg JOURNAL OF ALLOYS AND COMPOUNDS 398, 2005, 123-126. Ca4Al3Mg Pbcm The crystal structure was determined by X-ray powder diffraction. TREOR 2005-16 Fukuda, K Moriyama, A Iwata, T Crystal structure, phase transition and anisotropic thermal expansion of barium zirconium diorthophosphate, BaZr(PO4)(2) JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 2144-2151. BaZr(PO4)(2) at 298 K C2/m Z = 2 determined from conventional X-ray powder diffraction data using direct methods, and it was further refined by the Rietveld method. TREOR 2005-17 Tsirlin, AA Chernaya, VV Shpanchenko, RV Antipov, EV Hadermann, J Crystal structure and properties of the new complex vanadium oxide K2SrV3O9 MATERIALS RESEARCH BULLETIN 40, 2005, 800-809. K2SrV3O9 Pnma and Z = 4. investigated by means of X-ray powder diffraction (XPD) refined by Rietveld method using X-ray powder diffraction data. TREOR 2005-18 Salvado, MA Pertierra, P Bortun, AI Trobajo, C Garcia, JR New hydrothermal synthesis and structure of Th-2(PO4)(2)(HPO4)-H2O: the first structurally characterized thoriurn hydrogenphosphate INORGANIC CHEMISTRY Th-2(PO4)(2)(HPO4)-H2O P21, Z = 2 solved by powder X-ray diffraction data TREOR 2005-19 Shin, N Kim, J Ahn, D Sohn, KS A new strontium borophosphate, Sr6BP5O20, from synchrotron powder data ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 61, 2005, 154-156. Strontium borophosphate, Sr6BP5O20, was prepared by a solution synthesis method. The crystal structure was solved ab initio from synchrotron powder data without preliminary knowledge of the chemical formula. The compound crystallizes in space group I (4) over bar c2. Sr atoms occupy sites coordinated by eight or nine O atoms, and the anionic layer consists of BO4 and PO4 tetrahedra. The eightfold-coordinated Sr atom lies at a site with twofold symmetry, while one P atom and the B atom are located on special positions of site symmetry (4) over bar. TREOR, DICVOL 2005-20 Stahl, K Balic-Zunic, T da Silva, F Eriksen, KM Berg, RW Fehrmann, R The crystal structure determinations and refinements of K2S2O7, KNaS2O7 and Na2S2O7 from X-ray powder and single crystal diffraction data JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 1697-1704. K2S2O7, C2/c and KNaS2O7 solved and/or refined from X-ray synchrotron powder diffraction data TREOR 2005-21 Malpezzi, L Magnone, GA Masciocchi, N Sironi, A Single crystal and powder diffraction characterization of three polymorphic forms of Acitretin JOURNAL OF PHARMACEUTICAL SCIENCES 94, 2005, 1067-1078. Polymorphs of Acitretin : [all-trans-9-(4-methoxy-2,3,6-trimethylphenyl)-3,7-dimethyl-2,4,6,8-nona tetraenoic acid or 3-methoxy-2-methyl-17-nor-1,2,3,4-tetradehydroretinoic acid], three polymorphic modifications (hereafter, I, II, and III), TREOR X-ray powder diffraction methods (form II and III) from conventional laboratory data only. real space techniques (simulated annealing and whole-profile pattern matching) have been employed. These results show that ab initio structural studies from conventional laboratory X-ray powder diffraction (XRPD) data are fully providing the opportunity to investigate the structural aspects of moderately complex substances also in the absence of single crystals, disclosing the crystal chemistry of a few polymorphs of pharmaceutically relevant species. TREOR 2005-22 Bestaoui, N Bakhmutova-Albert, EV Rodriguez, AV Llavona, R Clearfield, A Ab-initio powder structure determination of dichloro[1,2ethanediylbis(iminomethylene)bis(phosphonato)]trizinc dihydrate EUROPEAN JOURNAL OF INORGANIC CHEMISTRY iss 5, 2005, 829-836. dichloro[1,2-ethanediylbis(iminomethylene)bis(phosphonato)]trizinc dihydrate, Zn3Cl2(HO3PCH2NHCH2CH2NHCH2PO3H)(2) . 2H(2)O P2(1)/n, Z = 4. The crystal structure was determined ab initio from its powder pattern using the programs EXPO and GSAS. TREOR 2005-23 Fernandez-Carrasco, L Puertas, F Blanco-Varela, MT Vazquez, T Rius, J Synthesis and crystal structure solution of potassium dawsonite: An intermediate compound in the alkaline hydrolysis of calcium aluminate cements CEMENT AND CONCRETE RESEARCH 35, 2005, 641-646. Potassium dawsonite KAI(CO3)(OH)2 Cmcm Z = 4. has been solved by direct methods from X-ray powder diffraction data and refined with the Rietveld method. TREOR 2005-24 Ribas, X Sironi, A Masciocchi, N Lopes, EB Almeida, M Veciana, J Rovira, C Structural, magnetic, and electrical characterization of new polycrystalline phases of nickel- and platinum-doped [(DT-TTF)n][Au(mnt)(2)] (n=1,2) INORGANIC CHEMISTRY 44, 2005, 2358-2366. determined using laboratory X-ray powder diffraction data. TREOR 2005-25 Baies, R Caignaert, V Pralong, V Raveau, B Copper hydroxydiphosphate with a one-dimensional arrangement of copper polyhedra: Cu-3[P2O6OH](2) INORGANIC CHEMISTRY 44, 2005, 2376-2380. Cu-3(P2O6OH)(2) P1 solved ab initio from X-ray powder diffraction data TREOR 2005-26 Lu, J Wei, S Yu, WC Zhang, HB Qian, YT TStructure and luminescence of 2D dilute magnetic semiconductors: Cd1-xMnxSe . L-0.5 (L = diamines) CHEMISTRY OF MATERIALS 17, 2005, 1698-1703. The two-dimensional (2D) dilute magnetic semiconductors (Cd1-xMnxSeL0.5)-L-. (L = ethylenediamine, or en, and 1,6-hexanediamine, or hda, x = 0-0.8) were synthesized in an autoclave at 120 degrees C. Ab initio structure solution from X-ray powder diffraction reveals the host compound CdSe . hda(0.5) (space group, Pbca, a = 6.8852 angstrom, b = 6.7894 angstrom, c = 27.4113 angstrom) is structurally analogous to CdSe . en(0.5), except for a subtle difference in alignment of aliphatic diamine ligands-the hda molecule deflects from the c axis and inclines toward the b axis. TREOR 2005-27 Bonhomme, F Larentzos, JP Alam, TM Maginn, EJ Nyman, M Synthesis, structural characterization, and molecular modeling of dodecaniobate Keggin chain materials INORGANIC CHEMISTRY 44, 2005, 1774-1785. Four new isostructural one-dimensional dodecaniobate Keggin materials, Na-12[Ti2O2][TNb1 2O40]-xH(2)O and Na-10[Nb2O2][TNb12O40]-xH(2)O with T = (Si or Ge), have been synthesized hydrothermally using a Lindqvist-ion salt, Na-7 [Nb6O19H]-15H(2)O, as the precursor. Their structure, consisting of chains of Keggin ions [TNb12O40](16-) linked by [Ti2O2](4+) or [Nb2O2](6+) bridges, was solved ab initio from powder diffraction data. TREOR 2005-28 Gallo, E Caselli, A Ragaini, F Fantauzzi, S Masclocchi, N Sironi, A Cenini, S Structural determination of ruthenium-porphyrin complexes relevant to catalytic epoxidation of olefins INORGANIC CHEMISTRY 44, 2005, 2039-2049 A reproducible synthesis of a competent epoxidation catalyst, [Ru-VI(TPP)(0)(2)] (TPP = tetraphenylporphyrin dianion), starting from [Ru-II(TPP)(CO)L] (L = none or CH3OH), is described. The molecular structure of the complex was determined by using ab initio X-ray powder diffraction (XRPD) methods TREOR 2005-29 Boldyreva, EV Ivashevskaya, SN Sowa, H Ahsbahs, H Weber, HP Effect of hydrostatic pressure on the gamma-polymorph of glycine - 1. A polymorphic transition into a new delta-form ZEITSCHRIFT FUR KRISTALLOGRAPHIE 220, 2005, 50-57. The results of a high-resolution powder diffraction study of the effect of high hydrostatic pressure up to 8 GPa on the pure gamma-polymorph of glycine (P3(1)) are discussed. A phase transition with a jumpwise change of cell volume and cell parameters was observed. The transition starts at about 2.73 GPa and is still not complete even at 7.85 GPa. The crystal structure of the previously unknown high-pressure polymorph of glycine (delta-polymorph) could be solved and refined in the space group Pn. TREOR 2005-30 Platteau, C Lefebvre, J Affouard, F Willart, JF Derollez, P Mallet, F Structure determination of the stable anhydrous phase of alpha-lactose from X-ray powder diffraction ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 185-191. The stable anhydrous form of alpha-lactose has been obtained by the dehydration of alpha-lactose monohydrate in methanol. An Xray powder diffraction pattern was recorded at room temperature with a laboratory diffractometer equipped with an INEL curved sensitive detector CPS120. The starting structural model of this form was found by a Monte-Carlo simulated annealing method. TREOR 2005-31 Barea, E Romero, MA Navarro, JAR Salas, JM Masciocchi, N Galli, S Sironi, A Structure, spectroscopic properties, and reversible solid-to-solid reactions of metal complexes of 5-nitro-pyrimidin-2-olate INORGANIC CHEMISTRY 44, 2005, 1472-1481. In searching for coordination polymers containing the highly polarized 5-nitro-pyrimidin-2-olate ligand (NP), a number of species containing 3d transition metals have been prepared and characterized, namely Co(NP)(2)(H2O)(4), [Co(NP)(2)](n), Ni(NP)(2)(H2O)(4), Ni(NP)(2)](x), and [Zn(NP)(2)](n). Their structures have been determined by X-ray powder diffraction methods. TREOR 2005-32 Ivashkevich, LS Lyakhov, AS Ivashkevich, DO Degtyarik, MM Gaponik, PN Synthesis and crystal structure of the catena-poly[[bis(1-methyltetrazole-N-4)copper(II)]-di-mu-chloro] complex CuCl2(C2H4N4)(2) RUSSIAN JOURNAL OF INORGANIC CHEMISTRY 50, 2005, 78-82 The X-ray diffraction study of the CuCl2(C2H4N4)(2) complex, where C2H4N4 is 1-methyl-tetrazole, was carried out. The structure was solved ab initio using the X-ray powder diffraction data. The complex crystallizes in space group P2(1)/c, alpha = 11.2341(6) Angstrom, b = 6.7272(3) Angstrom, c = 7.2149(3) Angstrom, 104.718(3)degrees, V 527.36(4) Angstrom(3), Z = 2. TREOR 2005-33 Ivashkevich, LS Lyakhov, AS Degtyarik, MM Gaponik, PN An X-ray powder diffraction study of catena-poly[[bis(1-methyl-1H-tetrazole-kappa N-4)copper(II)]-di-mu-bromo] ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE, 61, 2005, M394-M396. The crystal structure of the polymeric title complex, [CuBr2(C4H8N8)(2)](n), has been solved from X-ray powder data and refined with the Rietveld method using geometrical soft restraints. TREOR 2005-34 Chernaya, VV Mitiaev, AS Chizhov, PS Dikarev, EV Shpanchenko, RV Antipov, EV Korolenko, MV Fabritchnyi, PB Synthesis and investigation of Tin(II) pyrophosphate Sn2P2O7 CHEMISTRY OF MATERIALS 17, 2005, 284-290. The crystal structure of the high temperature alpha-Sn2P2O7 form was solved using high-temperature powder diffraction data collected at 773 K. The structural motif of the high temperature form (monoclinic, P2(1)/n, a = 7.1765(4) Angstrom, b = 9.2874(6) Angstrom, c = 5.2968(4) Angstrom, beta = 106.034(3)degrees, V = 339.30(5) Angstrom(3), Z = 2) is closely related to the room temperature modification. TREOR 2005-35 Platteau, C Lefebvre, J Hemon, S Baehtz, C Danede, F Prevost, D Structure determination of forms I and II of phenobarbital from X-ray powder diffraction ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 80-88. From pure powders of forms I and II of phenobarbital, X-ray diffraction patterns were recorded at room temperature. The starting crystal structural models were found by a Monte-Carlo simulated annealing method. The structures of the two forms were obtained through Rietveld refinements. Soft restraints were applied on bond lengths and bond angles, all H-atom positions were calculated. The cell of form I is monoclinic with the space group P2(1)/n, Z = 12, Z' = 3. Form II has a triclinic cell, with the space group P (1) over bar, Z = 6, Z' = 3. For both forms, the crystal cohesion is achieved by networks of N - H ... O hydrogen bonds along [101]. The broadening of the Bragg peak profiles is interpreted in terms of isotropic strain effects and anisotropic size effects. TREOR 2005-36 Derollez, P Correia, NT Danede, F Capet, F Affouard, F Lefebvre, J Descamps, M Ab initio structure determination of the high-temperature phase of anhydrous caffeine by X-ray powder diffraction ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 329-334. The high-temperature phase I of anhydrous caffeine was obtained by heating and annealing the purified commercial form II at 450 K. This phase I can be maintained at low temperature in a metastable state. A powder X-ray diffraction pattern was recorded at 278 K with a laboratory diffractometer equipped with an INEL curved position-sensitive detector CPS120. Phase I is dynamically orientationally disordered (the so-called plastic phase). The Rietveld refinements were achieved with rigid-body constraints. It was assumed that on each site, a molecule can adopt three preferential orientations with equal occupation probability. Under a deep undercooling of phase I, below 250 K, the metastable state enters in a glassy crystal state. N-TREOR 2005-37 Jorda, JL Prokic, S McCusker, LB Baerlocher, C Xue, CF Jong, JX Synthesis and structure analysis of the potassium calcium silicate CAS-1. Application of a texture approach to structure solution using data collected in transmission mode COMPTES RENDUS CHIMIE 8, 2005, 331-339. The crystal structure of the potassium calcium silicate material, CAS-1 (&VERBAR;(Ca4K4(H2O)(8))&VERBAR;[Si16O38]), has been determined from synchrotron powder diffraction data collected on a textured polycrystalline sample. It was not possible to solve the structure directly from normal high-resolution powder diffraction data, so the newly developed texture approach to structure solution using data collected in transmission mode was applied. Data analysis was performed using the computer program Expol, which has been developed to handle the large amount of data generated in transmission mode. The structure could then be solved by direct methods, and Rietveld refinement (using data collected on an untextured sample) converged with R-F = 0.062 and R-wp = 0.175 (R-exp = 0.097). This structure is the first novel structure to be solved using the texture method in this configuration. As suggested by Si-29 MAS NMR results (1 Q(4) and 3 Q(3) signals, all of equal intensity), CAS-1 (C2, a = 24.158 &ANGS;, b = 7.016 &ANGS;, c = 6.482 &ANGS;, β = 95.19&DEG;) proved to be a layer silicate. The structure can be described as a series of silicate double layers connected via chains of edge-sharing CaO5(H2O) octahedra. There is a two-dimensional eight-ring channel system within the silicate layer, and K+ ions, which balance the charge, are located in the eight-rings of the two 4.8(2) nets that form the double layer. One water molecule is located in the channel system and another bridges between K+ and Ca2+ ions. The structure is related to that of the natural mineral rhodesite. 2005-38 ?? Anillo, A Altomare, A Moliterni, AGG Bauer, EM Bellitto, C Colapietro, M Portalone, G Righini, G Hydrothermal synthesis, structural characterization and magnetic studies of the new pillared microporous ammonium Fe(III) carboxyethylphosphonate: [NH4][Fe-2(OH){O3P(CH2)(2)CO2}(2)] JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 306-313. The preparation by hydrothermal reaction and the crystal structure of the iron(III) carboxyethylphosphonate of formula [NH4][Fe-2(OH){O3P(CH2)(2)CO2}(2)] is reported. The green-yellow compound crystallizes in the monoclinic system, space group Pc(n.7), with the following unit-cell parameters: a = 7.193(3) A, b = 9.776(3) A, c = 10.17(4) A and beta = 94.3(2)degrees. It shows a typical layered hybrid organic-inorganic structure featuring an alternation of organic and inorganic layers along the a-axis of the unit cell. The bifunctional ligand [O3P(CH2)(2)CO2](3-) is deprotonated and acts as a linker between adjacent inorganic layers, to form pillars along the a-axis. The inorganic layers are made up of dinuclear Fe(III) units, formed by coordination of the metal ions with the oxygen atoms originating from the [O3P-](2-) end of the carboxyethylphosphonate molecules, the oxygen atoms of the [-CO2](-) end group of a ligand belonging to the adjacent layer and the oxygen atom of the bridged OH group. Each Fe(III) ion is six-coordinated in a very distorted octahedral environment. Within the dimer the Fe-Fe separation is found to be 3.5 A, and the angle inside the [Fe(1)-O(11)-Fe(2)] dimers is similar to124degrees. The resulting 3D framework contains micropores delimited by four adjacent dimers in the (bc) planes of the unit cell. These holes develop along the a-direction as tunnel-like pores and [NH4](+) cations are located there. The presence of the p-hydroxo-bridged [Fe(1)-O(11)-Fe(2)] dimers in the lattice is also responsible for the magnetic behavior of the compound at low temperatures. The compound contains Fe3+ ions in the high-spin state and the two Fe(III) ions are antiferromagnetic coupled. The J/k value of -16.3 K is similar to those found for other mu-hydroxo-bridged Fe(III) dimeric systems having the same geometry. N-TREOR 2005-39 Muhle, C Karpov, A Jansen, M Crystal structure elucidation of anhydrous Rb-2[Pt(CN)(4)] from X-ray powder diffraction data ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 60, 2005, 1269-1272. The title compound has been synthesized by metathesis of Ba[Pt(CN)(4)].4 H2O with Rb2SO4, in aqueous solution. Its crystal structure was solved from X-ray powder diffraction data using the simulated-annealing approach, and refined by Rietveld's method. The compound crystallizes in space group Imma, a = 11.1432(2), b = 7.4382(1), c = 11.1896(2) angstrom, V = 927.45(3) angstrom(3), Z = 4, R-P = 0.0402, R-W = 0.0247 (N-hkl = 173). Square-planar tetracyanoplatinate groups stack in an unprecedented eclipsed conformation, forming one-dimensional linear chains of Pt-atoms with Pt-Pt separations of 3.719 angstrom. Rb-2[Pt(CN)(4)] was characterized by differential thermal analysis, thermo-gravimetry and infrared spectroscopy. DICVOL 2005-40 Ramirez-Cardona, M Ventola, L Calvet, T Cuevas-Diarte, MA Rius, J Amigo, JM Reventos, MM Crystal structure determination of 1-pentanol from low-temperature powder diffraction data by Patterson search methods POWDER DIFFRACTION 20, 2005, 311-315. In the course of our research on normal alkanols, the crystal structure of 1-pentanol has been solved by applying Patterson-search methods to laboratory powder X-ray diffraction data recorded on a curved position-sensitive detector (CPS120) at 183 K. The crystal structure was refined with the rigid-body Rietveld least-squares method. The cell is monoclinic, space group P2(1)/c, Z=4, and the cell parameters are a = 15.592(9) angstrom, b=4.349(1) angstrom, c=9.157(1) angstrom, beta = 104.7(7)degrees, V=600.6(3) angstrom(3). There is one molecule in the asymmetric unit with the O-H bond in gauche conformation with respect to the alkyl skeleton. Packing is defined by the hydrogen bonds linking the 1-pentanol molecules along zigzag chains parallel to b. DICVOL 2005-41 Pan, ZG Cheung, EY Harris, KDM Constable, EC Housecroft, CE Structural properties of methoxy derivatives of benzyl bromide, determined from powder X-ray diffraction data POWDER DIFFRACTION 20, 2005, 345-352. Structure determination of 3,5-dimethoxybenzyl bromide and 3,4,5-trimethoxybenzyl bromide has been carried out from laboratory powder X-ray diffraction data using the direct-space Genetic Algorithm technique for structure solution followed by Rietveld refinement. These two compounds are of interest for their potential use as building blocks for the synthesis of dendritic materials. Although the two molecules differ only in the presence/absence of the methoxy group at the 4-position of the aromatic ring, the structural properties of the two materials are significantly different. (C) 2005 International Centre for Diffraction Data. DICVOL 2005-42 Grzechnik, A Dmitriev, V Weber, HP Dilithium zirconium hexafluoride Li2ZrF6 at high pressures: A new monoclinic phase JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 66, 2005, 1769-1774. Dilithium zirconium hexafluoride, Li2ZrF6 (P31m, Z = 1), is studied at high pressures using synchrotron angle-dispersive X-ray powder diffraction in a diamond anvil cell at room temperature. At atmospheric conditions, it has a structure with all the cations octahedrally coordinated to fluorine atoms. Above 10 GPa it transforms reversibly to a new polyrnorph (C2/c, Z = 4), in which the coordination polyhedron of the Zr atorns is a distorted square antiprism, while the Li atoms are in the octahedral coordination. The LiF6 octahedra form layers parallel to (100) that are connected by zig-zag chains of the edge-sharing Zr polyhedra running in the [001] direction. The relative change in volumes per one formula unit for both polymorphs is 6% at 11.8 GPa. The relations to other A(2)BX(6)-type structures are discussed. DICVOL 2005-43 Vila, E Iglesias, JE Galy, J Castro, A Synthesis and characterization of a novel bismuth-molybdenum oxide and study of its ionic conducting behavior SOLID STATE SCIENCES 7, 2005, 1369-1376. A wet chemistry method applied to the synthesis of bismuth-molybdenum oxides leads to the low temperature synthesis of a new phase with composition Bi10Mo3O24. The crystal data have been determined by ab initio indexing of the powder pattern. It crystallizes in the monoclinic system, with unit-cell parameters a = 23.7235(4), b = 5.64720(8), c = 8.6798(1) angstrom, beta = 95.879(1)degrees and V = 1156.73 angstrom(3). A preliminary heavy-atom skeleton related to the fluorite structure allowed us to postulate a layer structure with composition [Bi10O12](n) [MoO4](3n): This compound has been processed by spark plasma sintering as a ceramic material, exhibiting good ionic conductor properties in the whole temperature range of stability. DICVOL 2005-44 Blagden, N Davey, R Dent, G Song, M David, WIF Pulham, CR Shankland, K Woehler and Liebig revisited: A small molecule reveals its secrets - The crystal structure of the unstable polymorph of benzamide solved after 173 years CRYSTAL GROWTH & DESIGN 5, 2005, 2218-2224. In this work, we revisit the question of the metastable crystal form of benzamide. This was first identified in 1832 by Liebig and Woehler, but its structure has never been determined. It is shown how a combination of microscopic, spectroscopic, and diffraction techniques have been used to solve, finally, the structure of this highly metastable Form II of benzamide. The combination of morphology, disorder, and nucleation under highly labile conditions lead to some speculation as to the origins of such an unstable polymorph. DICVOL 2005-45 David, WIF Shankland, K Pulham, CR Blagden, N Davey, RJ Song, M Polymorphism in benzamide ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 44, 2005, 7032-7035. DICVOL 2005-46 Surble, S Serre, C Millange, F Pelle, F Ferey, G Synthesis, characterisation and properties of a new three-dimensional Yttrium-Europium coordination polymer SOLID STATE SCIENCES 7, 2005, 1074-1082. A new three-dimensional europium-doped Yttrium(III) tricarboxylate, MIL-92LT(1) or Y1-xEux (H2O)(2) {C6H3-(CO2)(3)} (x similar to 0.03) (LT: Low Temperature) has been synthesised hydrothermally. Its three-dimensional structure, determined using X-ray powder diffraction data, is built-up from isolated eight coordinated Ln(III) monocapped square antiprisms (Ln = Y, Eu) linked through carboxylate moieties. Its thermal behaviour, investigated using TGA and X-ray thermodiffractometry indicates that dehydration is irreversible giving the solid MIL-92(HT) or Y1-xEux {C6H3-(CO2)(3)} (x similar to 0.03) (HT: High Temperature). It induces a change in the connection mode of the carboxylate and a decrease in the coordination number of the rare-earth leading to an unusual octahedral environment for the rare-earth cation. After a structural analysis of the reconstructive phase transition, the optical properties of these solids have been investigated and show that dehydration leads to a strong increase in the optical output. Crystal data for MIL-92(LT): monoclinic space group C2/c (n degrees 15) with a = 16.428 (1) angstrom, b = 6.071 (1) angstrom, c = 20.404(l) angstrom, beta = 95.31(3)degrees and Z = 2. Crystal data for MIL-92(HT): monoclinic space group C2/c (n degrees 15) with a = 17.390(1) angstrom, b = 5.521 (1) angstrom, c = 19.487(1) angstrom, beta = 105.35 (2)degrees and Z = 2. DICVOL 2005-47 Harper, JK Barich, DH Heider, EM Grant, DM Franke, RR Johnson, JH Zhang, YG Lee, PL Von Dreele, RB Scott, B Williams, D Ansell, GB A combined solid-state NMR and X-ray powder diffraction study of a stable polymorph of paclitaxel CRYSTAL GROWTH & DESIGN 5, 2005, 1737-1742. Solid-state NMR (SSNMR) and X-ray powder diffraction (XRPD) allow a study of a novel and stable polymorph of paclitaxel (Taxol) with two molecules per asymmetric unit (Z') in the P2(1)2(1)2(1) space group. The asymmetric unit volume is 2167 angstrom(3), about four times larger than that previously characterized in combined XRPD/ SSNMR studies. The method, employing SSNMR constraints, allows the XRPD Rietveld analysis to establish many of the lattice details that otherwise would be unavailable. NMR structural constraints are provided by isotropic shifts and three-dimensional (3D) chemical shift tensors (CST), which are determined by ab initio quantum mechanical calculations. CST data give highly sensitive information on short-range structural features such as intra-atomic distances (particularly for proton positions that are undetermined with XRPD methods) and short-range valence angles that exhibit relatively poor sensitivity in reasonably large microcrystalline powders. Conversely, space group symmetry, unit cell volumes, long-range cell dimensions, and dihedral angles of extended chains are estimated with XRPD measurements. Corroboration of many structural parameters by combined quantum mechanical, SSNMR, and XRPD results indicate the efficacy of these combined approaches in relatively sizable microcrystalline powders. The population of the asymmetric unit, Z' = 2 is clearly observed even in the one-dimensional isotropic C-13 spectra, which also confirmed the stability of the polymorph over a three-year period. This structural determination depends specifically on the agreement between previous SSNMR CSTs and single crystal results for baccatin, the rigid part of paclitaxel. Hence, CST data provide a reasonable initial model for the early iterative steps of a Rietveld analysis of XRPD data for a new polymorph of Taxol. DICVOL 2005-48 Wu, L Chen, XL Li, H He, M Xu, YP Li, XZ Structure determination and relative properties of novel cubic borates MM '(4)(BO3)(3) (M = Li, M ' = Sr; M = Na, M ' = Sr, Ba) INORGANIC CHEMISTRY 44, 2005, 6409-6414. A series of novel borates, MM'(4)(BO3)(3) (M = Li, M' = Sr; M = Na, M' = Sir, Ba), have been successfully synthesized by standard solid-state reaction. The crystal structures have been determined from powder X-ray diffraction data. They crystallize in the cubic space group laid with large lattice parameters: a = 14.95066(5) angstrom for LiSr4(BO3)(3), a = 15.14629(6) angstrom for NaSr4(BO3)(3), and a = 15.80719(8) angstrom for NaBa4(BO3)(3). The structure was built up from 64 small cubic grids, in which the M' atoms took up the corner angle and the BO3 triangles or MO6 cubic octahedra filled in the interspaces. The isolated [BO3](3-) anionic groups are perpendicular to each other, distributed along three (100) directions. The anisotropic polarizations were counteracting, forming an isotropic crystal. Sr and Ba atoms were found to be completely soluble in the solid solution NaSr4-xBax(BO3)(3)(0 <= x <= 4). The photoluminescence of samples doped with the ions Eu2+ and Eu3+ was studied, and effective yellow and red emission was detected, respectively, The results are consistent with the crystallographic study. The! DTA and TGA curves of them show that they are chemically stable and congruent melting compounds. DICVOL 2005-49 Florence, A Johnston, A Fernandes, P Shankland, K Stevens, HNE Osmundsen, S Mullen, AB Powder study of hydrochlorothiazide form II ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 61, 2005, O2798-O2800. The crystal structure of hydrochlorothiazide form II, C7H8ClN3O4S2, was solved by simulated annealing from laboratory X-ray powder diffraction data collected at room temperature to 1.76 angstrom resolution. Subsequent Rietveld refinement yielded an R-wp of 0.0376 to 1.49 angstrom resolution. The molecules crystallize in the space group P2(1)/c with one molecule in the asymmetric unit. The structure is stabilized by three N-H (. . .) N and one N-H (. . .) O hydrogen-bonded intermolecular interaction. DICVOL 2005-50 Florence, AJ Johnston, A Shankland, K Powder study of hydrochlorothiazide-methyl acetate (1/1) ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 61, 2005, O2974-O2977. A polycrystalline sample of the title compound, C(7)H(8)ClN(3)O(4)S(2) . C3H6O2, was produced during an automated parallel crystallization search on hydrochlorothiazide (HCT). The crystal structure was solved by simulated annealing from laboratory X-ray powder diffraction data collected at room temperature to 1.75 angstrom resolution. Subsequent Rietveld refinement yielded an R-wp value of 0.0182 to 1.54 angstrom resolution. The compound crystallizes with one molecule of HCT and one of methyl acetate in the asymmetric unit and displays an extensive hydrogen-bonding network. DICVOL 2005-51 Banerjee, S Mukherjee, AK Banerjee, I De, RL Neumann, MA Louer, D Synthesis, spectroscopic studies and ab-initio structure determination from X-ray powder diffraction of bis-(N-3-acetophenylsalicylaidiminato)copper(II) CRYSTAL RESEARCH AND TECHNOLOGY 40, 2005, 815-821. The synthesis, spectroscopic studies and crystal structure determination from X-ray powder diffraction have been carried out for bis-(N-3-acetophenylsalicylaldiminato)copper(II). The structure is triclinic, space group P (l) over bar with unit cell dimensions a=11.817(1)angstrom, b=12.087(1)angstrom, c=9.210(1)A, alpha=102.62(1)degrees, beta=111.16(1)degrees, gamma=86.15(1)degrees, V=1197.0(2)angstrom(3), Z=2. The structure has been solved by Monte Carlo simulated annealing approach and refined by GSAS package. The final Rp value was 8.68%. The coordination geometry around the copper atom in the complex is intermediate between square-planar and tetrahedral with two salicylaldimine ligands in trans arrangement. Intermolecular C-(HO)-O-.... hydrogen bonds between molecules related by translation generate infinite chains along [010] direction. The molecular chains are linked via additional C-(HO)-O-.... hydrogen bonds to form a three-dimensional supramolecular network. DICVOL 2005-52 Zhang, LM Schneider, J Luck, R Phase transformations and phase stability of the AlCuFe alloys with low-Fe content INTERMETALLICS 13, 2005, 1195-1206. Phase transformation and microstructure of the AlCuFe alloys of the approximate compositional range of 20-50 at.% Cu and 1-10 Fe at.% have been investigated for annealed samples by means of differential thermal analysis, magneto-thermal analysis, scanning electron microscopy, electron probe analysis and powder X-ray diffraction. Representative phase transformations categorized as polymorphic, discontinuous precipitation, quasi-binary eutectoid, and ternary transition reaction (U-type) phase transformation are presented. These phase transformations are found to have a common feature, which is characterized by a dissolution of a primitive CsCl-type cubic phase and a formation of a face-centered orthorhombic phase. The crystal structures of the cubic and orthorhombic phases are determined from the powder diffraction data using routines for indexing DICVOL, for intensity extraction and ab initio structure determination EXPO and for Rietveld refinement FULPROF. A face-centered orthorhombic cell (a = 8.1530(3), b = 14.1370(4), c = 10.0736(4), Vol = 1161.0(7), Z = 4, at room temperature) with a starting structural model of,zeta-Al3Cu4 (space group Fmm2, Z=4) approximates the observed pattern of powder sample quenched from 620 degrees C fairly well. Refined orthorhombic cell dimensions are obtained by in situ high-temperature X-ray diffraction at 463, 553 and 636 degrees C. These phase transformations are sensitive to the heat treatment and the alloy composition. They can be suppressed at moderate cooling rates. The metastable structures for both slowly cooled and as-cast alloys are found to contain the cubic phase replacing the equilibrium orthorhombic phase. DICVOL, EXPO, FULLPROF 2005-53 Littner, A Francois, M Tobola, J Elkaim, E Malaman, B Vilasi, M Ab-initio crystal structure of Mo4+xRu9-xSi5 (0 <= x <= 1) by synchrotron powder diffraction and electronic properties calculation (KKR method) INTERMETALLICS 13, 2005, 1048-1055 The crystal structure of the new phase Mo26Ru47Si27 (beta phase) discovered during the study of the Mo-Ru-Si phase diagram performed in the aim of finding materials for high temperature applications, was determined by ab-initio methods from powder synchrotron diffraction data. Distribution of Ru and Mo atoms in the structure is specified by total energy electronic structure calculations using Korringa-Kohn-Rostoker method. The compound crystallizes in P4/mmm space group with a=9.2164(1) angstrom, c=2.88721(1), angstrom, D-x = 9.69(1) g/cm(3). The structure has been refined by the Rietveld method down to R-p = 1.1%, R-B = 12.0%, R-F = 8.7% for 6814 observed data and 271 independent reflections. The structure consists of four distorted cubes 'Mo4Si4' centered by Ru atoms, sharing edges in the (a,b) planes to form cross-like units linked each others by the lateral faces of the branches in the (a,b) planes and stacked by faces along the c direction. The center of the crosses is occupied by Mo or Ru atoms (disorder 1d site) in an octahedral coordination. The spacing between the connected crosses is filled by four others distorted cubic units 'Mo4Si4' centered themselves by Ru atoms. The composition of the beta phase, determined by microprobe analysis, presents an homogeneity domain, which can be expressed by the unit formula Mo4+xRu9-xSi5 (0 <= x <= 1) compatible with a partial or fully occupation by Mo or Ru of the Wyckoff position Id of the structure. Electronic properties of ordered and disordered models of Mo4+xRu9-xSi5 are also discussed. DICVOL 2005-54 ?? Rousse, G Klotz, S Saitta, AM Rodriguez-Carvajal, J McMahon, MI Couzinet, B Mezouar, M Structure of the intermediate phase of PbTe at high pressure PHYSICAL REVIEW B 71, 2005, 224116 The evolution of PbTe with pressure has been reexamined using synchrotron x-ray diffraction. The phase transition at 6 GPa is not to the GeS (B16) or TII (B33) type structures, as previously reported, but to an orthorhombic Pnma structure, with cell parameters a=8.157(1), b=4.492(1), and c=6.294(1)A at 6.7 GPa. This structure corresponds to a distortion of the low-pressure NaCl structure with a coordination intermediate between the sixfold B1 (NaCl) and the eightfold B2 (CsCl) structure. We discuss the stability of this new structure with respect to other proposed phases using numerical methods. These results may modify the admitted paths of phase transitions between the B1 and B2 structures. DICVOL 2005-55 Loiseau, T Muguerra, H Haouas, M Taulelle, F Ferey, G Hydrothermal synthesis and structural characterization of a gallium pyromellitate Ga(OH)(btec) . 0.5H(2)O, with infinite Ga-(mu(2)-OH)Ga chains (MIL-61) SOLID STATE SCIENCES 7, 2005, 603-609 A new gallium carboxylate Ga(OH)(btec) . 0.5H(2)O (MIL-61) was synthesized under mild hydrothermal conditions (200 degrees C, 24 hours) in the presence of 1,2,4,5-benzenetetracarboxylic (btec) acid and water. The crystal structure, characterized by means of Rietveld refinement of powder XRD data, consists of trans chains of GaO4(OH)(2) octahedra, connected to each other through a mu(2)-OH group. The three-dimensional framework is built up from these chains linked together via the organic molecules so delimiting the cavities where the water molecules are encapsulated. Analysis by solid state NMR (1 H and C-13) has confirmed the presence within the structure of both water molecules and carboxylate moieties partially deprotonated. The structure of Ga(OH)(btec) . 0.5H(2)O corresponds to that of MIL-61 obtained with vanadium replacing gallium. Crystal data for Ga-4(OH)(4)((HO2C)(2)-C6H4-(CO2)(2))(4) . 2H(2)O: a = 14.8325(10) angstrom, b = 6.7792(10) angstrom, c = 10.6726(10) angstrom, V 1073.2(2) angstrom(3), Prima (n degrees 62). DICVOL 2005-56 van der Lee, A Richez, P Tapiero, C Crystal structure of nitarsone determined from synchrotron X-ray powder diffraction data JOURNAL OF MOLECULAR STRUCTURE 743, 2005, 223-228. The crystal structure of nitarsone, 4-nitrophenylarsonic acid, a substitute for nifursol and dimetridazole in the prevention and treatment of turkey histomoniasis desease, has been determined from synchrotron X-ray powder diffraction data. Nitarsone crystallizes in the monoclinic space group P2(1)/n with unit cell parameters a = 7.46413(5), b = 25.68543(17), c = 4.657388(32) &ANGS;, β = 105.4670(5)&DEG;. The structure was solved using simulated annealing techniques by treating the molecule as a rigid body for which the configuration resulting from an energy minimization was used in slightly adapted form, Structure refinement treated the NO2 and the AsO(OH)(2) groups as free groups, leading to final confidence factors R-p = 0.059 and R-wp = 0.071. The crystal structure contains 4 molecules per unit cell that are hydrogen bonded to form infinite chains of dimers running along the c-axis. Nitarsone's low toxicity when compared with inorganic sources of arsenic is explained by the existence of a partial double C-As bond (1.866(5) &ANGS;) which confers greater stability so that under physiological conditions nitarsone is not converted to mineral-like As V or III. DICVOL 2005-57 Guo, F Harris, KDM Structural understanding of a molecular material that is accessed only by a solid-state desolvation process: The scope of modern powder X-ray diffraction techniques JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127, 2005, 7314-7315. HEMIMELLITIC ACID DIHYDRATE; GENETIC ALGORITHM DICVOL 2005-58 Papoular, RJ Allouchi, H Chagnes, A Dzyabchenko, A Carre, B Lemordant, D Agafonov, V X-ray powder diffraction structure determination of gamma-butyrolactone at 180 K: phase-problem solution from the lattice energy minimization with two independent molecules ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 312-320. The crystal structure of the solid phase of the dipolar aprotic solvent γ-butyrolactone (BL1), C4H6O2, has been solved using the atom-atom potential method and Rietveld-refined against powder diffraction data collected at T = 180 K with a curved position-sensitive detector (INEL CPS120) using Debye-Scherrer diffraction geometry with monochromatic X-rays. It was first deduced from the X-ray experiment that the lattice parameters are a = 10.1282 (4), b = 10.2303 (5), c = 8.3133 (4) &ANGS;, β = 93.291 (2)&DEG; and that the space group is P2(1)/a, with Z = 8 and two independent molecules in the asymmetric unit. The structure was then solved by global energy minimization of the crystal-lattice atom-atom potentials. The subsequent GSAS-based Rietveld refinement converged to the final crystal-structure model indicator R-F2 = 0.0684, profile factors R-p = 0.0517 and R-wp = 0.0694, and a reduced χ(2) = 1.671. After further cycles of heating and cooling, a powder diffraction pattern markedly different from the first pattern was obtained, again at T = 180 K, which we tentatively assign to a second polymorph (BL2). All the observed diffraction peaks are well indexed by a triclinic unit cell essentially featuring a doubling of the a axis. An excellent Le Bail fit is obtained, for which R-p = 0.0312 and R-wp = 0.0511. DICVOL 2005-59 Loiseau, T Mellot-Draznieks, C Muguerra, H Ferey, G Haouas, M Taulelle, F Hydrothermal synthesis and crystal structure of a new three-dimensional aluminum-organic framework MIL-69 with 2,6-naphthalenedicarboxylate (ndc), Al(OH)(ndc) . H2O COMPTES RENDUS CHIMIE 8, 2005, 765-772. A new three-dimensional aluminum-organic framework, MIL-69 or Al(OH)(O2C-C10H6-CO2)(H2O)-H-., has been hydrothermally synthesized at 210 &DEG; C for 16 h, by using 2,6-naphthalenedicarboxylic acid as a rigid ligand. The model for the crystal structure of MIL-69 was determined by means of lattice energy minimizations and further refined against the powder XRD data using the Rietveld refinement method. The crystal structure consists of infinite chains of AlO4(OH)(2) octahedra corner-linked through the μ(2)-hydroxyl groups and connected by the 2,6-naphthalenedicarboxylate moieties. It results in the formation of flat channels parallel to the chains of aluminum octahedra, running along the c axis. A water molecule is trapped nearby the center of the tunnels and mainly interacts via hydrogen bonds with the hydroxyl groups and the oxygen atoms of the carboxylates. Although the three-dimensional aluminum-organic framework is stable up to 450 &DEG; C, the tunnels still remain shrunk upon removal of water molecule, because of the occurrence 7r-n interactions between the naphthalene groups. The MIL-69 phase was characterized by solid state NMR MAS(27)Al, H-1 and C-13{H-1-decoupled}, which is consistent with the crystal structure description. Crystal data. - MIL-69, Al(OH)(O2C-C10H6-CO2)(H2O)-H-.: Mr = 267.11 g mol(-1), monoclinic, space group C2/c (no. 15), a = 24.598(2) &ANGS;, b = 7.5305(6) &ANGS;, c = 6.5472(5) &ANGS;, β = 106.863(8)&DEG;, V = 1160.6(2) &ANGS;(3), Z = 4. DICVOL 2005-60 Fernandes, P Florence, A Shankland, K David, WIF Powder diffraction study of 1,2 : 3,4-dibenzanthracene ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 61, 2005,O1483-O1485. The crystal structure of 1,2:3,4-dibenzanthracene, C22H14, was solved by simulated annealing from laboratory X-ray powder diffraction data collected at room temperature to 1.8 &ANGS; resolution. Subsequent Rietveld refinement yielded an R-wp value of 0.036. The molecules crystallize in space group P2(1) with two independent molecules in the asymmetric unit which pack in a stacked arrangement along the b axis. DICVOL 2005-61 Lewis, GR Steele, G McBride, L Florence, AJ Kennedy, AR Shankland, N David, WIF Shankland, K Teat, SJ Hydrophobic vs. hydrophilic: Ionic competition in remacemide salt structures CRYSTAL GROWTH & DESIGN 5, 2005, 427-438. Remacemide [2-aniino-N-(1-methyl-1,2-diphenylethyl)-acetamide] was developed as a potential antagonist for epilepsy, Parkinsonism, and Huntington's disease. This paper investigates hydrophilic and hydrophobic intermolecular interactions that occur within the series of crystal structures comprising remacemide 1 and six of its salts [2 = chloride; 3 = nitrate; 4 = acetate (C2H3O2-); 5 = hydrogenfumarate (C4H3O4-); 6 = naphthalene-2-sulfonate (napsilate, C10H7O3S-); 7 = 1-hydroxynaphthalene-2-carboxylate (xinafoate, C11H7O3-)]. The hydrophilic interactions are described through graph set analyses of the hydrogen bond motifs and networks. The lattice of 1 comprises unidirectional, one-dimensional chains of molecules parallel to the c-axis. In 2, the cation-anion hydrogen bonding imposes a well-defined hydrophilic stratum structure on the lattice. As the cation itself is amphiphilic, a natural consequence of this is the creation of two-dimensional stacked layers with alternating hydrophilic and hydrophobic character (lattice bilayers). This tendency to form bilayers within the lattice is also observed in structures 3-5 (polar anions) and structures 6-7 (amphiphilic anions). Relatively few well-directed intermolecular interactions are observed between aromatic rings, either in 1 or in the hydrophobic layers of 2-7. Therefore, it is concluded that it is the hydrophilic hydrogen bond interactions that dominate the crystal packing and drive the segregation into lattice bilayers in the salt crystal structures. DICVOL 2005-62 Bhuvanesh, NSP Reibenspies, JH Golden, ML Darensbourg, MY Zhang, YG Lee, PL The vapochromic behavior, desulfoxidation and structural characterization of the SO2 adducts of Ni(BME-DACH) from powder data SYNTHESIS AND REACTIVITY IN INORGANIC METAL-ORGANIC AND NANO-METAL CHEMISTRY 35, 2005, 11-17. Ab-initio structure determination of Ni(BME-DACH). SO2 has been carried out by a combination of real space methods and Rietveld analysis from powder X-ray diffraction patterns obtained from microgram quantities of the compound mounted on a nylon loop (space group. P2(1)/c, a = 8.871(1), b = 14.480(1), c = 10.576(1) angstrom, beta = 95.98(1)degrees. The structure of Ni(BME-DACH). SO2 shows that Ni(BME-DACH) complex remains intact and is related to the structure of Ni(BME-DACH).2SO(2), providing a platform for SO2 binding. We have also followed the desulfoxidation of the 2SO(2) adduct by in-situ micro-powder X-ray diffraction and, based on the results, a mechanism is proposed. DICVOL 2005-63 Janaswamy, S Chandrasekaran, R Polysaccharide structures from powder diffraction data: molecular models of arabinan CARBOHYDRATE RESEARCH 340, 2005, 835-839. X-ray intensity data from a polycrystalline sample of debranched arabinan, [-> 5)-alpha-L-Ara(f)-(1 ->](n), have been obtained using a powder diffractometer in order to determine its three-dimensional structure. The observed peaks index on a monoclinic cell with a = 5.444(7), b = 6.395(10), c = 8.680(5) angstrom, and gamma = 99.6(3)degrees, V = 298 angstrom(3). One 2-fold helix along the c-axis can be accommodated in the unit cell. Molecular and packing models have been analyzed using the seven C-2'-endo/C-3'-endo allomorphs originally proposed by Radha and Chandrasekaran [Carbohydr. Res. 1997, 298, 105]. The generated powder pattern matches closely with the observed diffraction only for one C-2'-endo model. In this structure, the three main chain conformation angles are in the trans domains, there are no intra-chain hydrogen bonds, and the packing arrangement is stabilized by inter-chain O-3-(HO)-O-...-2 bonds. DICVOL 2005-64 Yuan, WX Hu, JW Song, YT Wang, WJ Xu, YP Synthesis and structure of the ternary nitride Li6WN4 POWDER DIFFRACTION 20, 2005, 18-21. The ternary nitridotungstate Li6WN4 has been synthesized via the solid state reaction of lithium subnitride, Li3N, with W under nitrogen. High quality X-ray powder diffraction data were collected for the crystal-structure determination. Li6WN4 crystallizes in the tetragonal system, space group P4(2)/nmc, with cell parameters a = 6.6759(3) angstrom and c = 4.9280(3) angstrom, Z = 2. Preliminary thermal stability measurements of Li6WN4 show that it is sensitive to moisture, even at room temperature, and decomposes at high temperatures below 1000 degrees C under flowing nitrogen. DICVOL 2005-65 Hofmann, K Albert, B Crystal structures of M-2[B10H10] (M = Na, K, Rb) via real-space simulated annealing powder techniques ZEITSCHRIFT FUR KRISTALLOGRAPHIE 220, 2005, 142-146. Alkali metal decahydro-closo-decaborates M-2[B10H10] (M = Na, K, Rb) were synthesised by ion-exchange and characterised via infrared and B-11-NMR spectroscopy. The crystal structures of Na-2[B10H10,], K-2[B10H10], and Rb-2[B10H10] were determined from X-ray powder diffraction data using real-space techniques. The compounds crystallise in the monoclinic space group P2(1)/n (no. 14) with the lattice constants: Na2[B10H10]: a = 1028.28(6) pm, b = 1302.18(5) pm, c = 667.34(3) pm, beta = 93.754(3)degrees; K-2[B10H10]: a = 1285.54(8) pm, b = 1117.84(7) pm, c = 682.27(4) pm, beta = 93.357(3)degrees; Rb-2[B10H10]: a = 1320.04(7) pm, b = 1136.88(6) pm, c = 704.23(4) pm, P = 94.158(3)degrees. The hydroborate anions are arranged almost hexagonally with alkali metal cations in the tetrahedral interstices. DICVOL 2005-66 Chui, SSY Ng, MFY Che, CM Structure determination of homoleptic Au-I, Ag-I, and Cu-I aryl/alkylethynyl coordination polymers by X-ray powder diffraction CHEMISTRY-A EUROPEAN JOURNAL 11, 2005, 1739-1749. This article describes the structure determination of five homoleptic d(10) metal-aryl/alkylacetylides [RC equivalent to CM] (M=Cu, R=tBu 1, nPr 2, Ph 3; R = Ph, M = Ag 4; Au 5) by using X-ray single-crystal and powder diffraction. Complex 1(.)C(6)H(6) reveals an unusual Cu-20 catenane cluster structure that has various types of tBuC equivalent to C -> Cu coordination modes. By using this single-crystal structure as a starting model for subsequent Rietveld refinement of X-ray powder diffraction data, the structure of the powder synthesized from CuI and tBuC equivalent to CH was found to have the same structure as 1. Complex 2 has an extended sheet structure consisting of discrete zig-zag Cu-4 subunits connected through bridging nPrC equivalent to C groups. Complex 3 forms an infinite chain structure with extended Cu-Cu ladders (Cu-Cu = 2.49(4)-2.83 (2) angstrom). The silver(I) congener 4 is iso-structural to 3 (average Ag-Ag distance 3.11 angstrom), whereas the gold(I) analogue 5 forms a (AuAu)-Au-... honeycomb network with PhC equivalent to C pillars (Au-Au = 2.98(1)-3.26(1) angstrom). Solid-state properties including photoluminescence, v(C equivalent to C) stretching frequencies and thermal stability of these polymeric systems are discussed in the context of the determined structures. 2005-67 Stock, N Guillou, N Senker, J Ferey, G Bein, T Synthesis and characterization of the tetraphosphonic acid ester (Et2O3PCH2)(4)C6H2 and the open-framework cadmium tetraphosphonate, Cd-2[(HO3PCH2)(4)C6H2] ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 575-581. Following the strategy of using polyfunctional phosphonic acids for the synthesis of open-framework metal phosphonates, the ethyl ester of a tetraphosphonic acid, i. e. (Et2O3PCH2)(4)C6H2 (1) was synthesized and used in the hydrothermal synthesis of the new cadmium tetraphosphonate, Cd-2[(HO3PCH2)(4)C6H2] (2). The structure of 1 was solved from single crystal data (1: triclinic, P (1) over bar, a 12.3846(2), b = 12.6166(3), c 12.9915(3) Angstrom, alpha = 86.380(1), beta = 63.372(1), gamma = 89.589(1)degrees, V = 1810.51(7) Angstrom3, Z = 2, R1 = 0.077, wR2 = 0.177). The in situ hydrolysis of the ethyl ester and the reaction with the Cd2+ ions leads to the well-crystallized microcrystalline product 2. Its structure was solved and refined using X-ray powder diffraction data (2: triclinic, P (1) over bar, with a = 11.0435(5), b = 7.5809(3), c = 5.4250(2) Angstrom, alpha = 98.354(2), beta = 101.951(2), gamma = 95.885(3)degrees, V = 435.48(9) Angstrom3, Z = 1, R(w)p = 0.096, R-P = 0.072, R-B = 0.081, R-F = 0.069). Whereas the structure of I is a molecular structure, the structure of Cd-2[(HO3PCH2)(4)C6H2] (2) is built up from edge sharing CdO6 octahedra forming dimeric [Cd2O10] polyhedra. In the second coordination sphere of each of the Cd-II ions six HO3PCH2R units are observed. The [Cd2O10] polyhedra are connected to six other [Cd2O10] polyhedra by ten hydrogenphosphonic acid units. Thus inorganic sheets are formed that are connected to a three-dimensional framework with small channels, through the phenyl rings. Thermogravimetric as well as IR-, Cd-13-MAS-NMR and P-31-MAS-NMR data are also presented. DICVOL 2005-68 Abdelouhab, S Francois, M Elkaim, E Rabu, P Ab initio crystal structure of copper(II) hydroxy-terephthalate by synchrotron powder diffraction and magnetic properties SOLID STATE SCIENCES 7, 2005, 227-232. The structure of Cu-2(OH)(2)(C8H4O4) has been determined by ab initio XRPD methods from synchrotron data. The compound crystallizes in P-1 space group, a = 10.1423(4) Angstrom, b = 6.3388(2) Angstrom, alpha = 3.4841(1) Angstrom, alpha = 99.170(2)degrees, beta = 96.567(2)degrees, gamma = 98.760(3)degrees, D-x = 2.497 g cm(-3). The structure has been fully refined by the Rietveld method down to R-p = 0.077 for 9651 observed data points (513 reflections of which 193 are independent). The structure consists of layered hydroxides Cu(OH)(2) intercalated by terephthalate anions, at the interlayer space forming a 3D framework similar to Co(II)-based compound. The apticity of the tp anion and the octahedral coordination of the metal ions are similar in both compounds and can be formulated as M-2(mu(3)-OH)(2)(A(6)-eta(1), eta(2), eta(1), eta(2)-tp) with M = Cu and Co. Although Cu(II)-based structure is very similar to the monoclinic (C2/m) Co(II)-based analogue, the former is completely ordered in contrast with the later which is disordered. The lower symmetry in Cu(II)-based compound due to the Jahn-Teller effects inducing an elongation of the octahedrons CuO6 with four short distances of about 2.0 Angstrom and two long distances Cu-O up to 2.8 Angstrom is also observed to be different from Co(II)-based compound. Whereas the Co(II) derivative exhibits noncollinear antiferromagnetic coupling between the ferrimagnetic hydroxide layers, the magnetic behavior of the copper(II) analogue indicate a ferromagnetic coupling through the terephthalate bridge between ferromagnetic sheets with in-plane interaction J = +5.5 K. DICVOL 2005-69 Vanhoyland, G Pagnaer, J D'Haen, J Mullens, S Mullens, J Characterization and structural study of lanthanum citrate trihydrate [La(C6H5O7)(H2O)(2)] . H2O JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 166-171. [La(C6H5O7)(H2O)(2)] (.) H2O was synthesized as precursor material for an aqueous solution-get route to La-containing multimetal oxides. The compound was characterized by means of FTIR, TGA and pycnometry. The crystallographic structure was solved from powder diffraction data. The symmetry is monoclinic [a = 17.097(3) Angstrom, b = 9.765(2) Angstrom, c = 6.3166(8) Angstrom and beta = 90.42(1)degrees, Z(exp) = 3.96] with space group P2(1)/n (14). Direct methods were applied and the model was subsequently least-squares refined (R-B 5.1 % and R-wP = 12.0%). La3+ is nine-fold coordinated, the LaO9 forming a mono-capped square antiprism. The basic unit is a binuclear entity of two LaO9 polyhedra having one edge in common. These units are connected along the c-axis through citrate molecules. The carboxylate groups of the citrate are coordinated to La3+ in monodentate, bidentate and bridging way. Also the alkoxide group, which carries the proton, is coordinated to La3+. Two water molecules complete the coordination sphere, while the third one can be found inbetween the La3+ -citrate network. DICVOL 2005-70 Josse, M Dubois, M El-Ghozzi, M Cellier, J Avignant, D Anti-KSbF6 structure of CaTbF6 and CdTbF6: a confirmation of the singular crystal chemistry of Tb4+ in flourides ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 1-10. The crystal structures of two new tetravalent terbium fluorides, CaTbF6 (and CdTbF)(, have been determined from X-ray and neutron powder diffraction data. The title compounds exhibit an anti-KSbF)(6)(6) (structure, the three-dimensional framework of which is built of [TbF)(]2- chains of edge-sharing dodecahedra further linked, by sharing corners, to isolated [MF)(]4- octahedra (M = Ca, Cd). The mechanism of the anionic sublattice rearrangement when going from KSbF)(6)(6)(6) (to CaTbF)(6) (is described and related to a simple cubic fluoride-ion packing. Comparison with the crystal structures of b-BaTbF)(6) (and other representatives of the MII MIVF)(6) family allows the singular crystal-chemical properties of some fluoroterbates to be emphasized. DICVOL 2005-71 Mora, AJ Avila, EE Delgado, GE Fitch, AN Brunelli, M Temperature effects on the hydrogen-bond patterns in 4-piperidinecarboxylic acid ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 96-102. A temperature-controlled X-ray powder diffraction experiment, complemented with TGA and DSC analysis, allowed us to follow changes in the molecular conformation and hydrogen-bond patterns of 4-piperidinecarboxylic acid. The presence of three phases is confirmed. Phase 1 represents the monohydrated form of 4-piperidinecarboxylic acid, which exists from room temperature to 359 K, where dehydration occurs. Phase 2 measured at 363 K corresponds to an anhydrous form of the acid. At ca 458 K the onset of a second, more gradual transition is observed, which ends at around 543 K. Phase 3 measured at 543 K is a high-temperature anhydrous form of the acid. The structures of phases 2 and 3 were solved from synchrotron powder diffraction data by simulated annealing using the DASH program and refined by the Rietveld method. The phase changes are accompanied by modification of the hydrogen-bond patterns and of the torsional orientation of the terminal carboxylate group. This group makes a 49degrees rotation about the C1 - C2 bond during the first transition. DICVOL 2005-72 Casellas, H Costantino, F Mandonnet, A Caneschi, A Gatteschi, D X-ray powder and single crystal structures of two unprecedented families of bpca-based 1-D magnetic chains (Hbpca = bis(2-pyridylcarbonyl)amine) INORGANICA CHIMICA ACTA 358, 2005, 177-185. Two unprecedented families of bpca-based mono-dimensional complexes Cu(bpca)(X) (X = CN, 1; N-3, 2) and [Cu1-xFex(bpca)](ClO4) (X = 0, 3; 0.23, 4) were synthesised. The structure of I was solved ab initio from X-ray powder diffraction data and refined by Rietveld methods. The complexes 3-4 were characterised by X-ray single crystal diffraction. In I the cyano ligand coordinates the metal centres, the Cu centres forming a zigzag 1-D chain along the (0 0 1) direction, while in 3-4, the bpca ligand itself acts as the link towards the metal ions which are arranged in a linear 1-D chain running parallel to the (0 0 1) direction. An infrared spectroscopy study confirmed these coordination modes. The magnetic properties of both chain families were studied. 1-2 do not show significant magnetic interactions, whereas the magnetic behaviour for 3-4 suggests dominant antiferromagnetic interactions between the metal ions within the chains. The magnetic behaviour of 3 was analysed using the Pade approximation of the Bonner-Fisher model for S = 1/2 antiferromagnetic chains. The J value was estimated as 10 K. DICVOL 2005-73 ??? Pitt, MP Blanchard, D Hauback, BC Fjellvag, H Marshall, WG Pressure-induced phase transitions of the LiAlD4 system PHYSICAL REVIEW B 72, 2005, 214113 Compression of the LiAlD4 system has been studied using in situ time-of-flight neutron diffraction up to 7.15 GPa and 60 degrees C. At ambient temperature (T-a), the structure remains as monoclinic alpha-LiAlD4 up to 7.05 GPa, displaying a 26.9% reduction in unit cell volume to 200.9 angstrom(3), yielding a 28.7% increase in volumetric efficiency to 136.5 kg D-2/m(3). Decompression to a small 3 ton load at T-a and holding for 24 hours did not induce any phase transformation, and the starting 0 GPa alpha-LiAlD4 structure was eventually recovered. Heating from T-a to 60 degrees C while under compression to 7.15 GPa produces new and intense reflections in the diffraction pattern, while also retaining alpha-LiAlD4 reflections, indicating a two-phase alpha/beta-LiAlD4 mixture. The beta-LiAlD4 structure indexed from this data is in the monoclinic space group I2/b, with unit cell dimensions a=4.099(3) angstrom, b=4.321(4) angstrom, c=10.006(7) angstrom, gamma=88.43(2)degrees, yielding a volumetric efficiency of 151.2 kg D-2/m(3). The atomic arrangement in I2/b is identical to that in the theoretically predicted I4(1)/a super group, with isolated symmetric AlD4 tetrahedra displaying Al - D distances of 1.545(2) angstrom. Once again, decompression and cooling recovers the ambient alpha-LiAlD4 structure. 2005-74 Svoboda, J Zima, V Benes, L Melanova, K Vicek, M Synthesis and characterization of new calcium phenylphosphonates and 4-carboxyphenylphosphonates INORGANIC CHEMISTRY 44, 2005, 9968-9978. Three new calcium phenylphosphonates, CaC6H5PO3-2H(2)O, Ca-3(C6H5PO3H)(2)(C6H5PO3)(2)(.)4H(2)O, and CaC6H5PO3. H2O, and two calcium 4-carboxyphenylphosphonates, Ca(HOOCC6H4PO3H)2 and Ca-3(OOCC6H4PO3)(2)(.)6H(2)O, were prepared. It was found that CaC6H5PO3-2H2O transformed into previously known Ca(C6H5PO3H)(2) via Ca-3(C6H5PO3H)(2)(C(6)H5PO(3))(2)(.)4H(2)O in the presence of phenylphosphonic acid, and vice versa, Ca(C6H5PO3H)(2) turned into CaC(6)H(5)PO(3)(.)2H(2)O in a weak basic medium. A similar relationship was found between Ca(HOOCC6H4PO3H)(2) and Ca-3(OOCC6H4PO3)(2)(.)6H(2)O; i.e., Ca-3(OOCC6H4PO3)2(.)6H(2)O transformed into Ca(HOOCC6H4PO3H)(2) in the presence of 4-carboxyphenylphosphonic acid. On the contrary, Ca-3(OOCC6H4PO3)2(.)6H(2)O is formed from Ca(HOOCC6H4PO3H)(2) in the presence of ammonium as a weak base. The structure of Ca(HOOCC6H4PO3H)(2) was solved from X-ray powder diffraction data by an ab initio method using a FOX program. The compound is monoclinic, space group C21c (No, 15), a = 49,218(3) angstrom, b = 7.7609(4) angstrom, c = 5.4452(3) angstrom, beta = 128.119(3)degrees, and Z = 4. Its structure is one-dimensional with [Ca-2(HOOCC6H4PO3H)(4)](infinity) ribbons forming basic building blocks. The ribbons are held together by hydrogen bonds between carboxylic groups. 2005-75 ??? Barrier, N Pelloquin, D Nguyen, N Giot, M Bouree, F Raveau, B Ferrite Sr3NdFe3O9: An original intergrowth between the brownmillerite and K2NiF4-type structures CHEMISTRY OF MATERIALS 17, 2005, 6619-6623. The coupled neutron diffraction and Mossbauer study of the layered oxide Sr3NdFe3O9 shows for the first time the possibility of anionic vacancies ordering in an oxygen-deficient related Ruddlesden-Popper(RP-) type ferrite leading to an original intergrowth of brownmillerite and K2NiF4-type layers. The antiferromagnetic properties of this phase up to 500 K are also evidenced. These results open the route to the synthesis of new members in the series (Sr2Fe2O5)(n)center dot SrLnFeO(4) and to the understanding of their reactivity with atmospheric water. 2005-76 Karau, F Schnick, W Preparation and crystal structure of diammin magnesium diazide Mg(NH3)(2)(N-3)(2) ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 632, 2005, 49-53. Diammin magnesium diazide was synthesized from Mg3N2 and NH4N3 in liquid ammonia and crystallized at 150 degrees C under autogenous atmosphere of HN3 and NH3 using sealed ampoules. Mg(NH3)(2)(N-3)(2) is a colorless, microcrystalline powder which can detonate above 180 degrees C. Caution, preparation and manipulation of Mg(NH3)(2)(N-2)(2) is very dangerous! The crystal structure was solved from powder data using the Patterson method and a Rietveld refinement was performed (Mg(NH3)(2)(N-3)(2), I 4/m, no. 87; a = 6.3519(1), c = 7.9176(2) angstrom; Z = 2, R(F-2) = 0.1162). The crystal structure of Mg(NH3)(2)(N-3)(2) is related to that of SnF4. It consists of planes built up from corner sharing Mg(NH3)2(N3)4 octahedra connected equatorially over their four azide bridges with the ammonia ligands being in trans position. IR data were collected and interpreted in accordance with the structural data. 2005-77 ?? Marinkovic, BA Jardim, PM de Avillez, RR Rizzo, F Negative thermal expansion in Y2Mo3O12 SOLID STATE SCIENCES 7, 2005, 1377-1383 The crystal structure of Y2Mo3O12 was refined by the Rietveld method for 130 degrees C as orthorhombic with space group Pbcn (No. 60). It is isostructural to Fe2Mo3O12 and consists of vertex sharing YO6 and MoO4 building polyhedra. Y2Mo3O12 has very high negative thermal expansion along all three crystallographic directions in the 130-900 degrees C temperature range. The overall linear coefficient of thermal expansion (alpha(1) = alpha(v)/3) is -1.26 x 10(-5) degrees C. Water molecules enter freely in Y2Mo3O12 microchannels and seem to have a role in partial amorphization of this compound at room temperature. 2005-78 Littner, A Francois, M Tobola, J Elkaim, E Malaman, B Vilasi, M Molten glass corrosion resistance of new Mo-Ru-Si compounds MATERIALS AND CORROSION-WERKSTOFFE UND KORROSION 56, 2005, 796-800. AB In spite of a very promising potential for a large field of high temperature applications, MoSi2 shows only a limited resistance against molten glass corrosion. Efforts to improve the performance of MoSi2-based materials led to the investigation of the Mo-Ru-Si phase diagram. The isothermal section at 1673 K revealed five new intermetallics with original structures. The crystallographic study of two of them was made using standard and synchrotron X-ray measurements combined with KKR (Korringa-Kohn-Rostoker) calculations. The use of such total energy electronic structure calculations was helpful in order to localize accurately Mo and Ru in the new compound beta-Mo26Ru47Si27. This compound crystallizes in P4/mmm space group with a = 9.2164(l) angstrom, c = 2.88721 (1) angstrom, Dx = 9.69(1) g/cm(3). The structure has been refined by the Rietveld method down to R-p = 1. 1 %, R-B = 12.0 %, R-F = 8.7% for 6814 ob-served data and 271 independent reflections. Moreover, electrochemical techniques enabled the determination of the redox properties of the new intermetallic compounds. It has been shown that, in contact with molten glass at 1623 K, Mo-Ru-Si compounds were subjected to electrochemical reactions leading to the simultaneous oxidation of silicon and molybdenum. The progressive superficial depletion of Si and Mo resulted in the more or less rapid formation of a thick, porous and low adherent Ru-layer. Consequently, the results showed that Ru-additions had no positive effect on the molten glass corrosion resistance of MoSi2-based materials. The formation of a porous Ru-layer should even accelerate the degradation kinetics through galvanic coupling occurring between the superficial layer and the bulk material. 2005-79 ??? Li, LY Li, GB Wang, YX Liao, FH Lin, JH Bismuth borates: Two new polymorphs of BiB3O6 INORGANIC CHEMISTRY 44, 2005, 8243-8248. Two new polymorphs of BiB3O6 were identified at low temperatures using boric acid as a flux. Unlike alpha-BiB3O6, which crystallizes in a noncentrosymmetric space group and, thus, shows exceptional nonlinear optical (NLO) properties, beta-BiB3O6 (I) and gamma-BiB3O6 (II) crystallize in the centrosymmetric space group P2(1)/n with the following lattice parameters: a = 14.1664(I), b = 6.7514(I), c = 4.4290(I) angstrom, beta = 102.125(I)degrees for I; and a = 8.4992(I), b = 11.7093(I), c = 4.2596(I) angstrom, beta = 121.141(I)degrees for II. However, from the structural point of view, the three polymorphs of BiB3O6 are closely related. The structure of beta-BiB3O6 (I) contains a 2-dimensional borate layer, which could be considered to be an intralayered additive product of alpha-BiB3O6. On the other hand, the 3-dimensional borate framework in gamma-BiB3O6 (II) could be considered to be an interlayered additive product of beta-BiB3O6 (I). According to the synthesis experiments and calculated density, it is proposed that compounds I and II should be the low-temperature (high-pressure) polymorphs of BiB3O6. 2005-80 ??? Oliveira, MF Kycia, SW Gomez, A Kosar, AJ Bohle, DS Hempelmann, E Menezes, D Vannier-Santos, MA Oliveira, PL Ferreira, ST Structural and morphological characterization of hemozoin produced by Schistosoma mansoni and Rhodhius prolixus FEBS LETTERS 579, 2005, 6010-6016. Hemozoin (Hz) is a heme crystal produced upon the digestion of hemoglobin (Hb) by blood-feeding organisms as a main mechanism of heme disposal. The structure of Hz consists of heme dimers bound by reciprocal iron-carboxylate interactions and stabilized by hydrogen bonds. We have recently described heme crystals in the blood fluke, Schistosoma mansoni, and in the kissing bug, Rhodnius prolixus. Here, we characterized the structures and morphologies of the heme crystals from those two organisms and compared them to synthetic P-hematin (beta H). Synchrotron radiation X-ray powder diffraction showed that all heme crystals share the same unit cell and structure. The heme crystals isolated from S. mansoni and R. prolixus consisted of very regular units assembled in multicrystalline spherical structures exhibiting remarkably distinct surface morphologies compared to beta H. In both organisms, Hz formation occurs inside lipid droplet-like particles or in close association to phospholipid membranes. These results show, for the first time, the structural and morphological characterization of natural Hz samples obtained from these two blood-feeding organisms. Moreover, Hz formation occurring in close association to a hydrophobic environment seems to be a common trend for these organisms and may be crucial to produce very regular shaped phases, allowing the formation of multicrystalline assemblies in the guts of S. mansoni and R. prolixus. 2005-81 Barros-Garcia, FJ Bernalte-Garcia, A Cumbrera, FL Lozano-Vila, AM Luna-Giles, F Melendez-Martinez, JJ Ortiz, AL Synthesis, molecular characterization by infrared spectroscopy, and crystal structure determination by X-ray powder diffractometry of [ZnCl2(TdTz)] [TdTz=2-(3,4-dichlorophenyl)imino-N-(2-thiazin-2-yl)thiazolidine] POLYHEDRON 24, 2005, 1975-1982. The title zinc(II) complex, dichloro[2-(3,4-dichlorophenyl)imino-kappa N-N-(2-thiazin-kappa N-2-yl)thiazolidine]zinc(II), was synthesized in the form of small crystals unsuitable for structure determination by X-ray single-crystal diffractometry. It was therefore characterized firstly in the solid state by elemental analysis and infrared spectroscopy, and then its crystal structure was determined by X-ray powder diffractometry. The procedure followed to resolve the crystal structure used direct-space methods with a 'MonteCarlo/parallel tempering' search algorithm, where the starting configuration was obtained by means of infrared spectroscopy and molecular mechanics. A final refinement of the crystal structure was performed using the Rietveld method. It was found that the environment around the zinc(II) ion may e described as a distorted tetrahedral geometry, with the metallic atom coordinated to two chlorine atoms [Zn-Cl(1) = 2.158(5) angstrom; Zn-Cl(2) = 2.145(4) angstrom], one imino nitrogen [Zn-N(3) = 2.237(4) angstrom] and one thiazine nitrogen [Zn-N(1) = 2.273(5) angstrom]. In addition, we also report in this study the crystal structure of the 2-(3,4-dichlorophenyl)imino-N-(2-thiazin-2-yl)thiazolidine (TdTz) ligand determined by X-ray single-crystal diffractometry. 2005-82 Miller, SR Lear, E Gonzalez, J Slawin, AMZ Wright, PA Guillou, N Ferey, G Synthesis and structure of the framework scandium methylphosphonates ScF(H2O)CH3PO3 and NaSc(CH3PO3)(2)center dot 0.5H(2)O DALTON TRANSACTIONS 20, 2005, 3319-3325. Two framework scandium methylphosphonates have been prepared hydrothermally and their structures solved. ScF(H2O) CH3PO3 is a non-porous solid built up from - ScF - chains linked by methylphosphonate groups. The ScO4F2 octahedra are completed by a coordinated water molecule. NaSc(CH3PO3)(2) center dot 0.5H(2)O was solved ab initio from high-resolution synchrotron X-ray powder diffraction data. It has a fully connected, negatively charged scandium phosphonate framework where ScO6 octahedra share vertices with PO3CH3 groups. The solid contains charge balancing sodium cations, coordinated by a water molecule, which may be reversibly removed and adsorbed. The structure of the perdeuterated, dehydrated solid has been refined against neutron powder diffraction data collected at 2.5 K, showing the CD3 groups in a fully staggered orientation with respect to the phosphonate oxygen atoms. 2005-83 Belik, AA Azuma, M Matsuo, A Whangbo, MH Koo, HJ Kikuchi, J Kaji, T Okubo, S Ohta, H Kindo, K Takano, M Investigation of the crystal structure and the structural and magnetic properties of SrCu2(PO4)(2) INORGANIC CHEMISTRY 44, 2005, 6632-6640. SrCu2(PO4)(2) was prepared by the solid-state method at 1153 K. Its structure was solved by direct methods in the space group Pccn (No. 56) with Z = 8 from synchrotron X-ray powder diffraction data measured at room temperature. Structure parameters were then refined by the Rietveld method to obtain the lattice parameters, a = 7.94217(8) angstrom, b = 15.36918(14) angstrom, and c = 10.37036(10) angstrom. SrCu2(PO4)(2) presents a new structure type and is built up from Sr2O16 and Cu1Cu(2)O(8) units with Cu1 (...) Cu2 = 3.256 angstrom. The magnetic properties of SrCu2(PO4)(2) were investigated by magnetic susceptibility, magnetization up to 65 T, Cu nuclear quadrupole resonance (NQR), electron-spin resonance, and specific heat measurements. With spin-dimer analysis, it was shown that the two strongest spin-exchange interactions between Cu sites result from the Cu1-0 (...) O-Cu2 and Cu2-0 (...) O-Cu2 super-superexchange paths with Cu1 (...) Cu2 = 5.861 angstrom and Cu2 (...) Cu2 = 5.251 angstrom, and the superexchange associated with the structural dimer Cu1Cu2O(8) is negligible. The magnetic susceptibility data were analyzed in terms of a linear four-spin cluster model, Cu1-Cu2-Cu2-Cu1 with -2J(1)/k(B) = 82.4 K for Cu1-Cu2 and -2J(2)/k(B) = 59 K for Cu-Cu2. A spin gap deduced from this model (Delta/k(B) = 63 K) is in agreement with that obtained from the Cu NQR data (Delta/k(B) = 65 K), A one-half magnetization plateau was observed between approximately 50 and 63 T at 1.3 K. Specific heat data show that SrCu2(PO4)(2) does not undergo a long-range magnetic ordering down to 0.45 K. SrCu2(PO4)(2) melts incongruently at 1189 K. We also report its vibrational properties studied with Raman spectroscopy. 2005-84 Galli, S Masciocchi, N Cariati, E Sironi, A Barea, E Haj, MA Navarro, JAR Salas, JM Quest for second-harmonic-generation-active coordination polymers: Synthesis and properties of silver(I) pyrimidinolates CHEMISTRY OF MATERIALS 17, 2005, 4815-4824. In the search for coordination compounds showing significant second harmonic generation (SHG) activity, reaction of Ag(I) ions with the 4-hydroxypyrimidine (4-Hpymo) and 5-nitro-2-hydroxypyrimidine (HNP) ligands generated four crystalline ID polymers, Ag(4-pymo)center dot nH(2)O (n = 2.5, 0), Ag(NP)(NH3), and Ag(NP), the latter two crystallizing in acentric space groups. Their synthesis, complete characterization, and structural determination, by conventional single-crystal and laboratory X-ray powder diffraction methods, are presented and discussed in the frame of diazaaromatic-ligand- and metal-containing species. XRPD has also allowed the detection of the polyhydrated, elusive Ag(4-pymo)center dot nH(2)O (n = 2, 3) species. Powders of Ag(NP) have shown an SHG activity close to that of standard urea. By applying the geometrical model proposed by Zyss, it is shown that the NP ligand is a highly promising chromophore, the oxo and nitro functionalities cooperatively promoting a high hyperpolarizability. 2005-85 ??? Staunton, E Andreev, YG Bruce, PG Structure and conductivity of the crystalline polymer electrolyte beta-PEO6 : LiAsF6 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127, 2005, 12176-12177. 2005-86 ??? Li, LY Li, GB Wang, YX Liao, FH Lin, JH Bismuth borates: One-dimensional borate chains and nonlinear optical properties CHEMISTRY OF MATERIALS 17, 2005, 4174-4180. Three bismuth borates, Bi[B4O6(OH)(2)]OH (I), BiB2O4F (II), and Bi-3[B6O13(OH)] (III), were obtained in boric acid flux at low temperatures and their structures were determined by using single-crystal and powder X-ray diffraction techniques. All these three bismuth borates contain one-dimensional borate chains and crystallize in noncentrosymmetric space groups. I is a hydrated borate, crystallizing, in the space group PI with lattice constants a = 4.300(1) angstrom, b = 8.587(2) angstrom, c = 10.518(2) angstrom, alpha = 113.11(3)', 100.50(3)degrees, and beta = 90.36(3)degrees, and the borate chain consists of a 3-ring (2BO(3) + BO4) and a BO3 group. II is a fluoroborate, which crystallizes in the trigonal space group P3(2) with a = 6.7147(1) angstrom and c = 6.4688(1) angstrom, and the borate anion is a 3-fold helix chain formed by extensive linkage of three-membered borate rings (3BO(4)). III is also a hydrated borate with a structure that is closely related to 11, in which one-sixth of the borate groups are in triangular geometry (BOA which reduces the symmetry to P1, a = 6.6257(1) angstrom, b =6.6238(1) angstrom, c = 6.6541(1) angstrom, and alpha = 89.998(3)degrees, beta = 89.982(2)degrees, and gamma = 119.992(2)degrees. All these three bismuth borates exhibit nonlinear optical (NLO) properties. 2005-87 Dorset, DL Kennedy, GJ Crystal structure of MCM-70: A microporous material with high framework density JOURNAL OF PHYSICAL CHEMISTRY B 109, 2005, 13891-13898. The crystal structure of the borosilicate MCM-70 (siliceous framework formula Si12O24) was determined from synchrotron powder diffraction data with the program FOCUS. The framework crystallizes in space group Pmn2(1), where a = 13.663, b = 4.779, c = 8.723 angstrom, and forms ID ellipsoidal 10-ring channels with the following dimensions: 5.0 x 3.1 angstrom. Rietveld refinement of the model against synchrotron powder data from solvated material gives Rwp = 0.15, R(F-2) = 0.11. In addition to the four tetrahedral sites and seven framework oxygens, one potassium position is found during this refinement. Because of the unreasonable geometry of five putative extraframework oxygen sites, another synchrotron pattern was obtained from a dehydrated specimen. A refinement in space group P1n1 (removing the mirror operation of Pmn2(1)), where a = 13.670, b = 4.781, c = 8.687 angstrom, and beta = 90.24 degrees, verified that the previous framework geometry is preserved as well as the potassium position. One extraframework oxygen was located that would yield a reasonable K-O distance. The existence of potassium is verified by electron energy dispersive spectroscopic measurements as well as quantitative elemental analysis. (There are approximately 2.35 K sites per 12 Si in the unit cell.) It is likely that the constricted channels occlude KOH. B-11 and Si-29 MAS NMR measurements indicate a framework SiO2/B2O3 of approximately 40:1, which is consistent with a wavelength dispersive spectroscopic measurement. The silicate framework density is 2.10 gm/cm(3). The resulting framework density for T sites, 21.1, is unusually high for a zeolite, just below the value for paracelsian (21.4) or scapolite (21.8), each of which also has a smallest four-ring loop. The H-1 -> Si-29 CP MAS measurements suggest sample heterogeneity, that is, a portion of the sample that is strongly coupled to hydrogen and efficiently cross polarizes and another portion that does not. 2005-88 Li, LY Liao, FH Li, GB Lin, JH Synthesis and structure of a novel hydrated rare earth polyborate, Ln[B5O8(OH)(2)] (Ln=Pr, Nd) CHINESE JOURNAL OF INORGANIC CHEMISTRY 21, 2005, 949-954. A novel hydrated rare earth polyborate, Ln[B5O8(OH)(2)] (Ln=Pr, Nd) has been synthesized by using boric acid as a flux at 200 degrees C. Its crystal structure is established by powder X-ray diffraction technique. Ln[B5O8(OH)(2)] crystallizes in monoclinic space groupP2(1)/c. The title compounds consist of a double three-membered ring composed of three BO4 and two BO3 groups as the fundamental building block. The FBB shares four common oxygen atoms with the adjacent FBBs, producing a borate layer containing nine-membered borate ring window, of which the rare earth cations are located around the center. The Ln(3+) cations are coordinated with ten oxygen atoms from the nine-membered ring window and the adjacent borate layer. The borate layers are stacked along the b axis and are interlinked by the Ln-O bond. 2005-89 Irran, E Jurgens, B Schmid, S Schnick, W Synthesis, crystal structure determination from X-ray powder diffractometry and vibrational spectroscopic properties of Mg[N(CN)(2)](2) center dot 4H(2)O ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 1512-1515. Magnesium dicyanamide tetrahydrate Mg[N(CN)(2)](2)(.)4 H2O was synthesized by aqueous ion exchange starting from Na[N(CN)(2)] and Mg(NO3)(2)(.)6 H2O. The crystal structure was solved and refined on the basis of powder X-ray diffraction data (P-21/c, Z = 2, a 737.50(2), b = 732.17(1), c = 971.67(2) pm, beta = 98.074(1)degrees, wR(P) = 0.059, R-P = 0.046, R-F = 0.075). In the crystal there are neutral complexes [Mg[N(CN)(2)](2)(H2O)(4)] Which arc only connected via hydrogen bonds. Above 40 degrees C the tetrahydrate decomposes into anhydrous Mg[N(CN)(2)](2). 2005-90 Barbier, J Penin, N Cranswick, LM Melilite-type borates Bi2ZnB2O7 and CaBiGaB2O7 CHEMISTRY OF MATERIALS 17, 2005, 3130-3136. The bismuth borates Bi2ZnB2O7 and CaBiGaB2O7 have been synthesized by solid-state reactions at temperatures in the 650-825 degrees C range at 1 atm pressure. These compounds are the only synthetic diborate members of the melilite family, A(2)XZ(2)O(7), in which layers of A cations alternate with XZ(2)O(7) tetrahedral layers. Except for CdBiGaB2O7, the synthesis of other substituted bismuth borate melilites has been unsuccessful. The crystal structures of Bi2ZnB2O7 and CaBiGaB2O7 have been determined by powder X-ray diffraction and refined by the Rietveld method using powder neutron diffraction data. CaBiGaB2O7 adopts the regular tetragonal melilite structure (P $(4) over bar $2(1)m space group, Z = 2) containing B2O7 tetrahedral dimers. The refinement of split eight-coordinated sites for the Ca2+ and Bi3+ interlayer cations suggests the presence of additional disorder. Bi2ZnB2O7 adopts a unique orthorhombic melilite superstructure (Pba2 space group, Z = 4) containing both tetrahedral B2O7 and triangular B2O5 dimers. The Bill cations occupy two distinct interlayer sites with strongly asymmetric 6-fold coordination environments. The preliminary measurement of second harmonic generation efficiencies (d(eff)) of powder samples has yielded values of 4.0 (Bi2ZnB2O7) and 1.6 (CaBiGaB2O7) relative to a KH2PO4 standard. 2005-91 Ikeda, T Itabashi, K RMA-3: synthesis and structure of a novel Rb-aluminosilicate zeolite CHEMICAL COMMUNICATIONS iss 21, 2005, 2753-2755. RMA-3 (Rubidium Microporous Aluminosilicate-3) was hydrothermally synthesized from rubidium-aluminosilicate gels without using any organic or inorganic additives, and its structure determined by XRD Rietveld analysis was confirmed as a novel framework topology containing two 8-membered ring pore-openings with dimensions of 0.49 x 0.37 nm and 0.34 x 0.38 nm. 2005-92 Chi, LS Swainson, I Cranswick, L Her, JH Stephens, P Knop, O The ordered phase of methylammonium lead chloride CH3ND3PbCl3 JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 1376-1385. The perovskite-structured compound methylammonium lead chloride orders into a low-temperature phase of space group Pnma, in which at 80 K each of the orthorhombic axes a = 11.1747(2) &ANGS;, b = 11.3552(1) &ANGS;, and c = 11.2820(1) &ANGS; is doubled with respect to the room temperature disordered cubic phase (a = 5.669 &ANGS;). The structure was solved by ab initio methods using the programs EXPO and FOX. This unusual cell basis for space group Pnma is not that of a standard tilt system. This phase, in which the methylammonium ions, are ordered shows distorted octahedra. The octahedra possess a bond angle variance of 60.663(&DEG; 2) and a quadratic elongation of 1.018, and are more distorted than those in the ordered phase of methylammonium lead bromide. There is also an alternating long and short Pb-Cl bond along a, due to an off-center displacement of Pb within the octahedron. This suggests that the most rigid unit is actually the methylammonium cation, rather than the PbCl6 octahedra, in agreement with existing spectroscopic data. 2005-93 Drache, M Roussel, P Conflant, P Wignacourt, JP Bi17Yb7O36 and BiYbO3 crystal structures. Characterization of thulium and lutetium homologous compounds SOLID STATE SCIENCES 7, 2005, 269-276. Two new compounds Bi17Yb7O36 and BiYbO3 which were recently evidenced in the Bi2O3-Yb2O3 system, have been characterized and their structure determined from X-ray diffraction powder data using the Rietveld method in an orthorhombic and a triclinic lattice, respectively. The thulium and lutetium homologous compounds have been prepared for the first time. They are isostructural to the ytterbium homologous. The six compounds have been characterized versus temperature by DTA, X-ray thermodiffractometry, and they systematically show a transformation from their low temperature form, to a delta-Bi2O3-type phase, occurring on heating. For Bi(17)Ln(7)O(36), the delta-type phase is obtained, directly with Ln = Lu (870 degrees C) and Yb (855 degrees C), and only after an intermediate biphasic orthorhombic-cubic mixture in the range 780-825 degrees C for Ln = Tm. For BiLnO(3), there is a large two-phased domain (delta-Bi2O3 + Ln(2)O(3) related phases) from 955 to 1100 degrees C for Lu, 970 to 1200 degrees C for Yb and 980 to 1270 degrees C for Tm. The lattice constants thermal expansion coefficients have been determined from the cell parameters evolutions versus temperature. The conductivity properties of the Bi(17)Ln(7)O(36) series, which could be obtained as ceramic pellets after sintering in the stability range of their low-temperature forms, have been investigated. 2005-94 Majzlan, J Botez, C Stephens, PW The crystal structures of synthetics Fe-2(SO4)(3)(H2O)(5) and the type specimen of lausenite AMERICAN MINERALOGIST 90, 2005, 411-416. An iron sulfate of nominal composition Fe-2(SO4)(3)(H2O)(5) has been synthesized and its structure determined and refined by high resolution powder diffraction using synchrotron radiation. The structure consists of corrugated slabs in which iron octahedra are linked by sulfate tetrahedra in the monoclinic space group P2(1)/m with lattice parameters a = 10.711(1), b = 11.085(1), and c = 5.5747(5) Angstrom, beta = 98.853(3)degrees. We compare these results with the type specimen of lausenite from Jerome, Arizona, which has monoclinic lattice parameters a = 10.679(2), b = 11.053(3), and c = 5.567(1) Angstrom, beta = 98.89(1)degrees. Weight loss experiments show that it is currently a pentahydrate, despite earlier reports that lausenite is a hexahydrate. We argue that our synthetic material provides a structure determination for the type specimen of lausenite. 2005-95 Jurgens, B Irran, E Schnick, W Synthesis and characterization of the rare-earth dicyanamides Ln[N(CN)(2)](3) with Ln = La, Ce, Pr, Nd, Sm, and Eu JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 72-78. The rare-earth dicyanamides Ln[N(CN)(2)](3) (Ln = La, Ce, Pr, Nd, Sm, Eu) were obtained via ion exchange in aqueous medium and subsequent drying: The crystal structures were solved and refined based on X-ray powder diffraction data and they were found to be isotypic: Ln[N(CN)(2)](3); Cmem (no. 63), Z = 4, Ln = La: a = 799.88(9) pm, b = 11 58.2(1) pin, c = 1026.7(1) pm; Cc: a = 794.94(3) pm, b = 1152.15(4)pm, c = 1020.96(4)pm; Pr: a = 790.45(5)pm, b = 1146.19(6)pm, c = 1016.74(6)pm; Nd: a 787.79(3)pm, b = 1144.59(4)pm, c = 1015.54(4)pm; Sm: a = 781.30(5)pm, b = 1138.64(6)pm, c = 1012.04(5)pm; Eu: a 776.7(1)pm, b = 113 5. 1 (1) pm, c = 10 1 3.7(1) pm). The compounds represent the first dicyanamides with trivalent cations. The Ln(3+) ions are coordinated by three bridging N atoms and six terminal N atoms of the dicyanamide ions forming a three capped trigonal prism. The structure type is related to that of PuBr3. The novel compounds Ln[N(CN)(2)](3) have been characterized by IR and Raman spectroscopy (Ln = La) and the thermal behavior has been monitored by differential scanning calorimetry (Ln = Ce, Nd, Eu). 2005-96 ?? Li, ZF Sun, JL Wang, YX You, LP Lin, JH Structural and magnetic properties of Ba3La3Mn2W3O18 JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 114-119. A quaternary phase, Ba3La3Mn2W3O18, was synthesized in reduced atmosphere (5% H-2/Ar) at 1200degreesC and characterized by using powder X-ray diffraction, electron diffraction and high resolution TEM. Ba(3)La(3)Mn(2)W3O(18) crystallizes in rhombohedral space group R $(3) over bar $m with the cell parameters, a = 5.7371(1) Angstrom and c = 41.8336(5) Angstrom, and can be attributed to the n = 6 member in the B-site deficient perovskite family, A(n)B(n)-O-1(3n). The structure can be described as close-packed [La/BaO3] arrays in the sequence of (hcccch)(3), wherein the B-site cations, W and Mn, occupy five octahedral layers in every six octahedral layers, which leave a vacant octahedral layers separating the 5-layer perovskite blocks. The B-cation layers in the perovskite block alternate along the c-axis in a sequence of W6+-Mn2+ -W5+ -Mn2+- W6+. The bond valence calculation and optical reflection spectrum confirm the presence of W5+. This compound behaves paramagnetically in wide temperature range and weak antiferromagnetic interaction only occurs at low temperatures. 2005-97 Tyutyunnik, AP Zubkov, VG Krasil'nikov, VN Svensson, G Sayagues, MJ Crystal structure of K2V8O21 and Tl2V8O21 SOLID STATE SCIENCES 7, 2005, 37-43. The crystal structures of K2V8O21 and Tl2V8O21 have been determined and refined, using both neutron and X-ray powder diffraction data. K2V8O21 (TI2V8O21) crystallises in the monoclinic space group C2/m (C2/m) with the unit cell parameters a = 14.9402(2) (15.1405(4)) Angstrom, b = 3.61823(4) (3.61309(6)) Angstrom, c = 14.7827(2) (14.9712(2)) Angstrom and beta = 91.072(1)degrees (89.967(2)degrees). The structures consist of VO6 octahedra and VO5 pyramids forming [V8O21](2-) units running along the b axis. These units can then be divided into three columns: (i) two edge-sbaring VO5 pyramids, (ii) columns of rock-salt type structure and (iii) single chains of VO5 pyramids. The KM ions are found in tunnels formed by the [V8O2](2-) units. 2005-98 Barrier, N Michel, C Maignan, A Hervieu, M Raveau, B CaMn4O8, a mixed valence manganite with an original tunnel structure JOURNAL OF MATERIALS CHEMISTRY 15, 2005, 386-393. A new mixed valent manganite CaMn4O8 with an original tunnel structure has been synthesized. The host lattice of this oxide has been determined by X-ray powder diffraction, using ab initio methods, and by high resolution electron microscopy. It consists of single and triple chains of edge-sharing MnO6 octahedra, interconnected through their apices. The [Mn4O8](infinity) framework delimits three types of tunnels: six-sided ("H") and eight-sided ("8") where sit the Ca2+ cations, and empty rutile-like tunnels ("R"). The analysis of the Mn-O inter-atomic distances shows that this structure could also be described from the association of only single chains of edge-sharing MnO6 octahedra, with single chains of edge-sharing MnO5 pyramids, and evidences a high tendency of manganese to charge ordering. Nanostructural mechanisms investigated by electron microscopy also allow the structure to be described in terms of single bricks of four Mn polyhedra, and evidence twinning and intergrowth phenomena as well as local ordering of calcium in the tunnels. The magnetic measurements show strong antiferromagnetic fluctuations at low temperature, whereas the low value of T-N similar to 90 K indicates that the antiferromagnetic superexchange is weak in this oxide. 2005-99 Schmidt, MU Ermrich, M Dinnebier, RE Determination of the structure of the violet pigment C22H12Cl2N6O4 from a non-indexed X-ray powder diagram ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 37-45. The violet pigment methylbenzimidazolonodioxazine, C22H12Cl2N6O4 (systematic name: 6,14-dichloro- 3,11-dimethyl- 1,3,9,11-tetrahydro-5,13-dioxa-7,15-diazadiimidazo[ 4,5-b: 4',5'-m] pentacene-2,10-dione), shows an X-ray powder diagram consisting of only ca 12 broad peaks. Indexing was not possible. The structure was solved by global lattice energy minimizations. The program CRYSCA [ Schmidt & Kalkhof ( 1999), CRYSCA. Clariant GmbH, Pigments Research, Frankfurt am Main, Germany] was used to predict the possible crystal structures in different space groups. By comparing simulated and experimental powder diagrams, the correct structure was identified among the predicted structures. Owing to the low quality of the experimental powder diagram the Rietveld refinements gave no distinctive results and it was difficult to prove the correctness of the crystal structure. Finally, the structure was confirmed to be correct by refining the crystal structure of an isostructural mixed crystal having a better X-ray powder diagram. The compound crystallizes in P (1) over bar, Z = 1. The crystal structure consists of a very dense packing of molecules, which are connected by hydrogen bridges of the type N - H ... O=C. This packing explains the observed insolubility. The work shows that crystal structures of molecular compounds may be solved by lattice energy minimization from diffraction data of limited quality, even when indexing is not possible. 2005-100 Brazdova, V Ganduglia-Pirovano, MV Sauer, J Crystal structure and vibrational spectra of AlVO4. A DFT study JOURNAL OF PHYSICAL CHEMISTRY B 109, 2005, 394-400. We present periodic density functional calculations within the generalized gradient approximation (Perdew-Wang 91) on structure and vibrational properties of bulk AlVO4. The optimized structure agrees well with crystallographic data obtained by Rietveld refinement (the mean absolute deviation of bond distances is 0.032 A), but the deviations are larger for the lighter oxygen atoms than for the heavier Al and V atoms. All observed bands in the Raman and IR spectrum have been assigned to calculated harmonic frequencies. Bands in the 1020-900 cm(-1) region have been assigned to V-O-(2) stretches in V-O-(2)-Al bonds. The individual bands do not arise from vibrations of only one bond, not even from vibrations of several bonds of one VO4 tetrahedron. The results confirm that vibrations around 940 cm(-1) observed for vanadia particles supported on thin alumina film are V-O-Al interface modes with 2-fold coordinated oxygen atoms in the V-O-(2)-Al interface bonds. 2005-101 Sperandeo, NR Karlsson, A Cuffini, S Pagola, S Stephens, PW The crystal structure and physicochemical characteristics of 2-hydroxy-N-[3(5)-pyrazolyl]-1,4-naphthoquinone-4-imine, a new antitrypanosomal compound AAPS PHARMSCITECH 6, iss 4, 2005. This study was designed to investigate the physical characteristics and crystalline structure of 2-hydroxy-N-[3(5)pyrazolyl]-1,4-naphthoquinone-4-imine (PNQ), a new active compound against Trypanosoma cruzi, the causative agent of American trypanosomiasis. Methods used included differential scanning calorimetry, thermogravimetry, hot stage microscopy, polarized light microscopy (PLM), Fourier-transform infrared (FTIR) spectroscopy, and high-resolution X-ray powder diffraction (HR-XRPD). According to PLM and HR-XRPD data, PNQ crystallized as red oolitic crystals (absolute methanol) or prisms (dimethyl sulfoxide [DMSO]-water) with the same internal structure. The findings obtained with HR-XRPD data (applying molecular location methods) showed a monoclinic unit cell [a = 18.4437(1) angstrom, b = 3.9968(2) angstrom, c = 14.5304(1) angstrom, alpha = 90, beta = 102.71(6)degrees, = 90 degrees, V = 1044.9(1) angstrom(3), Z = 4, space group P2(1)/c], and a crystal structure (excluding H-positions) described by parallel layers in the direction of the b-axis, with molecules held by homochemical (phenyl-phenyl and pyrazole-pyrazole) van der Waals interactions. In addition, FTIR spectra displayed the NH-pyrazole stretch overlapped with the OH absorption at 3222 cm(-1), typical of -NH and -OH groups associated through H-bondings; and a carbonyl stretching absorption at 1694 cm(-1), indicating a non-extensively H-bonded quinonic C=O, which was in accordance with the solved crystal structure of PNQ. The existence of such cohesive forces shed light on the thermoanalytical data, which revealed that PNQ is a stable solid, unaffected by oxygen that decomposed without melting above 260 degrees C. 2005-102 Sofina, N Dinnebier, R Jansen, M The crystal structure of disodium phosphonate, Na2HPO3 ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 2994-2996. Anhydrous disodium phosphonate, Na2HPO3, was prepared by dehydration of its pentahydrate. The crystal structure of Na2HPO3 was solved from high resolution X-ray powder diffraction data (P2(1)/n; Z = 4; a 9.6987(1), b = 6.9795(1), c = 5.0561 (1) angstrom, beta = 92.37(1)degrees; V = 341.97(1) angstrom(3)). The crystal structure consists of two types of sodium-oxygen polyhedra, which are connected via common edges and vertices forming layers perpendicular to [100]. These Na(1)- and Na(2)-layers are interlinked via common edges, forming in a 3D-framework. The resulting topology is providing oxygen arrangements that please the coordinative requirement of phosphorus(III). 2005-103 Helliwell, JR Helliwell, M Jones, RH Ab initio structure determination using dispersive differences from multiple-wavelength synchrotron-radiation powder diffraction data ACTA CRYSTALLOGRAPHICA SECTION A 61, 2005, 568-574. The purpose of this paper and a test case study is to assess a method of ab initio structure solution from powder diffraction data using f' difference techniques. A theoretical foundation for the approach used is first provided. Then, with a test case ( nickel sulfate hexahydrate), it is shown that both the position of the anomalous scatterer (Ni) can be determined and the structure can be developed in full. Specifically, synchrotron-radiation data were collected at two wavelengths close to the K edge for Ni and three wavelengths remote from the Ni absorption edge, at 1.3, 1.8 and 2.16 angstrom. These five wavelengths then allowed various combinations to be tried to establish which wavelength pairs gave the optimum signal in the Patterson maps using dispersive amplitude differences. The initial phases derived from the metal-atom position then allowed the structure to be fully developed by difference Fourier cycling. The relevance of these developments to structure-solution possibilities for proteins via powder dispersive difference data is then outlined. 2005-104 Dinnebier, RE Nuss, H Jansen, M The crystal structures of solvent-free alkali-metal squarates from powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE 220, 2005, 954-961. The crystal structures of solvent-free lithium, sodium, rubidium, and cesium squarates have been determined from high resolution synchrotron and X-ray laboratory powder patterns. Crystallographic data at room temperature of Li2C4O4: a = 7.1073(3) angstrom, b = 9.5627(4) angstrom, c = 3.2973(1) angstrom, beta = 101.11(1)degrees, V = 219.91 (1) angstrom(3), monoclinic, C2/m, Z = 2, Na2C4O4: a 3.4925(1) angstrom(3), b = 6.8152(1) angstrom, c = 10.3525(2) angstrom, beta = 91.56(1)degrees V = 246.32(1) angstrom(3), monoclinic, P2(1)/c, Z = 2; Rb2C4O4: a = 10.7908(5) angstrom, b = 6.8494(3) angstrom, c = 4.4521(2) angstrom, beta = 92.39(0), V = 328.77(4) angstrom(3), monoclinic, C2/m, Z = 2; Cs2C4O4: a = 1.1768(3)angstrom, b = 7.0453(2)angstrom, c = 4.7424(1) angstrom, beta = 92.89(1)degrees; V = 372.97(4) angstrom(3), monoclinic, C2/m, Z = 2. The packing features of lithium squarate can be deduced from the AlB2 structure type, while sodium, rubidium, and cesium squarate are related to the CdI2 type. The relation between the two types of crystal structures of the squarate dianion is discussed. 2005-105 Dinnebier, RE Nuss, H Jansen, M Disodium rhodizonate: a powder diffraction study ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 61, 2005, M2148-M2150. The crystal structure of the title compound, disodium 1,2,3,4-tetraoxo-5-cyclohexene-5,6-diolate, 2Na(+) center dot C6O62+, is built up of alternating layers of hexagonally packed Na+ cations and rhodizonate dianions. The rhodizonate dianion has a slightly twisted conformation. 2005-106 Kirik, SD Mulagaleev, RF Blokhin, AI [Pd-8(CH3COO)(8)(NO)(8)]: solution from X-ray powder diffraction data ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 61, 2005, M445-M447. The water-insoluble title compound, octakis(mu-acetato-kappa(2)O:O) octakis(mu-nitroso-kappa(2)N:O) octapalladium(II), [Pd-8(CH3COO)(8)(NO)(8)], was precipitated as a yellow powder from a solution of palladium nitrate in nitric acid by adding acetic acid. Ab initio crystal structure determination was carried out using X-ray powder diffraction techniques. Patterson and Fourier syntheses were used for atom locations, and the Rietveld technique was used for the final structure refinement. The crystal structure is of a molecular type. The skeleton of the [Pd-8(CH3COO)(8)(NO)(8)] molecule is constructed as a tetragonal prism with Pd atoms at the vertices. The eight NO- groups are in bridging positions along the horizontal edges of the prism. The N and O atoms of each nitroso group coordinate two different Pd atoms. The vertical edges present Pd center dot center dot center dot Pd contacts with a short distance of 2.865 (1) angstrom. These Pd atoms are bridged by a pair of acetate groups in a cis orientation with respect to each other. The complex has crystallographically imposed 4/m symmetry; all C atoms of the acetate groups are on mirror planes. The unique Pd atom lies in a general position and has square-planar coordination, consisting of three O and one N atom. 2005-107 Dinnebier, RE Nuss, H Jansen, M Anhydrous CuC4O4, a channel structure solved from X-ray powder diffraction data ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 2328-2332. The crystal structure of the new anhydrous metal squarate CUC4O4 was solved from laboratory X-ray powder diffraction data. It crystallizes in the monoclinic space group I2/a (no. 15) with the lattice parameters a = 5.6747(1), b = 8.9394(4), c = 9.4987(4) angstrom und beta = 94.372(2)degrees at ambient conditions (Z = 4, R-F(2) = 8.24%). The crystal structure can be reduced to a defect variant of the AIB(2) type of structure ([C4O4][Cu square] double left right arrow [Al][B-2]) and shows channels parallel to the a axis with a free diameter of about 2.3 angstrom. The squarate dianion, [C4O4](2-), is acting as a mu(6)-ligand, in this case. 2005-108 Solovyov, LA Astachov, AM Molokeev, MS Vasiliev, AD Powder diffraction crystal structure analysis using derivative difference minimization: example of the potassium salt of 1-(tetrazol-5-yl)-2-nitroguanidine ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 435-442. The crystal structure of the potassium salt of 1-( tetrazol- 5- yl)-2- nitroguanidine [K(C2H3N8O2)] was solved and refined from X-ray powder diffraction data by applying the derivative difference minimization (DDM) method. The compound is of interest as an energetic substance. The structure model was found from a Patterson search. The reflection intensities for the Patterson synthesis were derived from the powder profile by applying a newly developed DDM-based profile decomposition procedure. The use of the DDM method allowed successful location and unconstrained refinement of all the atomic positions, including those of three independent H atoms. The advantages of DDM in terms of the precision and reproducibility of the structural parameters are discussed in comparison to Rietveld refinement results. The failure to refine the H-atom positions by the Rietveld method was attributed to systematic errors associated with the background modelling, which are avoided by DDM. 2005-109 El-Himri, A Nunez, P Sapina, F Beltran, A Freeze-dried precursor-based synthesis of new polymetallic oxynitrides, V1-u-zCruMoz(OxNy),V1-u-zCruWz(OxNy), Cr1-u-zMouWz(OxNy) (u, z=0.2, 0.33, 0.4, 0.6, u plus z < 1), and VzCrzMozWz(OxNy) (z=0.25) JOURNAL OF ALLOYS AND COMPOUNDS 398, 2005, 289-295. Interstitial polymetallic oxynitrides in the solid solution series V1-u-zCruMoz(OxNy), V1-u-zCruWz(OxNy) and Cr1-u-zMouWz(OxNy) (u, z=0.2, 0.33, 0.4, 0.6, u+z < 1), as well as the tetrametallic VzCrzMozWz(OxNy) (z=0.25) composition, can be obtained by ammonolysis of precursors resulting from the freeze-drying of aqueous solutions of the simple metal salts NH4VO3, (NH4)(2)CrO4, (NH4)(6)Mo(7)O(24)center dot 4H(2)O and (NH4)(6)W(12)O(39)center dot 18H(2)O. A study of the influence of the preparative variables on the outcomes of this procedure is presented. Compounds in the V1-u-zCruMoz(OxNy) series have been prepared as single phases by direct ammonolysis of the respective freeze-dried precursors during 2h at 1173 K, followed by fast cooling of the samples. In contrast, the preparation of compounds in both the V1-u-zCruWz(OxNy) and the Cr1-u-zMouWz(OxNy) series requires the intermediate formation of crystalline precursors. These last compounds result from thermal treatment in air at 973 K, during 12 h, of the corresponding freeze-dried powders. Then, they were subjected to ammonolysis, during 2 h, at 1123 K (V containing series) or 1173 K (Mo containing series), followed by slow cooling of the samples. The tetrametallic VzCrzMozWz(OxNy) compound also has been prepared as single phase by ammonolysis of the crystalline intermediate at 1073 K, during 2 h, followed by slow cooling. All the compounds in these series have the rock-salt crystal structure, in which the metal atoms are in a face-centred cubic arrangement, with non-metal atoms occupying octahedral interstitial positions. The materials have been characterized by X-ray powder diffraction, elemental analysis, thermogravimetric analysis under oxygen flow and scanning electron microscopy. 2005-110 Hildebrandt, L Dinnebier, R Jansen, M Crystal structure and ionic conductivity of cesium trifluoromethyl sulfonate, CSSO3CF3 ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 1660-1666. The crystal structures of the room and the high temperature modifications of cesium trifluoromethyl sulfonate were solved from high resolution X-ray powder diffraction data. At room temperature, alpha-CsSO3CF3 crystallizes in the monoclinic space group P2(1) with lattice parameters a = 9.7406(2) angstrom, b = 6.1640(1) angstrom, c = 5.4798(1) angstrom, and beta = 104.998(1)degrees; Z = 2. At temperatures above T = 380 K, a second order phase transformation towards a disordered C-centered orthorhombic phase in space group Cmcm occurs with lattice parameters at T = 492 K of a = 5.5074(3) angstrom, b = 19.4346(14) angstrom, and c = 6.2978(4) angstrom; Z = 4. Within the crystal structures, the triflate anions are arranged in double layers with the apolar CF3-groups pointing towards each other. The cesium ions are located between the SO3-groups. CsSO3CF3 shows a specific ion conductivity ranging from sigma = 1.06 center dot 10(-8) Scm(-1) at T = 393 K to sigma = 5.18 center dot 10(-4) Scm(-1) at T = 519 K. 2005-111 Khalyavin, DD Senos, AMR Mantas, PQ Crystal structure of La4Mg3W3O18 layered oxide JOURNAL OF PHYSICS-CONDENSED MATTER 17, 2005, 2585-2595. The crystal structure of A-site deficient La4M93W3O18 perovskite has been solved by x-ray powder diffraction in combination with group theoretical analysis. Above 700 K, the crystal structure is orthorhombic (space group Ibam; 2a(p) x 4a(p) x 2a(p) type superstructure) and presents a sequence of [LaO]-[Mg1/2W1/2O2]-[La1/3O]'-[Mg1/2W1/2O2]-[LaO]-[Mg1/2W1/2O2]-[La1/3O] "-[Mg1/2W1/2O2] layers stacked along the b axis. The lanthanum ions and the vacancies in the [La1/3O]' and [La1/3O]" layers are ordered and form rows along the c axis. A half-period shift along the a direction between these layers leads to a quadrupling of the primitive perovskite unit cell in the b direction. The ordering of the vacancies in the lanthanum poor layers is connected with the ionic ordering between Mg2+ and W6+ in the neighbouring [Mg1/2W1/2O2] blocks. Around 700 K, due to an anti-phase rotation of the octahedra, a continuous phase transition mediated by the Gamma(2)(+) irreducible representation from orthorhombic (Ibam, a(0)b(0)c(0)) to monoclinic (C2/m, a(0)b(0)c(-)) symmetry takes place. 2005-112 Li, DY O'Connor, B van Riessen, A Mackinnon, C Low, IM Structural determination of high T-c superconductor (Bi, Pb)(2)Sr2Ca2Cu3Ox(2223) phase with powder diffraction data SUPERCONDUCTOR SCIENCE & TECHNOLOGY 18, 2005, 373-380. The (Bi, Pb)(2)SrCa2Cu3Ox (2223) phase is regarded as the one of the most technologically significant high T-C phases in the Bi-Sr-Ca-Cu-O system. However, its structure has not been fully described so far. The definitive structure model of 2223 has been determined in this study by direct methods and Q-peak analysis of difference Fourier maps using synchrotron radiation data. Successive least squares refinement of the model with the preferred A2aa space group was carried out by Rietveld procedures with neutron diffraction data. Anomalies were not observed for interatomic distances (bonded and non-bonded atoms), bond angles and isotropic temperature parameters. Two categories of copper atoms were clearly identified: (i) square coordinated to four oxygen atoms and (ii) pyramids with a fifth oxygen atom. The valence states of two Cu atoms have been estimated using bond valence calculations, as employed by Brown for YBCO. There is no direct bridging between the Cu squares and pyramids. The Bi3+ cations are coordinated by three oxygen atoms and form a single chain [BiO2](n)(n-) along the a axis, which is the first report of this feature for the 2223 structure. 2005-113 Vensky, S Kienle, L Dinnebier, RE Masadeh, AS Billinge, SJL Jansen, M The real structure of Na3BiO4 by electron microscopy, HR-XRD and PDF analysis ZEITSCHRIFT FUR KRISTALLOGRAPHIE 220, 2005, 231-244. The real structure of a new crystalline high temperature phase, metastable at room temperature, in the system sodium - bismuth - oxygen, beta-Na3BiO4, was determinated using high resolution X-ray powder diffraction, pair distribution function analysis, and high resolution transmission electron microscopy. beta-Na3BiO4 was synthesized by anodic oxidation of bismuth(III)-oxide in a sodium hydroxide - lithium hydroxide melt. The average crystal structure of beta-Na3BiO4 at ambient conditions (R(3) over bar m, a = 3.32141(9) angstrom, c = 16.4852(5) angstrom) is structurally related to alpha-NaFeO2 With metal layers almost statistically occupied in a Na: Bi ratio of 3: 1. Analysis of the long-range order on the bulk material by Rietveld refinement led to approximately Na: Bi ratios of 2: 1 and 4: 1, in consecutive metal layers, while a detailed analysis of the local order by means of the pair distribution function revealed the existence of almost pure sodium layers and mixed 1: 1 - sodium: bismuth layers. Complementary studies on single crystallites using high resolution transmission electron miscroscopy exhibited a complex domain structure with short-range ordered, partially ordered, and long-range ordered domains. 2005-114 Solovyov, LA Belousov, OV Dinnebier, RE Shmakov, AN Kirik, SD X-ray diffraction structure analysis of MCM-48 mesoporous silica JOURNAL OF PHYSICAL CHEMISTRY B 109, 2005, 3233-3237. The structure of MCM-48 mesoporous silicate materials has been fully characterized from X-ray diffraction data by applying recently developed methods of mesostructure analysis and full-profile refinement. The pore wall thickness of both as-made and calcined MCM-48 was determined with high precision to be 8.0(1) Angstrom. No regular variations of the wall thickness were detected, but its density was found to be ca. 10% higher in the low-curvature regions. The surfactant density in the pores was assessed around 0.6-0.7 g/cm(3) and was found to have a distinct minimum in the pore center similar to that detected previously in MCM-41. A new extended model function of the density distribution in MCM-48 is proposed on the basis of the structural features that were revealed. 2005-115 Dinnebier, RE Vensky, S Jansen, M Hanson, JC Crystal structures and topological aspects of the high-temperature phases and decomposition products of the alkali-metal oxalates M-2[C2O4] (M = K, Rb, Cs) CHEMISTRY-A EUROPEAN JOURNAL 11, 2005, 1119-1129. The high-temperature phases of the alkali-metal oxalates M-2[C2O4] (M=K, Rb, Cs), and their decomposition products M-2[CO3] (M=K, Rb, Cs), were investigated by fast, angle-dispersive X-ray powder diffraction with an image-plate detector, and also by simultaneous differential thermal analysis (DTA)/thermogravimetric analysis (TGA)/mass spectrometry (MS) and differential scanning calorimetry (DSC) techniques. The following phases, in order of decreasing temperature, were observed and crystallographically characterized (an asterisk denotes a previously unknown modification): *alpha-K-2[C2O4], *alpha-Rb-2[C2O4], *alpha-Cs-2[C2O4], alpha-K-2[CO3], *alpha-Rb-2[CO3], and *alpha-Cs-2[CO3] in space group P6(3)/mmc; *beta-Rb-2[C2O4], *beta-Cs-2[C2O4], *beta-Rb-2[CO3], and *beta-Cs-2[CO3] in Pnma; gamma-Rb-2[C2O4], gamma-Cs[C2O4], gamma-Rb-2[CO3], and gamma-Cs-2[CO3] in P2(1)/c; and delta-K-2[C2O4] and delta-Rb-2[C2O4] in Pbam. With respect to the centers of gravity of the oxalate and carbonate anions, respectively, the crystal structures of all known alkali-metal oxalates and carbonates belong to the AlB2 family, and adopt either the AlB2 or the Ni2In arrangement depending on the size of the cation and the temperature. Despite the different sizes and constitutions of the carbonate and oxalate anions, the high-temperature phases of the alkali-metal carbonates M-2[CO3] (M=K, Rb, Cs), exhibit the same sequence of basic structures as the corresponding alkali-metal oxalates. The topological aspects and order-disorder phenomena at elevated temperature are discussed. 2005-116 Ahlert, S Dinnebier, R Jansen, M The crystal structures of the high-temperature phases of Ag4Mn3O8 ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 90-98. Two endothermic, reversible structural phase transitions of first order have been observed in Ag4Mn3O8 by means of in-situ powder diffraction and by differential scanning calorimetry. At a temperature of T = 477 K, Ag4Mn3O8 undergoes a structural phase transition from the room temperature phase in space group P3(1)21 to a phase in space group R32, and at T = 689 K a second phase transition to a structure in space group P4(3)32 occurs. Whilst the Mn3O8 framework does not change significantly upon heating, rearrangements of the silver atoms, located in the cavities of the framework, were found to be the driving force behind the transitions. The structural chances with increasing temperature proceed along a path of minimal group-supergroup relations between the respective space groups. 2005-117 Pan, ZG Cheung, EY Harris, KDM Constable, EC Housecroft, CE A case study in direct-space structure determination from powder X-ray diffraction data: Finding the hydrate structure of an organic molecule with significant conformational flexibility CRYSTAL GROWTH & DESIGN 5, 2005, 2084-2090. The structure of the monohydrate crystalline phase of 3,5-bis((3,4,5-trimethoxybenzyl)oxy)benzyl alcohol has been determined directly from powder X-ray diffraction data using the direct-space genetic algorithm technique for structure solution followed by Rietveld refinement. This work raises several issues of a general nature concerning the assessment of results obtained in the structure determination of organic molecular solids from powder X-ray diffraction data and serves as a case study that may find wider relevance in this field. 2005-118 Okudera, H Dinnebier, RE Simon, A The crystal structure of gamma-P-4, a low temperature modification of white phosphorus ZEITSCHRIFT FUR KRISTALLOGRAPHIE 220, 2005, 259-264. The crystal structure of gamma-P-4, one of three modifications hitherto reported on white phosphorus, was determined from X-ray powder diffraction data collected at T = 123 K on a Guinier-Simon camera equipped with a cold gas blower and an image plate detector. Crystallographic data at T = 123 K are: space group C2/m, a = 9.1709(5) angstrom, b 8.3385(5) angstrom, c = 5.4336(2) angstrom, and beta = 90.311(3)degrees, V 415.51(6) angstrom(3), Z = 4. The crystal structure Of gamma-P4 was solved by the method of simulated annealing. The subsequent Rietveld refinement in the range 12 degrees < 20 < 92 degrees employing rigid-body constraints on the P-4 molecule converged at R-p = 3.8, wR(p) = 5.0, and R-F(2) = 14.0%. The asymmetric unit Of gamma-P-4 contains three P atoms; two P atoms in a molecule are related by a mirror plane which bisects the molecule. The centers of gravity of these P-4 molecules show a distorted body-centered cubic arrangement. The four apices of the P-4 tetrahedron point to the largest possible voids formed by neighbor molecules. The difference to the crystal structures of SiF4 and GeF4 with an exact bcc arrangement of tetrahedral molecules is discussed as well as, in terms of layer stackings, the similarity of the structures of gamma- and beta-P-4. 2005-119 Ryabova, SY Rastorgueva, NA Sonneveld, EJ Peschar, R Schenk, H Tafeenko, VA Aslanov, LA Chernyshev, VV Structural characterization of [1,4]diazepino[6,5-b]indoles by powder diffraction ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 192-199. As part of a systematic structural study of potentially pharmacologically active [1,4] diazepino[6,5-b] indoles, the crystal structures of nine compounds have been determined from laboratory powder diffraction data. The investigated compounds are: 2-oxo-1-(4-nitrophenyl)- 1,2,3,6-tetrahydro[ 1,4] diazepino[ 6,5-b] indole-4-oxide, C17H12N4O4 (1a); 2-oxo- 1-phenyl-1,2,3,6-tetrahydro[1,4] diazepino[6,5-b] indole-4-oxide, C17H13N3O2 (1b); 2-oxo-1-(4-ethoxyphenyl)-1,2,3,6-tetrahydro[ 1,4] diazepino[6,5-b] indole-4-oxide, C19H17N3O3( 1c); 2-oxo- 1-(4-chlorophenyl)- 1,2,3,6- tetrahydro[ 1,4] diazepino[ 6,5-b] indole-4-oxide, C17H12N3O2Cl (1d); 2-oxo-1-(4-cyanophenyl)- 1,2,3,6-tetrahydro[1,4] diazepino[6,5-b] indole-4-oxide, C18H12N4O2 (1e); 6-methyl-2-oxo-1-phenyl-1,2,3,6-tetrahydro[ 1,4] diazepino[6,5-b] indole-4-oxide, C18H15N3O2 (1f); 2-formyl-3-[N'-(omega-chloracetyl)- N'-(4-nitrophenyl)] aminoindole, C17H12N3O4Cl (2a); 2-formyl-3-[N'-(omega-chloracetyl)N'-( 4-nitrophenyl)] aminoindole solvate with toluene (2: 1), C17H12N3O4Cl center dot 0.5C(7)H(8) (2as); 2-formyl-3-[N'-(omega-chloracetyl)N'-( 4-cyanophenyl)] aminoindole, C18H12N3O2Cl (2e). Compounds ( 1a) -( 1f) crystallize in non-centrosymmetric triclinic, monoclinic and orthorhombic space groups. The three-dimensional structures of ( 1a) -( 1e) demonstrate identical intermolecular NH( indole) center dot center dot center dot O<--N hydrogen bonds, which form linear chains of connected molecules. A comparison of the crystal structures ( 2a), ( 2e) and ( 2as) shows that the solvent used in the re-crystallization of ( 2a) and ( 2e), which are intermediates in the synthesis of ( 1a) and ( 1e), affects the intermolecular hydrogen-bond formation and, as a result, leads to essentially different yields of the goal products. 2005-120 Stride, JA Determination of the low-temperature structure of hexamethylbenzene ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 200-206. The low-temperature structure of hexamethylbenzene has been determined from neutron powder diffraction data and found to differ from the room-temperature phase predominantly by a translation of molecular planes to a form a cubic close-packed type structure. By performing measurements as a function of temperature, the role of thermally induced agitation of the molecular units in the first-order phase transition is clearly demonstrated. 2005-121 Guillou, N Livage, C Chaigneau, J Ferey, G Structural investigation of the nickel 3-methylglutarate from powder diffraction demonstrating adaptability of the inorganic skeleton of MIL-77 POWDER DIFFRACTION 20, 2005, 288-293. Ni-20[(C6H8O4)(20)(H2O)(8)]center dot 33H(2)O, a new nickel(II) 3-methylglutarate, was prepared hydrothermally (180 degrees C, 48 h, autogenous pressure) from a 1: 1.5:2:180 mixture of nickel (II) sulphate hexahydrate, 3-methylglutaric acid, sodium hydroxide, and water. It crystallizes in the cubic system (space group P4(3)32, Z=1) with a = 16.8488(5) angstrom and V=4783.1(4) angstrom(3). Its structure was solved from conventional X-ray powder diffraction data. It presents a three-dimensional network of edge-sharing nickel octahedra, lined by deprotonated organic anions. This remarkable oxide network with corrugated 20-membered rings is constructed from homochiral helices. The rings intersect each other to generate large crossing channels full of water along [111]. 2005-122 Fossdal, A Brinks, HW Fichtner, M Hauback, BC Determination of the crystal structure of Mg(AlH4)(2)by combined X-ray and neutron diffraction JOURNAL OF ALLOYS AND COMPOUNDS 387, 2005, 47-51. The structure of magnesium alanate, Mg(AlH4)(2), has been examined in detail by combined powder synchrotron X-ray and neutron diffraction. The space group is confirmed to be P (3) over barm 1 with unit cell dimensions of a = 5.2084(3) Angstrom and c = 5.8392(5) Angstrom at 8 K, a = 5.20309(12) Angstrom and c = 5.8400(2) Angstrom at 111 K and a = 5.1949(2) Angstrom and c = 5.8537(2) Angstrom at 295 K. The structure consists of isolated and slightly distorted AlH4- tetrahedra that are connected via six-coordinated Mg atoms in a distorted octahedral geometry, resulting in a sheet-like structure along the crystallographic c-axis. The distortion of the AlH4- tetrahedra decreases with increasing temperature, whereas, the opposite is the case for the MgH6 octahedra. The Al-H distances are 1.606(10)-1.634(4) Angstrom, 1.602(10)-1.682(3) Angstrom and 1.561(12)-1.672(4) Angstrom at 8, 111 and 295 K, respectively. 2005-123 Brandel, V Clavier, N Dacheux, N Synthesis and characterization of uranium(IV) phosphate-hydrogenphosphate hydrate and cerium(IV) phosphate-hydrogenphosphate hydrate JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 1054-1063. A new uranium (IV) phosphate of proposed formula U-2(PO4)(2)(HPO4H2O)-H-., i.e. uranium phosphate-hydrogen phosphate hydrate (UPHPH), was synthesized in autoclave and/or in polytetrafluoroethylene closed containers at 150 degrees C by three ways: from uranium (IV) hydrochloric Solution and phosphoric acid, from uranium dioxide and phosphoric acid and by transformation Of the uranium hydrogenphosphate hydrate U(HPO4)(2)(.)nH(2)O. The new product appears similar to the previously published thorium phosphate-hydrogenphosphate hydrate Th-2(PO4)(2)(HPO4H2O)-H-. (TPHPH). From preliminary studies, it was found that UPHPH crystallizes in monoclinic system (a = 2.1148(7) nm, b = 0.6611(2) nm, c = 0.6990(3) nm, beta = 91.67(3)degrees and V = 0.9768(10) nm(3)). Heated under inert atmosphere, this compound is decomposed above 400 degrees C into uranium phosphate-triphosphate U-2(PO4)P3O10, uranium diphosphate alpha-UP2O7 and diuranium oxide phosphate U2O(PO4)(2). Crystallized cerium (IV) phosphate-hydrogenphosphate hydrate Ce-2(PO4)(2)(HPO4H2O)-H-. (CePHPH) was also synthesized from (NH4)(2)Ce(NO3)(6) and phosphoric acid Solutions by the same method (inonoclinic system: a = 2.1045(5) nm, b = 0.6561(2) nm, c = 0.6949(2) nm, beta = 91.98(1)degrees and V = 0.9588(9) nm(3)). When heating above 600 degrees C. cerium (IV) is reduced into Ce (III) and forms a mixture of CePO4 (monazite structure) and CeP3O9. 2005-124 Shpanchenko, RV Lapshina, OA Antipov, EV Hadermann, J Kaul, EE Geibel, C New lead vanadium phosphate with langbeinite-type structure: Pb1.5V2(PO4)(3) MATERIALS RESEARCH BULLETIN 40, 2005, 1569-1576. The new lead vanadium phosphate Pb1.5V2(PO4)(3) was synthesized by solid state reaction and characterized by X-ray powder diffraction, electron microscopy, and magnetic susceptibility measurements. The crystal structure of Pb1.5V2(PO4)(3) (a=9.78182(8) angstrom, S.G. P2(1)3, Z=4) was determined from X-ray powder diffraction data and belongs to the langbeinite-type structures. It is formed by corner-linked V3+O6 octahedra and tetrahedral phosphate groups resulting in a three-dimensional framework. The lead atoms are situated in the structure interstices and only partially occupy their positions. An electron microscopy study confirmed the structure solution. Magnetic susceptibility measurements revealed Curie-Weiss (CW) behavior for Pb1.5V2(PO4)(3) at high temperature whereas at around 14 K an abrupt increase on the susceptibility was observed. 2005-125 Redman-Furey, N Dicks, M Bigalow-Kern, A Cambron, RT Lubey, G Lester, C Vaughn, D Structural and analytical characterization of three hydrates and an anhydrate form of risedronate JOURNAL OF PHARMACEUTICAL SCIENCES 94, 2005, 893-911. Four hydration states are reported for Risedronate monosodium. A single-crystal X-ray structure determination is provided as proof of assignment for the monohydrate, hemi-pentahydrate, and variable hydrate forms. The structure provided for the anhydrate form was determined through simulating annealing calculations and subsequent Reitveld refinement of a high-quality X-ray powder diffraction patterns Favorable comparisons of experimentally obtained X-ray powder patterns are made to those generated from the single crystal data. Characteristic infrared, Raman, and NMR spectra are provided and discussed for each form as are thermal analysis profiles. In addition, photomicrographs are provided for each of the forms isolated for this study. The hemi-pentahydrate is demonstrated to be the equilibrium form at room temperature and 37 degrees C, in the presence of water. 2005-126 Karau, FW Schnick, W High-pressure synthesis and X-ray powder structure determination of the nitridophosphate BaP2N4 JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 135-141. The novel nitridophosphate BaP2N4 was obtained by means of high-pressure high-temperature synthesis utilizing the multianvil technique (8 GPa, 1400degreesC. The [PN2](-) network is isoelectronic with silica. The structure was solved from synchrotron powder data by a combination of direct methods and difference FOURIER synthesis and refined using the RIETVELD method (BaP2N4,Pa $$(3) over bar, Z= 12, a = 10.22992(2) Angstrom). BaP2N4 is isotypic with BaGa2S4, BaAl2S4 and the high-pressure phase of CaB2O4. The (31)p solid-state NMR yielded a single sharp resonance at 0.4ppm. 2005-127 Chemnitzer, R Auffermann, G Tobbens, DM Kniep, R (Sr2N)H: On the redox-intercalation of hydrogen into Sr2N ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 1813-1817 Strontium-nitride-hydride is obtained as brown-yellow single phase powder by reaction of strontium-subnitride (Sr2N) with hydrogen (200 bar, 620 K) and subsequent treatment under vacuum (10(-6) bar, 870 K). The structure determination was carried out by a combination of X-ray and neutron diffraction experiments on a deuterated sample. The elemental composition of the ternary compound was confirmed by means of chemical analyses. (Sr2N)D crystallizes in the space group R (3) over barm with a = 381.91(2) pm and c = 1887.61(2) pm. Strontium (Sr2+) in the crystal structure of (Sr2N)D is arranged with an only slightly distorted ccp-motif. Nitrogen (N3-) and deuterium (D-) occupy the octahedral voids of the Sr2+ matrix in an ordered manner resulting in an alternating sequence of layers (anti-alpha-NaFeO2-type structure). 2005-128 Argyriou, DN Radaelli, PG Milne, CJ Aliouane, N Chapon, LC Chemseddine, A Veira, J Cox, S Mathur, ND Midgley, PA Crystal structure of the superconducting layered cobaltate NaxCoO2 center dot yD(2)O JOURNAL OF PHYSICS-CONDENSED MATTER 17, 2005, 3293-3304. We have used electron diffraction and neutron powder diffraction to elucidate the structural properties of superconducting Na(x)CoO(2)(.)yD(2)O over a wide compositional range. Our measurements show that superconducting samples exhibit a number of supercells ranging from (1)/(3)a* to (1)/(15)a*, but the predominant modulation, observed also in the neutron data, is a double hexagonal cell with dimensions 2a x 2a x c. Rielveld analysis reveals that D2O is inserted between CoO2 sheets to form a layered network of NaO6 triangular prisms. Our model removes the need to invoke a 5 K superconducting point compound and suggests that a solid solution of Na is possible within a relatively constant amount of water y. 2005-129 Vicente, J Arcas, A Fernandez-Hernandez, JM Sironi, A Masciocchi, N An unprecedented process involving normal and redox transmetallation reactions between Hg and Pt affording the unexpected K[Pt-2{CH2C(O)Me}(6)(mu-Cl)(3)] complex: the key role of X-ray powder diffraction in unravelling its nature and structure CHEMICAL COMMUNICATIONS iss 10, 2005, 1267-1269. Hg{CH2C(O) Me}(2)] reacts with K[PtCl3(CH2LCH2)] (2 : 1 molar ratio) to give K[Pt-2{CH2C(O) Me}(6)(mu- Cl)(3)] ( 1); the intermediate [Pt{CH2C(O) Me} Cl-2(CH2=CH2)](-) has been detected in solution and isolated as a Me4N+ salt; the process occurs through successive normal and redox transmetallation reactions and an ab initio X-ray powder diffraction study of 1 has proven to be essential to establish its nature. 2005-130 Wu, L Chen, XL Li, XZ Dai, L Xu, YP Zhao, M Synthesis and ab initio X-ray powder diffraction structure of the new alkali and alkali earth metal borate NaCa(BO3) ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS61, 2005, I32-I34 A sodium calcium borate, NaCaBO3, has been synthesized by the solid-state reaction method and the structure solved from X-ray powder diffraction data. The compound crystallizes in space group Pmmn and has a desired structure type containing isolated planar BO33- anions. Mixed occupancy is found to exist in the Ca site, with partial replacement by Na. One Ca/Na mixed atom and one Na atom are at sites with mm2 symmetry, and a second Ca/Na mixed atom, an Na atom, two B and two O atoms are on mirror planes. 2005-131 Dova, E Peschar, R Takata, M Nishibori, E Schenk, H Stassen, AF Haasnoot, JG Low-spin state structure of [Fe(chloroethyltetrazole)(6)] (BF4)(2) obtained from synchrotron powder diffraction data CHEMISTRY-A EUROPEAN JOURNAL 11, 2005, 5855-5865. The complex [Fe(teec)(6)]-(BF4)(2) (teec = chloroethyltetrazole) shows a two-step complete spin-crossover transition in the temperature range 300-90 K. Time-resolved synchrotron powder diffraction experiments have been carried out in this temperature range, and crystal. structure models have been obtained from the powder patterns by using the parallel tempering technique. Of these models, the low-spin state structure at 90 K has been refined completely with Rietveld refinement. Its structural characteristics are discussed in relation to the high-spin state model and other spin-crossover compounds. The complex shows a remarkable anisotropic unit-cell parameter contraction that is dependent on the applied cooling rate. In addition, the possible important implications for the interpretation of spin-crossover behavior in terms of structural changes are discussed. 2005-132 Liu, XH Wankeu, MA Lucken, H Dronskowski, R A novel method for synthesizing crystalline copper carbodiimide, CuNCN. Structure determination by X-ray rietveld refinement ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 60, 2005, 593-596. Well-crystallized copper carbodiimide, CuNCN, was synthesized by the slow oxidation of a copper(l) cyanamide precursor under aqueous conditions. The X-ray powder data evidence the orthorhombic system and space group Cmcm with a = 2.9921(1), b = 6.1782(1), c = 9.4003(2) angstrom, V = 173.769(5) angstrom(3) and Z = 4. There is a strongly distorted octahedral Cu2+ coordination reflecting a typical first-order Jahn-Teller effect, with interatomic distances of 4 x Cu-N = 2.001(2) angstrom and 2 x Cu-N = 2.613(3) angstrom; the NCN2- unit adopts the carbodiimide shape with C-N = 1.227(4) A. Despite the formal d(9) electron count of Cu2+, CuNCN exhibits a small temperature-independent paramagnetism and is likely to be a metallic conductor. 2005-133 Xu, HW Navrotsky, A Nyman, M Nenoff, TM Thermochemistry of framework titanosilicate A(2)TiSi(6)O(15) (A = K, Rb, Cs) JOURNAL OF THE AMERICAN CERAMIC SOCIETY 88, 2005, 1819-1825. A new family of framework titanosilicates, A(2)TiSi(6)O(15) (A = K, Rb, Cs) (space group Cc), has recently been synthesized using the hydrothermal method. This group of phases can potentially be utilized for storage of radioactive elements, particularly Cs-137, due to its high stability under electron radiation and chemical leaching. Here, we report the syntheses and structures of two intermediate members in the series: KRbTiSi6O15 and RbCsTiSi6O15. Rietveld analysis of powder synchrotron X-ray diffraction data reveals that they adopt the same framework topology as the end-members, with no apparent Rb/K or Rb/Cs ordering. To study energetics of the solid solution series, high-temperature drop-solution calorimetry using molten 2PbO center dot B2O3 as the solvent at 975 K has been performed for the end-members and intermediate phases. As the size of the alkali cation increases, the measured enthalpies of formation from the constituent oxides (Delta H-f,ox(0)) and from the elements (Delta H-f,el(0)) become more exothermic, suggesting that this framework structure favors the cation in the sequence Cs+, Rb+, and K+. This trend is consistent with the higher melting temperatures of A(2)TiSi(6)O(15) phases with increase in the alkali cation size. 2005-134 Dikarev, EV Li, B Chernyshev, VV Shpanchenko, RV Petrukhina, MA Coordination polymers formed in solution and in solvent-free environment. Structural transformation due to interstitial solvent removal revealed by X-ray powder diffraction CHEMICAL COMMUNICATIONS iss 26, 2005, 3274-3276. The crystal-to-powder transformation induced by solvent removal has been examined through a direct comparison of the structures of the solvated and the unsolvated coordination products determined by single crystal and powder X-ray diffraction, respectively. 2005-135 Shrivastava, OP Kumar, N Sharma, IB Synthesis, characterization and structural refinement of polycrystalline uranium substituted zirconolite JOURNAL OF MATERIALS SCIENCE 40, 2005, 2945-2950. Ceramic precursors of Zirconolite (CaZrTi2O7) family have a remarkable property of substitution on Zr4+ cationic sites. This makes them potential material for nuclear waste management in 'synroc' technology. In order to simulate the mechanism of partial substitution of zirconium by tetravalent actinides, a solid phase of composition CaZr0.95U0.05Ti2O7 has been synthesized through ceramic route by taking calculated quantities of oxides of Ca, Ti and nitrates of uranium and zirconium respectively. Solid state synthesis has been carried out by repeated pelletizing and sintering the finely powdered oxide mixture in a muffle furnace at 1050 degrees C. The polycrystalline solid phase has been characterized by its typical powder diffraction pattern. Step analysis data has been used for ab initio calculation of structural parameters. The SEM and EDAX analysis also confirm that zirconolite acts as a host material for uranium. The powder diffraction data of 3500 points between 2 theta = 10 - 80 degrees has been analysed by GSAS ( general structure analysis system) software to obtain the best fit of the observed data points. The uranium substituted zirconolite crystallizes in monoclinic symmetry with space group C2/c (# 15). The following unit cell parameters have been calculated: a = 12.4883( 15), b = 7.2448( 5), c = 11.3973( 10) and beta = 100.615( 9)degrees. The calculated and observed values of the intensities, lattice parameters and density measurement shows good agreement. The Rietveld analysis and GSAS based calculations for bond distance Ti-O, Ca-O, Zr-O, and O-M-O bond angles have been made. The structure was refined to satisfactory completion. The and Rp and Rwp are found to be 7.48 and 9.74 % respectively. 2005-136 ??? Zhu, ZM Andelman, T Yin, M Chen, TL Ehrlich, SN O'Brien, SP Osgood, RM Synchrotron x-ray scattering of ZnO nanorods: Periodic ordering and lattice size JOURNAL OF MATERIALS RESEARCH 20, 2005, 1033-1041. We demonstrate that synchrotron x-ray powder diffraction (XRD) is a powerful technique for Studying the structure and self-organization of zinc-oxide nanostructures. Zinc-oxide nanorods were prepared by a solution-growth method that resulted ill uniform nanorods with 2-nm diameter and lengths in the range 10-50 nm. These nanorods were structurally characterized by a combination of small-angle and wide-angle synchrotron XRD and transmission electron microscopy (TEM). Small-angle XRD and TEM were used to investigate nanorod self-assembly and the influence of surfactant/precursor ratio oil self-assembly. Wide-angle XRD was used to study the evolution of nanorod growth as a function of synthesis time and surfactant/precursor ratio. 2005-137 Orlova, MP Kitaev, DB Spiridonova, ML Zubkova, NV Kabalov, YK Orlova, AI Structure refinement of cadmium cerium(IV) phosphate Cd0.5Ce2(PO4)(3) CRYSTALLOGRAPHY REPORTS 50, 2005, 918-922. Cadmium cerium orthophosphate Cd0.5Ce2(PO4)(3) is synthesized by precipitation from aqueous solutions. The structure refinement from powder X-ray diffraction data is preceded by the sample preparation and structure solution. The refinement is carried out by the Rietveld method (ADP-2 diffractometer, Cu-K alpha radiation, Ni filter, 15 degrees < 2 theta < 120 degrees, 2 theta-scan step 0.02 degrees, counting time 10 s per step). All calculations are carried out using the WYRIET program (version 3.3) within the sp. gr. P2(1)/n. The structure is refined with anisotropic displacement parameters for cations and isotropic displacement parameters for oxygen atoms. 2005-138 Tobbens, DM Kahlenberg, V Kaindl, R Characterization and ab initio XRPD structure determination of a novel silicate with vierer single chains: The crystal structure of NaYSi2O6 INORGANIC CHEMISTRY 44, 2005, 9554-9560. The crystal structure of a sodium yttrium silicate with composition NaYSi2O6 has been determined from laboratory X-ray powder diffraction data by simulated annealing, and has been subsequently refined with the Rietveld technique. The compound is monoclinic with space group P2(1)/c and unit cell parameters of a = 5.40787(2) angstrom, b = 13.69784(5) A, c = 7.58431(3) angstrom, and beta = 109.9140(3)degrees at 23.5 degrees C (Z = 4). The structure was found to be a single-chain silicate with a chain periodicity of four. The two symmetry dependent [Si4O12] chains in the unit cell are parallel to c. A prominent feature is the strong folding of the crankshaft-like chains within the b,c-plane resulting in intrachain Si-Si-Si angles close to 90 degrees. The coordination of the Y3+ ions by O2- is 7-fold in the form of slightly irregular pentagonal bipyramids, with oxygen atoms from four different chains contributing to the coordination polyhedron. Na+ ions are irregularly coordinated by 10 oxygens from two neighboring chains. No disorder of Na+ and Y3+ between the two nontetrahedral cation sites could be observed. Furthermore, micro-Raman spectra have been obtained from the polycrystalline material. 2005-139 Parfitt, DC Keen, DA Hull, S Crichton, WA Mezouar, M Wilson, M Madden, PA High-pressure forms of lithium sulphate: Structural determination and computer simulation PHYSICAL REVIEW B 72, 2005, 054121. Powder x-ray diffraction has been performed on lithium sulphate, Li2SO4, in the temperature range 300 to 1000 K and at pressures up to 7.5 GPa. The ambient pressure beta phase appears stable up to 3 GPa, whereupon a slow transformation begins into a new phase, delta-Li2SO4. This phase is characterized by broad, very low intensity Bragg peaks. Above 7 GPa and with slight heating, another phase, epsilon-Li2SO4, is formed which shows sharp Bragg peaks. Rietveld refinement of the structure of the epsilon phase has shown it to be isostructural to the high-temperature phase III of Na2SO4. Molecular dynamics simulations of the epsilon phase using an established potential indicate disordering of the lithium ions and rotations of the sulphate groups at high temperature, but not at a level approaching the extreme disordering shown in the superionic alpha form of Li2SO4. 2005-140 Romer, SR Schnick, W Synthesis and crystal structure determination by X-ray powder diffraction of nickel tetrametaphosphimate octahydrate Ni-2(PO2NH)(4)center dot 8 H2O ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 631, 2005, 1749-1750. Ni(PO2NH)(4) center dot 8H(2)O is isotypic with M-2(PO2NH)(4) center dot 8 H2O (M = Mg, Mn, Co, Zn) and crystallizes in the space group P2(1)/c, Z = 2. with a = 641.25(l), b = 1041.42(l), c 1278.18(2) pm and beta = 104.243(l)degrees. The structure is composed of Ni2+ and (PO2NH)(4)(4-) ions as well as crystal water molecules. The P4N4 rings of the (PO2NH)(4)(4-) ions exhibit a slightly distorted chair-2 conformation, which has been described by torsion angles, displacement asymmetry parameters and Puckering parameters. The tetrametaphosphimate anions are connected forming layers. These layers are linked solely by hydrogen bonds, forming a three-dimensional network. 2005-141 Brodski, V Peschar, R Schenk, H Brinkmann, A Bloemberg, TG van Eck, ERH Kentgens, APM Structural analysis of a melaminium polyphosphate from X-ray powder diffraction and solid-state NMR data JOURNAL OF PHYSICAL CHEMISTRY B 109, 2005, 13529-13537. The crystal structure of the environmentally friendly flame retardant melaminium polyphosphate (MPoly) (2,4,6-triamino-1,3,5-triazinium-PO3)(n) was determined by a direct-space global optimization technique from X-ray powder diffraction data. Solid-state NMR was used to corroborate the proposed hydrogen-bonding model and to determine the average degree of polymerization (n > 100). An analysis of the crystal structure of MPoly reveals aspects of molecular geometry and packing that are characteristic for melamine-containing compounds and polyphosphate salts. A comparison of MPoly with the crystal structures of its precursors melaminium orthophosphate (MP) and melaminium dihydrogenpyrophosphate (MPy) provides insight in the mechanism of the endothermic dehydration processes that takes place in the reaction path MP -> MPy -> MPoly. Solid-state NMR characterization of various samples of the same batch showed inhomogeneities in the MPoly composition. Various quantities of orthophosphates were found, which cannot be assigned to be MP. 2005-142 Hoyos, D Paillaud, JL Simon-Masseron, A Guth, JL Synthesis, characterization and structure determination of a three-dimensional hydrated potassium zinc divanadate: K[Zn2.5V2O7(OH)2]center dot H2O SOLID STATE SCIENCES 7, 2005, 616-621. K[Zn2.5V2O7(OH)(2)]center dot H2O was obtained by hydrothermal synthesis at 170 degrees C from a gel with the molar composition 1 V2O5; 1 ZnCl2; 4 KOH; 228 H2O. The solid crystallizes in the orthorhombic system, with the space group Pnnm (58) and with the unit-cell parameters a = 14.5493(12) angstrom, b = 10.1685(9) angstrom, c = 6.0668(5) angstrom. The structure was determined from the powder XRD pattern by an "ab initio" method using the EXPO software and refined with the GSAS Rietveld refinement software. The structure can be described as formed from an interrupted and lacunary oxohydroxo zinc layers bridged by divanadate into a three-dimensional framework. The potassium cations and the water molecules occupy the channels between the bridged layers. The thermal stability, studied with the use of TGA and XRD, shows that the compound remains crystalline during the dehydration which occurs between room temperature and 210 degrees C. 2005-143 Shankland, K Kennedy, AR David, WIF Polymorphism in tetra-aryl biphenyl diamine hole transport materials: resolving the conflicting literature on N, N '-diphenyl-N, N '-bis(3,3'-methylphenyl)-1(1,1 '-biphenyl)1-4,4 '-diamine by high-resolution powder diffraction JOURNAL OF MATERIALS CHEMISTRY 15, 2005, 4838-4844. The existence of a second polymorphic form of the hole transport material N,N'-diphenyl-N,N'-bis(3,3'-methylphenyl)-[(1, 1'-biphenyl)]-4,4'-diamine has been confirmed using both Pawley and Rietveld refinement of structural information against high-resolution synchrotron X-ray powder diffraction data. 2005-144 Mellot-Draznieks, C Serre, C Surble, S Audebrand, N Ferey, G Very large swelling in hybrid frameworks: A combined computational and powder diffraction study JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127, 2005, 16273-16278. Using a combination of simulations and powder diffraction, we report here the study of the very large swelling of a three-dimensional nanoporous iron(III) carboxylate (MIL-88) which exhibits almost a reversible doubling (similar to 85%) of its cell volume while fully retaining its open-framework topology. The crystal structure of the open form of MIL-88 has been successfully refined and indicates that atomic displacements larger than 4 angstrom are observed when water or various alcohols are adsorbed in the porous structure, revealing an unusually flexible crystallized framework. X-ray thermodiffractometry shows that only a displacive transition occurs during the swelling phenomenon, ruling out any bond breaking. 2005-145 Ferey, G Mellot-Draznieks, C Serre, C Millange, F Dutour, J Surble, S Margiolaki, I A chromium terephthalate-based solid with unusually large pore volumes and surface area SCIENCE 309, 2005, 2040-2042. 2005-146 Warrender, SJ Wright, PA Zhou, W Lightfoot, P Camblor, MA Shin, CH Kim, DJ Hong, SB Structure of the novel large pore allosilicate TNU-7 MOLECULAR SIEVES: FROM BASIC RESEARCH TO INDUSTRIAL APPLICATIONS, PTS A AND B 158, 2005, 89-96. The Structure of a novel large pore gallosilicate zcolite, TNU-7, has been refined from X-ray powder diffraction data. The silicate framework is built Lip from two different types of layer which are shown by X-ray and electron diffraction to be arranged in a fully ordered way. This gives rise to 12-MR pores and asymmetric cation distributions. TNU-7 is prepared hydrothemally over a very narrow compositional range and only in the presence of Ga. Other zeolitic phases crystallise at lower and higher Ga contents confirming the unique structure-directing ability of this element. The location of ion exchanged Cs+ and Sr2+ cations in TNU-7 has been Studied by high resolution X-ray powder diffraction. Warrender, SJ Wright, PA Zhou, WZ Lightfoot, P Camblor, MA Shin, CH Kim, DJ Hong, SB TNU-7: A large-pore gallosilicate zeolite constructed of strictly alternating MOR and MAZ layers CHEMISTRY OF MATERIALS 17, 2005, 1272. The structure solution of TNU-7 (Taejon National University number 7), a large-pore gallosilicate zeolite constructed of strictly alternating MOR and MAZ layers, is presented. This "boundary phase" zeolite was synthesized without recourse to organic additives in a crystallization field surrounded by those of the structurally related MAZ and MOR zeolites. 2005-147 Snedden, A Charkin, DO Dolgikh, VA Lightfoot, P Crystal structure of the 'mixed-layer' Aurivillius phase Bi5TiNbWO15 JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 180-184. The crystal structure of the Aurivillius phase Bi5TiNbWO15 has been analyzed in detail using powder X-ray and neutron diffraction. The structure can be described as a regular intergrowth of alternating single and double perovskite-like layers sandwiched between fluorite-like bismuth oxide layers, such that the layer sequence is ... [WO4]-[Bi2O2]-[BiTiNbO7]-[Bi2O2] .... There is complete ordering of tungsten within the B sites of the single perovskite layer, so that the structure can be described as a direct intergrowth of the 'component' Aurivillius phases B2WO6 and Bi3TiNbO9. At 25degreesC the structure adopts the polar orthorhombic space group 12cm, a = 5.4231(2) Angstrom, b = 5.4027(2) Angstrom, c = 41.744(1)Angstrom. 2005-148 Jacob, DS Makhluf, S Brukental, I Lavi, R Solovyov, LA Felner, I Nowik, I Persky, R Gottlieb, HE Gedanken, A Sonochemical synthesis and characterization of Ni(C4H6N2)(6)(PF6)(2), Fe(C4H6N2)(6)(BF4)(2), and Ni(C4H6N2)(6)(BF4)(2) in 1-butyl-3-methylimidazole with hexafluorophosphate and tetrafluoroborate EUROPEAN JOURNAL OF INORGANIC CHEMISTRY iss 13, 2005, 2669-2677. This paper reports on the inorganic sonochemical synthesis of crystalline Ni(C4H6N2)(6)(PF6)(2), Fe(C4H6N2)(6)(BF4)(2), and Ni(C4H6N2)(6)(BF4)(2) in the ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate (BMI)(+)(PF6)(-) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMI)(+)(BF4)(-). The structures of the compounds were determined and refined by using powder X-ray diffraction methods. The salts crystallize in the trigonal P (3) over bar space group. IR, Raman and F-19 NMR spectroscopic studies confirm that the PF6- and BF4- anions are not bonded to the metal cations. Magnetic measurements reveal the paramagnetic nature of the complexes. Mossbauer investigations show that the iron atom in Fe(C4H6N2)(6)(BF4)(2) is in the oxidation +2 state. The broad EPR signals, which reflect the octahedral symmetry of the nickel complexes, were measured for Ni(C4H6N2)(6)(PF6)(2) and Ni(C4H6N2)(6)(BF4)(2). 2005-149 Body, M Silly, G Legein, C Buzare, JY Calvayrac, F Blaha, P Structural investigations of beta-CaAlF5 by coupling powder XRD, NMR, EPR and spectroscopic parameter calculations JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 3655-3661. beta-CaAlF5 was synthesized by solid-state reaction. The precise structure was refined from X-ray powder diffraction data in the monoclinic space group P2(1)/c with lattice constants a = 5.3361 angstrom, b = 9.8298 angstrom, c = 7.3271 angstrom, and beta = 109.91 degrees (Z = 4). The structure exhibits isolated chains of AlF63- octahedra sharing opposite corners. F-19 and Al-27 solid state NMR spectra were recorded Using MAS and SATRAS techniques. An EPR spectrum was recorded for beta-CaAlF5:Cr3+. The experimental spectra were simulated in order to extract the NMR and EPR parameter values. Five fluorine sites and one low symmetry aluminium site were found in agreement with the refined structure. These parameters were calculated using empirical and ab-initio methods. The agreement obtained between the calculated F-19 chemical shift values, Al-27 quadrupolar parameters, Cr3+ EPR fine structure parameters and the experimental results demonstrates the complementarity of XRD, magnetic resonance experiments and theoretical methodologies. 2005-150 Carvajal, JJ Parreu, I Sole, R Solans, X Diaz, F Aguilo, M Growth and structural characterization of Rb3Yb2(PO4)(3): A new material for laser and nonlinear optical applications CHEMISTRY OF MATERIALS 17, 2005, 6746-6754. We report the synthesis of a new stoichiometric Yb compound, Rb3Yb2(PO4)(3), by high-temperature solution methods. This is the first material of the A(3)(I)B(2)(III)((XO4)-O-V)(3) family containing a lanthanide element and the only one that shows optical activity. We resolved the structure of Rb3Yb2(PO4)(3), which crystallize in the cubic system, space group of symmetry I2(I)3 (a = 16.8700(10) angstrom, Z = 16). and studied its evolution with the temperature. The thermal expansion coefficient of Rb3Yb2(PO4)(3) is alpha = 8.94 x 10(-6) K-1. This compound melts incongruently at 1450 K. The second-harmonic generation efficiency of the Rb3Yb2-(PO4)(3), although limited as a result of the crystal not presenting birefringence, was at least similar to that of potassium dihydrogen phosphate. 2005-151 Casellas, N Gamez, P Reedijk, J Mutikainen, I Turpeinen, U Masciocchi, N Galli, S Sironi, A Moisture-triggered 1,3,5-triazine-based cull molecular switch: A combined X-ray single-crystal and powder diffraction study INORGANIC CHEMISTRY 44, 2005, 7918-7924. A solvothermal synthetic procedure has been exploited to prepare the new [Cu3L(NO3)(6)](n) coordination polymer (1) by reaction of the polydentate N,N'-{2,4-di-[(di-pyridin-2-yl)amine]-1,3,5-triazine}ethylenediamine ligand (opytrizediam Q with copper(II) nitrate. 1 has been structurally characterized by means of the conventional X-ray single-crystal diffraction technique. It crystallizes in the monoclinic C2/c space group with a = 16.830(3), b = 20.701(4), c = 18.170(4) angstrom, beta = 113.26(3)degrees, V= 5816(2) angstrom(3), Z = 4. 1 consists of trinuclear Cu3L(NO3)(5) units connected by means of a nitrato-O,O' bridge. The resulting chains are involved in weak interchain head-to-tail pi-pi stacking interactions. In the presence of moisture, 1 is readily converted into the hydrated [Cu3L(NO3)(5)](NO3)center dot H2O form (2). This second phase, monoclinic P2(1)/c, consists of isolated [Cu3L(NO3)(5)](+) and (NO3)(-) ions which accommodate water molecules in the crystal lattice. These subtle chemical and structural modifications accompanying the moisture-triggered 1-to-2 transformation have been demonstrated through a X-ray powder diffraction study. A thermodiffractometric analysis has evidenced that this solid-to-solid transformation is fully reversible, i.e., thermally induced dehydration of 2 restores 1. The analysis of the temperature dependence of the magnetic susceptibility for 2 has revealed very weak ferromagnetic interactions, consistent with the large (CuCu)-Cu-... separation (ca. 7.5 angstrom) in the trinuclear units. 2005-152 AU Navarro, JAR Barea, E Galindo, MA Salas, JM Romero, MA Quiros, M Masciocchi, N Galli, S Sironi, A Lippert, B Soft functional polynuclear coordination compounds containing pyrimidine bridges JOURNAL OF SOLID STATE CHEMISTRY 178, 2005, 2436-2451. In this account, we describe the use of simple pyrimidine derivatives in combination with metal ions to build highly structured molecular architectures containing functional nanoenvironments, cavities and surfaces that can interact with additional species. The supramolecular structure of these systems can be rationally controlled by metal fragment geometry, reaction conditions and presence of templating agents. Thus, the use of transition metals with low coordination numbers or blocked bonding positions in combination with pyrimidines (e.g. 2-hydroxypyrimidine, 4-hydroxypyrimidine, 2,4-dihydroxypyrimidine, 2-aminopyrimidine) leads to the formation of either discrete assemblies, ID polymers or helixes. When metal ions with higher coordination possibilities are applied instead, 2D and 3D networks are generated. Some of the assemblies built in this way possess functional cavities, pores and surfaces that can interact with additional species by means of hydrophobic, electrostatic, H-bonding interactions and coordinative bonds to give rise to recognition processes. The latter range from molecular recognition in homogeneous phase as well as clathrate formation, to heterogeneous solid-gas and solid-liquid adsorption phenomena. It should be noted that these materials are not rigid but able to undergo guest-induced reorganisation processes even in the solid state. Finally, some of these materials also combine additional interesting magneto-optical properties. Thus, dual systems can be envisaged in which two or more of these properties are present in the same material. 2005-153 Cingolani, A Galli, S Masciocchi, N Pandolfo, L Pettinari, C Sironi, A Sorption-desorption behavior of bispyrazolato-copper(II) 1D coordination polymers JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127, 2005, 6144-6145 2005-154 2004-1 Pagola, S Benavente, A Raschi, A Romano, E Molina, MAA Stephens, PW Crystal structure determination of thymoquinone by high-resolution X-ray powder diffraction AAPS PHARMSCITECH 5, 2004, 28 The crystal structure of 2-isopropyl-5-methyl-1,4-benzoquinone ( thymoquinone) and its thermal behavior - as necessary physical and chemical properties - were determined in order to enhance the current understanding of thymoquinone chemical action by using high resolution x-ray powder diffraction, Fourier transform infrared spectroscopy ( FTIR), and 3 thermo-analytical techniques thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimetry (DSC). The findings obtained with high-resolution x-ray powder diffraction and molecular location methods based on a simulated annealing algorithm after Rietveld refinement showed that the triclinic unit cell was a = 6.73728( 8) Angstrom, b = 6.91560( 8) Angstrom, c = 10.4988( 2) Angstrom, alpha = 88.864( 2)degrees, beta = 82.449( 1) degrees, gamma = 77.0299( 9)degrees; cell volume = 472.52( 1) Angstrom(3), Z = 2, and space group 1 (1) over bar. TREOR 2004-2 Gomez, A Rodriguez-Hernandez, J Reguera, E Unique coordination in metal nitroprussides: The structure of Cu[Fe(CN)(5)NO] . 2H(2)O and Cu[Fe(CN)(5)NO] JOURNAL OF CHEMICAL CRYSTALLOGRAPHY 34, 2004, 893-903. The structures of copper pentacyanonitrosylferrate dihydrate, Cu[Fe(CN)(5)NO].2H(2)O, and anhydrous, Cu[Fe(CN)(5)NO], have been determined from their XRD powder patterns and refined using the Rietveld method. The dihydrate structure was solved by direct methods and the anhydrous one was elucidated by chemical intuition. Cu[Fe(CN)(5)NO].2H(2)O is orthorhombic, space group Amm2 (38) and Z=2. In this structure the iron is coordinated to five CN and a NO ligand, while the copper atom is coordinated, in a unique fashion, to four equatorial CN groups at N ends and two water molecules. Cu[Fe(CN)(5)NO] is tetragonal, space group I4 mm (107) and Z=2. This structure is obtained from the dehydration of the orthorhombic one; reordering allows the Cu atom to coordinate not only to the four equatorial cyanides but also to the axial cyanide. The coordination of the iron atom remains as in the orthorhombic structure. Agreement factor obtained from the final refinement were as follows: R-wp=5.10 and R-B=4.57 for the orthorhombic structure and R-wp=6.52 and R-B=7.82 for the tetragonal one. These crystal structures are also supported by IR and Mossbauer spectroscopic data and thermogravimetry. TREOR 2004-3 Vivani, R Costantino, F Nocchetti, M Gatta, GD Structural homologies in benzylamino-N,N-bis methylphosphonic acid and its layered zirconium derivative JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 4013-4022. A new layered zirconium diphosphonate fluoride, ZrF(O3PCH2)(2)NHCH2C6H5 has been prepared and its structure determined ab initio by X-ray powder data and refined with the Rietveld method (orthorhombic, a = 8.9429(2) Angstrom, b = 9.1746(2) Angstrom, c = 31.5654(7) Angstrom, space group Pbca, V = 2589.9(1) Angstrom(3), Z = 8, R-wp = 0.080). TREOR, DICVOL 2004-4 Atkinson, TD Fjellvag, H Kjekshus, A Synthesis, structure, and properties of chromium(III) sulfates JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 4351-4358. Reactions between CrO3 and 50-95 wt% H2SO4 are studied at temperatures up to the boiling point of the acid. Depending on the H2SO4 concentration and synthesis temperature, Cr-2(SO4)(3), CrH(SO4)(2), (H3O)[Cr(SO4)(2)], Cr-2(SO4)(3) . H2SO4 . 4H2O (gross formula), and (H5O2)[Cr(H2O)(2)(SO4)(2)], are obtained as identified reaction products in addition to the incompletely characterized chromic-sulfuric acid. The Cr-III-based sulfates are characterized by X-ray powder diffraction, thermogravimetric, and magnetic susceptibility measurements. The nuclear and magnetic structures of Cr-2(SO4)(3) at 10 K are determined, the structure type of (H3O)[Cr(SO4)(2)] is established, and the crystal structure of (H5O2)[Cr(H2O)(2)(SO4)(2)] is firmly stipulated. TREOR 2004-5 Chernyshev, VV Stephens, PW Yatsenko, AV Ryabova, OB Makarov, VA Structural characterization of prazosin hydrochloride and prazosin free base JOURNAL OF PHARMACEUTICAL SCIENCES 93, 2004, 3090-3095. three-dimensional solid-state structures of prazosin hydrochloride, C19H22N5O4+ . Cl- (A), and prazosin free base, C19H21N5O4 (B), have been determined by synchrotron X-ray powder diffraction. A and B crystallize in triclinic P-1 and monoclinic Cc space groups, respectively, with one structural unit per asymmetric part. In A and B, the prazosin molecule adopts different conformations, which do not correspond to those obtained by DFT optimizations of protonated and free prazosin. TREOR 2004-5 Cremer, U Disch, S Ruschewitz, U CaCu(C2H)(3) . 6 NH3 and Rb2Cu(C2H)(3) . NH3: Two ethinylocuprates with a trigonal planar [Cu(C2H)(3)](2-) anion ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 630, 2004, 2304-2310. By reactions in liquid ammonia Ca[Cu(C2H)(3)] (.) 6 NH3 and Rb-2[Cu(C2H)(3)](.) NH3 were obtained as polycrystalline solids. The new compounds are very sensitive against loss of ammonia and are only stable in a NH3 atmosphere at room temperature. Structural investigations based on X-ray powder diffraction data resulted in hexagonal unit cells (Ca[Cu(C2H)(3)] (.) 6 NH3: P6(3)mc, Z = 2, a = 986,39(1) pm, c = 926,47(1) pm; Rb-2[Cu(C2H)(3)] (.) NH3: P6(3)/m, Z = 6, a = 1096,46(2) pm, c = 1600,15(3) pm). TREOR 2004-6 Fantin, G Fogagnolo, M Bortolini, O Masciocchi, N Galli, S Sironi, A Structural and analytical powder diffraction studies of the enantioselective inclusion of chiral arylmethylsulfoxides in dehydrocholic acid cocrystals NEW JOURNAL OF CHEMISTRY 28, 2004, 1295-1300. Dehydrocholic acid (DHA) has been employed in the separation of chiral arylmethylsulfoxides through selective precipitation of highly enriched 1 : 1 cocrystals of p-XC6H4SOMe@DHA (X = Me, OMe, Br, H) formulation. X-ray powder diffraction (XRPD) has shown that two, nearly isomorphous, but distinct classes of compounds are obtained. Their complete structural analysis has been performed by ab initio XRPD methods. TREOR 2004-7 Ivashkevich, LS Lyakhov, AS Selevich, AF Lesnikovich, AI Crystal structure determination of In-3(H3O)(H2PO4)(6)(HPO4)(2)center dot 4H(2)O from X-ray powder diffraction ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 543-547. The crystal structure of indium hydrogen phosphate hydrate, In-3(H3O)(H2PO4)(6)(HPO4)(2) . 4 H2O, has been determined from X-ray powder diffraction data by using direct methods (EXPO program), and refined by FULLPROF package to R-Bragg value of 5.6%. The structure is monoclinic, space group C2/c (No. 15), unit cell dimensions a = 17.0835(5), b = 9.6795(3), c = 17.8776(4) Angstrom, beta = 90.301(2)degrees, V = 2956.2(1) Angstrom(3), Z = 4, D-x = 2.73 g/cm(3). Hydrogen atoms were placed on calculated positions. There are two unique indium atoms in the crystal structure. InO6 octahedra are connected together via the corners of PO4 tetrahedra to form layers parallel to the xy plane. The layers are linked to-ether by water molecules, located in the interlayer space, through their hydrogen bonds. Within the layers there are hollows occupied by oxonium cations. The compound was found to be isostructural with salts of the composition M-III M-3(I)(H2PO4)(6)(HPO4)(2) . 4 H2O, where M-III - trivalent metal, M-I - monovalent metal, oxonium or ammonium. TREOR 2004-8 Robins, ELR Brunelli, M Mora, AJ Fitch, AN Low-temperature crystal structure of RS-thiocamphor ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 580-583. DSC and high-resolution powder X-ray diffraction measurements in the range 295 K-100 K show that RS-thiocamphor undergoes two phase transitions. The first, at around 260 K on cooling, is from the room-temperature body-centred-cubic phase to a short-lived intermediate. At 258 K the low-temperature form starts to appear. The crystal structure of the latter is orthorhombic, space group Pbnm, with a = 9.0643(4) Angstrom, b = 14.6714(8) Angstrom, c = 7.2878(4) Angstrom, Z = 4, rho(calc) = 1.15 g cm(-3) at 100 K. The structure is twofold disordered, with the enantiomers superimposed in the average structure, related by the mirror plane. TREOR, Sync 2004-9 Mathieu, Y Paillaud, JL Caullet, P Bats, N Synthesis and characterization of IM-10: a new microporous silicogermanate with a novel topology MICROPOROUS AND MESOPOROUS MATERIALS 75, 2004, 13-22. A novel GeO2 or (Si,Ge)O-2 zeolite phase called IM-10 was obtained in the presence of the well-known hexamethonium ion as template and in fluoride media, from gels with Ge/Si molar ratios greater than or equal to 1. With decrease of the Ge/Si molar ratio, BEC-type zeolite and ITH-type zeolite were successively obtained. The recovered IM-10 samples were characterized by X-ray diffraction, SEM, elemental and thermal analysis, F-19 MAS and H-1 liquid (after dissolution of the samples in HF) spectroscopies. Due to the small crystal sizes (1-4 mum), the structure was determined from powder X-ray diffraction (of the GeO2 as-made sample) and refined by the Rietveld method. IM-10 is a new member of the clathrate family. It crystallizes in the tetragonal symmetry, the space group being P (4) over bar n2. The framework is made of F--containing D4R units, bridged by GeO4 tetrahedra. The arrangement of the D4R units creates [6(20)4(2)] supercages, each of them occluding one hexamethonium cation. Structural similarities exist between ASU-9 (AST), ASU-7 (ASV) and the new IM-10 zeolite with a novel topology (UOZ). TREOR 2004-10 Ma, HW Liang, JK Wu, L Liu, GY Rao, GH Chen, XL Ab initio structure determination of new compound Ba-3(BO3)(PO4) JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 3454-3459. Ba3BPO7; borophosphate; structure determinations; x-ray powder diffraction The crystal structure of new compound Ba3BPO7 was determined by ab initio method from high-resolution conventional X-ray powder diffraction data. The Rietveld refinement converged to R-p = 5.92%, R-wp = 8.87%, R-exp = 5.00% with the following details: Hexagonal, space group P6(3)mc, a = 5.4898 (1) Angstrom, c = 14.7551 (1) Angstrom, Z = 2. TREOR 2004-11 Fukuda, K Moriyama, A Hashimoto, S Crystal structure and phase transitions of strontium zirconium diorthophosphate, SrZr(PO4)(2) JOURNAL OF SOLID STATE CHEMISTRY 177,2004,3514-3521. The crystal structure of SrZr(PO4)(2) at 298 K was determined from conventional X-ray powder diffraction data using direct methods, and it was further refined by the Rietveld method. The structure was triclinic (space group P (1) over bar, Z = 2) with a = 0.77508(4) nm, b = 0.78887(5) nm, c = 0.51251(3) nm, alpha = 95.754(3)degrees, beta = 90.228(2)degrees, gamma = 92.474(2)degrees, and V = 0.31149(3) nm(3). Final reliability indices were R-wp = 8.51%, R-P = 6.07%, and R-B = 2.46%. The powder specimens were also examined by high-temperature XRD and differential thermal analysis to reveal the occurrence of phase transitions from triclinic to monoclinic at 405 K, then to hexagonal (or trigonal) at 1196 K during heating. Upon cooling, the reverse change of the latter transition occurred at 1175 K. The subsequent monoclinic-to-triclinic transition was martensitic and incomplete during further cooling to 298 K. The monoclinic phase is most probably isostructural with yavapaiite. The present paper has described, for the first time, the higher- and lower-temperature polymorphs of the yavapaiite-type structure. TREOR 2004-12 Millini, R Carluccio, LC Carati, A Bellussi, G Perego, C Cruciani, G Zanardi, S ERS-12: A new layered tetramethylammonium silicate composed by ferrierite layers MICROPOROUS AND MESOPOROUS MATERIALS 74, 2004, 59-71. The new layered silicate ERS-12 was synthesized using tetraethylorthosilicate (TEOS) as source of silica and tetramethylammonium hydroxide (TMA-OH) as a structure directing agent. ERS-12 crystallizes also as germanosilicate, but not as alumino- and titanosilicate. Structure determination of as-synthesized ERS-12 was performed using alpha combined approach of experimental and molecular modeling techniques. It is composed by a regular stacking of ferrierite layers, with the TMA cations located in the interlayer region. Rietveld refinement of the high resolution synchrotron X-ray diffraction (SXPD) pattern of as-synthesized ERS-12 structure was firstly carried out in the monoclinic P2(1)/m space group; however, to avoid the presence of linear Si-O-Si angles, final refinement was. performed in the acentric P2(1) space group, which gave unit cell parameters a = 10.5606 (2), b = 13.9692 (1), c = 7.4148(1) Angstrom, beta = 97.981(2)degrees and agreement factors of R-p = 8.9%, R-wp = 12.4% and R-F(2) = 12.2%. Upon calcination, a remarkable change of the SXPD pattern occurred with the contemporarily presence of sharp and asymmetrically broadened reflections, indicative of the formation of a disordered structure; this was confirmed by the DIFFaX study carried out in order to evaluate the stacking sequences of ferrierite layers. The simulation suggested that the layers do not fully condense upon calcinations to form a completely connected framework. TREOR 2004-13 Bulychev, BM Shpanchenko, RV Antipov, EV Sheptyakov, DV Bushmeleva, SN Balagurov, AM Synthesis and crystal structure of lithium beryllium deuteride Li2BeD4 INORGANIC CHEMISTRY 43, 2004, 6371-6376. Single-phase ternary deuteride Li2BeD4 was synthesized by a high-pressure high-temperature technique from LiD and BeD2. The crystal structure of Li2BeD4 was solved from X-ray and neutron powder diffraction data. The compound crystallizes in the monoclinic space group P2(1)/c with lattice parameters a = 7.06228(9) Angstrom, b = 8.3378(1) Angstrom, c = 8.3465(1) Angstrom, beta=93.577(1)degrees, and Z = 8. Its structure contains isolated BeD4 tetrahedra and Li atoms that are located in the structure interstices. Li2BeD4 does not undergo any structural phase transitions at temperatures down to 8 K. TREOR 2004-14 Hull, S Berastegui, P Crystal structures and ionic conductivities of ternary derivatives of the silver and copper monohalides - II: ordered phases within the (AgX)(x)-(MX)(1-x) and (CuX)(x)-(MX)(1-x) (M = K, Rb and Cs; X = Cl, Br and I) systems JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 3156-3173. The crystal structures of 23 ternary phases present in the systems (AX)(x)-(MX)(1-x) (A = Ag, Cu; M= K, Rb and Cs; X= Cl, Br and 1) have been determined and/or refined using X-ray and neutron diffraction studies of powder samples. A total of 11 x = 0.333 phases of stoichiometry M(2)AX(3) are found (Rb2AgCl3, Cs2AgCl3, Rb2AgBr3, Cs2AgBr3, K2AgI3, Rb2AgI3, Cs2AgI3, K2CuCl3, K2CuBr3, Rb2CuBr3 and Rb2CuCl3) which crystallize in one of two closely related crystal structures with space group Pnma. The x = 0.4 composition is characterized by three compounds Cs3Cu2X5 (X= Cl, Br, 1) which all adopt space group Pnma, whilst the x = 0.5 case comprises the two compounds CsAgCl2 and CsAgBr2, which possess space group Cmcm. The latter undergo phase transitions at 408(5) and 413(8) K, respectively, to higher symmetry structures in space group P4/nmm. Five x = 0.667 compounds of stoichiometry MCu2X3 have been identified (CsCu2Cl3, CsCu2Br3, CsCu2I3, RbCu2Br3, and RbCu2I3). Together with CsAg2I3, these form a family of compounds, which crystallize in one of two closely related structures (space group Pbnm or Cmcm). 2004-15 Vicente, J Gil-Rubio, J Bautista, D Sironi, A Masciocchi, N Synthesis and reactivity of fluoro complexes: Part 2. Rhodium(I) fluoro complexes with alkene and phosphine ligands. Synthesis of the first isolated rhodium(I) bifluoride complexes. Structure of [Rh-3(mu(3)-OH)(2)(COD)(3)](HF2) by X-ray powder diffraction INORGANIC CHEMISTRY 43, 2004, 5665-5675. The reaction between [Rh(mu-OH)(COD)](2) (COD = 1,5-cyclooctadiene) and 73% HF in THF gives [Rh-3(mu(3)-OH)(2)(COD)(3)](HF2) (1). Its crystal structure, determined by ab initio X-ray powder diffraction methods (from conventional laboratory data), contains complex trimetallic cations linked together in 1 D chains by a mu(3)-OH... F-H-F... HO-mu(3) sequence of strong hydrogen bonds. The complex [Rh(mu-F)(COE)(2)](2) (COE = cyclooctene; 2), prepared by reacting [Rh(u-OH)(COE)(2)](2) with NEt3.3HF (3:2), has been characterized. Complex 1 reacts with PR3 (1:3) to give [RhF(COD)(PR3)] [R = Ph (3), C6H4OMe-4 (4), Pr-i (5), Cy (6)] that can be prepared directly by reacting [Rh(U-OH)(COD)](2) with 73% HF and PR3 (1:2:2). The reactions of 1 with PPh3 or Et3P have been studied by NMR spectroscopy at different molar ratios. Complexes [RhF(PEt3)(3)] (7), [RhF(COD)(PEt3)] (8), and [RhF(PPh3)(3)] (9) have been detected. The complex [Rh(F)(NBD)(Pr3P)] (NBD = norbornadiene; 10) was prepared by the sequential treatment of [Rh(mu-OMe)(NBD)](2) with 1 equiv of NEt3.3HF and Pr3P. The first isolated bifluoride rhodium(I) complexes [Rh(FHF)(COD)(PR3)] [R = Ph (11), Pr-i (12), Cy (13)], obtained by reacting fluoro complexes 3, 5, and 6 with NEt3.3HF (3:1), have been characterized. The crystal structures of 3 and 11 have been determined. TREOR 2004-16 Gomez-Alcantara, MM Cabeza, A Martinez-Lara, M Aranda, MAG Suau, R Bhuvanesh, N Clearfield, A Synthesis and characterization of a new bisphosphonic acid and several metal hybrids derivatives INORGANIC CHEMISTRY 43, 2004, 5283-5293. Commercial bis-(4-bromophenyl)-ether, [BrC6H4](2)-O, has been used to prepare 4-[4'-(diethoxyphosphoryl)phenoxy]phenyl-phosphonic acid diethyl ester, [(CH3CH2)(2)O3P-C6H4](2)-O, (I) following a slight modification of the Michaelis-Arbuzov reaction. The acid hydrolysis of I gave 4-(4'-phosphonophenoxy)phenyl phosphonic acid, [H2O3P-C6H4](2)-O (II), and both compounds have been characterized by H-1 NMR and C-13 NMR. The crystal structure of II has been determined by single-crystal X-ray diffraction. II crystallizes in an orthorhombic unit cell, space group Pbcn, with a = 7.822(3) Angstrom, b = 5.821(2) Angstrom, c = 28.982(9) Angstrom, and V = 1319.7(7) Angstrom(3). The final R factor was R1 = 0.0614. The structure is layered, being held together through a hydrogen bonding network. II has been used as precursor in the syntheses of new metal (Mn, Fe, Co, Ni, Cu, and Zn) bisphosphonates. The syntheses were carried out using a fixed metal/bisphosphonic acid molar ratio of 2.1:1 and the influence of the pH in the reactions has been studied. Nine new compounds have been isolated: Mn-2(O3PC6H4OC6H4PO3)(.)1.5H(2)O (III), Mn-5(OH)(2)(O3PC6H4OC6H4PO3)(2)(.)2H(2)O (IV), Fe(HO3PC6H4OC6H4PO3)(.)0.5H(2)O M, CO2(O3PC6H4OC6H4PO3)(.)2H(2)O (VI), Ni-2(O3PC6H4OC6H4PO3)(.)3H(2)O (VII), Ni-2(O3PC6H4OC6H4PO3)(.)2H(2)O (VIII), Cu-2(O3PC6H4OC6H4PO3) (IX), Zn-2(O3PC6H4OC6H4PO3) (X), and Zn(HO3PC6H4OC6H4PO3H) (XI). Compound IX crystallizes in an orthorhombic unit cell, space group Pbcn, and unit cell parameters a = 8.1012(5) Angstrom, b = 5.3109(3) Angstrom, c = 29.2595(5) Angstrom, and V = 1258.8(1) Angstrom(3). Its structure has been solved by ab initio powder diffraction and refined by the Rietveld method to R-F = 0.042. IX has a pillared layer framework with highly distorted CuO5 groups sharing edges to give isolated dimers. XI was indexed in a monoclinic unit cell, space group P112(1), with parameters a = 9.4991 (9) Angstrom, b = 5.0445(5) Angstrom, c = 29.131(2) Angstrom, gamma = 91.945(7)degrees, and V = 1395.1(3) Angstrom(3). Its structure has been refined by the Rietveld method, R-F = 0.054, since it is isostructural with the known compound, Zn[HO3P(C6H4)(2)PO3H]. All solids were also characterized by thermal analysis and IR and UV-Vis spectroscopies. TREOR 2004-17 Chernaya, VV Tsirlin, AA Shpanchenko, RV Antipov, EV Gippius, AA Morozova, EN Dyakov, V Hadermann, J Kaul, EE Geibel, C Crystal structure and properties of Na2MVO(PO4)(2), the new vanadyl(IV)phosphates M=Ca and Sr JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 2875-2880. Two new complex vanadyl(IV)phosphates Na2MVO(PO4)(2) (M = Ca, Sr) were synthesized in evacuated quartz ampoules and investigated by means of X-ray diffraction, electron microscopy, DTA, ESR and magnetic susceptibility measurements. The crystal structure of Na2SrVO(PO4)(2) was solved ab initio from X-ray powder diffraction data. Both compounds are isostructural: a = 10.5233(3) Angstrom, b = 6.5578(2) Angstrom, c = 10.0536(3) Angstrom and a = 10.6476(3) Angstrom, b = 6.6224(2) Angstrom, c = 10.2537(3) Angstrom for Ca and Sr, respectively; S.G. Pnma, Z = 4. The compounds have a three-dimensional structure consisting of V4+ O-6 octahedra connected by PO4 tetrahedra via five of the six vertexes forming a framework with cross-like channels. The strontium and sodium atoms are located in the channels in an ordered manner. Electron diffraction as well as high-resolution electron microscopy confirmed the structure solution. The new vanadylphosphates are Curie-Weiss paramagnets in a wide temperature range down to 2 K with theta = 12 and 5 K for Ca and Sr phases, respectively. TREOR 2004-18 Albov, DV Davydov, DV Chernyshev, VV Di-mu-hydroxo-bis[(N,N,N ',N '-tetramethylethylenediamine)copper(II)] dichloride from X-ray powder data ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 60, 2004, M1193-M1195. The crystal structure of the title complex, [Cu-2(OH)(2)-(TMEDA)(2)]Cl-2 (TMEDA is N,N,N',N'-tetramethylethylene-diamine, C6H16N2) has been characterized by X-ray powder diffraction. The cation is a binuclear complex with a Cu...Cu distance of 3.031 (7) Angstrom and occupies a special position of 222 symmetry, while the chloride anions are on a twofold axis. There is a hydrogen bond linking a bridging hydroxy group with the anion [O...Cl = 2.993 (14) Angstrom]. TREOR 2004-19 Filonenko, VP Sundberg, M Werner, PE Zibrov, IP Structure of a high-pressure phase of vanadium pentoxide beta-V2O5 ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 60, 2004, 375-381. A high-pressure phase of vanadium pentoxide, denoted beta-V2O5, has been prepared at P = 6.0 GPa and T = 1073 K. The crystal structure of beta-V2O5 has been studied by X-ray and neutron powder diffraction, and high-resolution transmission electron microscopy. The V atoms are six-coordinated within distorted VO6 octahedra. The structure is built up of quadruple units of edge-sharing VO6 octahedra linked by sharing edges along [ 010] and mutually connected by sharing corners along [001]. This arrangement forms layers of V4O10 composition in planes parallel to ( 100). The layers are mutually held together by weak forces. beta-V2O5 is metastable and transforms to alpha-V2O5 at 643 - 653 K under ambient pressure. Structural relationships between beta- and alpha-V2O5, and between beta-V2O5 and B-Ta2O5-type structures are discussed. The high-pressure beta-V2O5 layer structure can be considered as the parent of a new series of vanadium oxide bronzes with cations intercalated between the layers. TREOR 2004-20 Platteau, C Lefebvre, J Affouard, F Derollez, P Ab initio structure determination of the hygroscopic anhydrous form of a-lactose by powder X-ray diffraction ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 60, 2004, 453-460. Annealing of alpha-lactose monohydrate at 408 K yielded a mixture of this compound with hygroscopic anhydrous alpha-lactose. A powder X-ray diffraction pattern of this mixture was recorded at room temperature. The starting structural model of hygroscopic alpha-lactose was found by a Monte Carlo simulated-annealing method. The final structure was obtained through Rietveld refinements, with soft restraints on interatomic bond lengths and bond angles, and crystalline energy minimization to locate the H atoms of the hydroxy groups. The crystalline cohesion is achieved by networks of O - H ... O hydrogen bonds that differ from those of the monohydrate phase. The width of the Bragg peaks is interpreted by a phenomenological microstructural approach in terms of isotropic size effects and anisotropic strain effects. TREOR 2004-21 Rosdahl, J Persson, I Lars, K Stahl, K On the solvation of the mercury(I) ion. A structural, vibration spectroscopic and quantum chemical study INORGANICA CHIMICA ACTA 357, 2004, 2624-2634. The structure of solid anhydrous mercury(l) trifluoromethanesulfonate, Hg-2(CF3SO3)(2) (1), has been determined by powder diffraction methods. The structure comprises of discrete molecules, where each mercury binds to an oxygen atom in the anion, forming an almost linear O-Hg-Hg-O entity; the Hg-Hg-O angle is 173degrees and the Hg-Hg and Hg-O bond lengths are 2.486(6) and 2.099(22) Angstrom, respectively. TREOR 2004-22 Kyoi, D Sato, T Ronnebro, E Tsuji, Y Kitamura, N Ueda, A Ito, M Katsuyama, S Hara, S Noreus, D Sakai, T A novel magnesium-vanadium hydride synthesized by a gigapascal-high-pressure technique JOURNAL OF ALLOYS AND COMPOUNDS 375, 2004, 253-258. A magnesium-based vanadium-doped hydride was prepared in a high-pressure anvil cell by reacting a MgH2-25%V molar mixture at 8 GPa and 873 K. The new magnesium-vanadium hydride has a cubic F-centred substructure (a = 4.721 (1) Angstrom), with an additional superstructure, which could be described by a doubling of the cubic cell axis and a magnesium atom framework, including an ordered arrangement of both vanadium atoms and vacancies (a = 9.437(3) Angstrom, space group Fm (3) over barm (no. 225), Z = 4, V = 840.55,Angstrom(3)). The metal atom structure is related to the Ca7Ge type structure but the refined metal atom composition with vacancies on one of the magnesium sites corresponding to Mg6V nearly in line with EDX analysis. TREOR 2004-23 Song, GB Han, CQ Chen, XL Liang, JK Liu, QL Zhou, YQ Liu, FS Rao, GH Subsolidus phase relations and crystal structure of compounds in the PrOx-CaO-CuO system JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 2394-2404. The subsolidus phase relations of the PrOx-CaO-CuO pseudo-ternary system sintered at 950-1000degreesC have been investigated by X-ray powder diffraction. In this system, there exist one compound Ca10Pr4Cu24O41, one Ca2Pr2Cu5O10-bascd solid solution, seven three-phase regions and two two-phase regions. The crystal structures of Ca10Pr4Cu24O41, and Ca2Pr2Cu5O10-based solid solution have been determined. Compound Ca10Pr4Cu24O41 crystallizes in an orthorhombic cell with space group D-2h(20) - Cccm, Z = 4. Its lattice parameters are a = 11.278(2) Angstrom, b = 12.448(3) Angstrom and c = 27.486(8) Angstrom. The crystal structure of Ca2Pr2Cu5O10-based solid solution is an incommensurate phase based on the orthorhombic NaCuO2 type subcell. The lattice parameters of the subcell of the Ca2.4Pr1.6Cu5O10 are a(0) = 2.8246(7) Angstrom, b(0) = 6.3693(5) Angstrom, c(0) = 10.679(1) Angstrom, and those of the orthorhombic superstructure are with a = 5a(0), b = b(0), c = 5c(0). The Ca2.4Pr1.6Cu5O10 structure can also be determined by using a monoclinic supercell with space group C-2h(5) - P2(1)/c, Z = 4, a = 5a(0), b = b(0), c = c(0)/sin beta and beta = 104.79(1)degrees or 136.60(1)degrees, V = 5a(0)b(0)c(0). TREOR 2004-24 Bellitto, C Bauer, EM Righini, G Altomare, A Synthesis and magnetic properties of a new Cr(II) ammonium-ethyl-phosphonate: Cr-1.5[H3N(CH2)(2)PO3](SO4) . 2H(2)O JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 272-76, 2004, 1060-1061. A new molecule based magnet of formula Cr-1.5[H3N(CH2)(2)PO3](SO4) (.) 2H(2)O has been prepared and characterized. The magnetization vs. field and temperature measurements revealed the compound to be a soft weak-ferromagnet at T-N = 4.9 K. TREOR 2004-25 Botez, CE Stephens, PW Omotoso, O Crystal structure of dicalclum chromate hydrate POWDER DIFFRACTION 19, 2004, 133-136. Direct methods and Rietveld analysis were applied to high-resolution synchrotron X-ray powder diffraction data to solve the crystal structure of dicalcium chromate hydrate (Ca2CrO5.3H(2)O). The compound crystallizes in monoclinic symmetry (space group Cm, Z=2), with a =8.23575(5) Angstrom, b=7.90302(4) Angstrom, c=5.20331(3) Angstrom, and beta=98.0137(3)degrees. The structure is built from double-layers of CrO4 tetrahedra and CaO8 polyhedra that run parallel to the (001) plane. TREOR, DICVOL 2004-26 Ivashkevich, LS Lyakhov, AS Selevich, AF Lesnikovich, AI Crystal structure determination of Ga-3(H3O)H-8(PO4)(6) . 6 H2O from X-ray powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 267-271 The crystal structure of the gallium hydrogen phosphate hydrate, Ga-3(H3O)H-8(PO4)(6) (.) 6 H2O, has been determined from X-ray powder diffraction data. The structure is trigonal, space group P31c (No. 159), with unit cell dimensions a = 9.0227(1) Angstrom, c = 16.6389(3) Angstrom, V = 1173.08(3) Angstrom(3), Z=2, and D-x = 2.59g/cm(3). The structure was solved by direct methods using EXPO program and refined by FULLPROF package to R-Bragg value of 8.6%. Positions of hydrogen atoms were not defined. There are three unique gallium atoms in the crystal structure, having octahedral oxygen coordination. GaO6 octahedra are linked together via the corners Of PO4 tetrahedra to form a three-dimensional network with channels running along the c axis. There are two types of water molecules in the crystal, which essentially differ in their atomic environment. Oxonium cations, lying on crystallographic threefold axis, are surrounded by oxygen atoms of the phosphate groups and water molecules. TREOR 2004-27 Thoma, SG Bonhomme, F Cygan, RT Synthesis, crystal structure, and molecular modeling of a layered manganese(II) phosphate: Mn-3(PO4)(4) . 2(H3NCH2CH2)(3)N center dot 6(H2O) CHEMISTRY OF MATERIALS 16, 2004, 2068-2075. A novel layered manganese(II) phosphate, Mn-3(PO4)(4).2(H3NCH2CH2)(3)N.6(H2O), has been synthesized solvothermally using tris(2-aminoethyl)amine (TREN) as a template. The structure was solved A initio using X-ray powder diffraction data and confirmed by molecular modeling. The compound crystallizes in the trigonal space group P $(3) over bar $ c1 with a = 8.8706(4) Angstrom, c = 26.158(2) Angstrom, and V= 1782.6(2) Angstrom(3). The structure consists of layers of corner sharing Mn(II)O-4 and PO4 tetrahedra forming infinite [Mn-3(PO4)(4)](6-)macroanions with 4.6 net topology, sandwiched by layers of TREN and water molecules. The protonated TREN molecules provide charge balancing for the inorganic sheets; the interlayer stability is accomplished mainly by a network of hydrogen bonds between water molecules and the inorganic macroanions. This hybrid organic/inorganic layered material can be reversibly dehydrated. TREOR 2004-28 Rukiah, M Lefebvre, J Descamps, M Hemon, S Dzyabchenko, A Ab initio structure determination of m-toluidine by powder X-ray diffraction JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 464-471. The powder X-ray diffraction pattern of the crystalline phase of m-toluidine has been recorded with a sensitive curved detector (CPS120) at 150 K. The structure has been solved by real-space methods ( simulated annealing) followed by Rietveld refinements with phenyl rings as rigid bodies and with soft constraints on bond lengths for peripheral atoms. The cell is monoclinic with space group P2(1)/c and Z = 8. Equivalent molecules form chains along c. The crystalline cohesion is achieved by N-H...N hydrogen bonds between neighbouring chains of non-equivalent molecules and by van der Waals interactions of neighbouring chains of equivalent molecules. The hydrogen-bonding network has been confirmed by lattice-energy minimization. Anisotropic strain effects of the cell have been calculated. The directions of the minimal strains correspond to the directions of the hydrogen bonds. An explanation of the difficulty to crystallize the metastable phase is given. TREOR, N-TREOR 2004-29 Vila, E Rojo, JM Iglesias, JE Castro, A Polymorphism and electrical properties in the new oxide Bi6Mo2O15 CHEMISTRY OF MATERIALS 16, 2004, 1732-1739. A new oxide of composition Bi6Mo2O15 has been isolated in the binary system Bi2O3- MoO3. A wet-chemistry procedure, different from coprecipitation, has been used to prepare a nanosized, very reactive precursor. Annealing at different temperatures and for different time lengths leads to isolated polycrystalline polymorphs. X-ray powder diffraction studies on the hitherto unknown low-temperature form, L-Bi6Mo2O15, show that it crystallizes in the monoclinic system, with unit-cell parameters a = 29.0674(5) Angstrom, b = 5.64795(7) A, c 8.6620(1) Angstrom, beta = 97.979(1)degrees, and V = 1408.3 Angstrom(3). The high-temperature polymorph, H-Bi6Mo2O15, belongs to the well-known [Bi12O14] columnar structural type. The relationship between the unit-cell parameters of both phases points at the connection of their structural frameworks. Impedance spectroscopy measurements show that the transition L-H-Bi6Mo2O15 is partially reversible, as well as the existence of a second high-temperature phase H', similar to H. In contrast, the transition H-->H'-Bi6Mo2O15 is not reversible. These materials turn out to be good ionic conductors, with conductivities in the order L < H < H' for all temperatures tested. 2004-30 Pan, ZG Cheung, EY Harris, KDM Constable, EC Housecroft, CE Structural aspects of a dendrimer precursor determined directly from powder X-ray diffraction data CRYSTAL GROWTH & DESIGN 4, 2004, 451-455. The structure of 3,5-dimethoxybenzyl alcohol has been determined directly from powder X-ray diffraction data using the genetic algorithm technique for structure solution followed by Rietveld refinement. This material is the precursor to a family of dendrimer materials, and structural features exhibited by 3,5-dimethoxybenzyl alcohol in the solid state may be important in the rationalization of higher generation dendrimer materials within this family. TREOR, DICVOL 2004-31 Ronnebro, E Kyoi, D Blomqvist, H Noreus, D Sakai, T Structural characterization of Mg3CrH similar to 6 - a new high-pressure phase synthesized in a multi-anvil cell at 8 GPa JOURNAL OF ALLOYS AND COMPOUNDS 368, 2004, 279-282. With modem X-ray diffraction refinement methods it was possible to identify the first phase in the Mg-Cr-H system, Mg3CrH-6 from minute sample volume in spite of poor crystallinity and coexisting impurity phases. The new hydride was synthesized at 8 GPa in a high-pressure multi-anvil cell at 873 K. An orthorhombic unit cell was found with a = 9.635(2) Angstrom, b = 8.615(2) Angstrom, c = 4.8040(7) Angstrom, space group Pnam (no. 62) Z = 4. V = 398.77 Angstrom(3). Chromium is surrounded by a distorted cube of magnesium atoms with average Cr-Mg distances of 2.9(1) Angstrom. The hydrogen positions were not possible to determine, as only a small sample amount could be prepared. If the metal atom structure is compared to already known metal hydrides it can be concluded that Mg3CrH-6 consists of chromium hydrido complexes counterbalanced by magnesium ions. A high hydrogen content was confirmed with thermal desorption spectroscopy. TREOR 2004-32 Loiseau, T Serre, C Huguenard, C Fink, G Taulelle, F Henry, M Bataille, T Ferey, G A rationale for the large breathing of the porous aluminum terephthalate (MIL-53) upon hydration CHEMISTRY-A EUROPEAN JOURNAL 10, 2004, 1373-1382. Aluminum 1,4-benzenedicarboxylate Al(OH)[O2C-C6H4-CO2](.)[HO2C-C6H4-CO2H](0.70) or MIL-53 as (Al) has been hydrothermally synthesized by heating a mixture of aluminum nitrate, 1,4-benzenedicarboxylic acid, and water, for three days at 220degreesC. Its 3D framework is built up of infinite trans chains of corner-sharing AlO4(OH)(2) octahedra. The chains are interconnected by the 1,4-benzenedicarboxylate groups, creating ID rhombic-shaped tunnels. Disordered 1,4-benzenedicarboxylic acid molecules are trapped inside these tunnels. Their evacuation upon heating, between 275 and 420degreesC. leads to a nanoporous open-framework (MIL-53ht (Al) or Al(OH)[O2C-C6H4-CO2]) with empty pores of diameter 8.5 Angstrom. This solid exhibits a Langmuir surface area of 1590(1) m(2)g(-1) together with a remarkable thermal stability, since it starts to decompose only at 500degreesC. At room temperature, the solid reversibly absorbs water in its tunnels, causing a very large breathing effect and shrinkage of the pores. Analysis of the hydration process by solid-state NMR (H-1, C-13, Al-27) has clearly indicated that the trapped water molecules interact with the carboxylate groups through hydrogen bonds, but do not affect the hydroxyl species bridging the aluminum atoms. ne hydrogen bonds between water and the oxygen atoms of the framework are responsible for the contraction of the rhombic channels. The structures of the three forms have been determined by means of powder X-ray diffraction analysis. Crystal data for MIL-53 as (Al) are as follows: orthorhombic system, Pnma (no. 62), a 17.129(2), b = 6.628(1), c = 12.182(1) A; for MIL-53ht (Al), orthorhombic system, Imma (no. 74), a = 6.608(1), b = 16.675(3), c = 12.813(2) Angstrom; for MIL-53 lt (Al), monoclinic system, Cc (no. 9), a = 19.513(2), b = 7.612(1), c = 6.576(1) Angstrom, beta = 104.24(1)degrees. TREOR 2004-33 Ferreira, A Lin, Z Soares, MR Rocha, J Synthesis and ab initio structure determination from powder diffraction data of K4Sn2Si6O18 EUROPEAN POWDER DIFFRACTION EPDIC 8, MATERIALS SCIENCE FORUM, 443-4, 2004, 329-332. The crystal structure of a new potassium stannosilicate K4Sn2Si6O18 (AV-11) has been determined ab initio from powder X-ray diffraction data. The unit cell is trigonal, space group R3 (no. 146), Z=3 with cell dimensions a = 10.1587, c = 14.8039 Angstrom, gamma= 120degrees, V = 1323 Angstrom(3). The structure is made up of SnO6 octahedra and SiO4 tetrahedra by sharing comers. The SiO4 tetrahedra form a helix chain, periodically repeating every six tetrahedra. These chains extend along the [001] direction and are linked by isolated Sn-O octahedron giving a mixed framework. TREOR 2004-34 Scordari, F Ventruti, G Gualtieri, AF The structure of metahohmannite, Fe-2(3+)[O(SO4)(2)] . 4H(2)O, by in situ synchrotron powder diffraction AMERICAN MINERALOGIST 89, 2004, 365-370. Metahohmannite, Fe-2(3+)[O(SO4)(2)].4H(2)O, is a hydrated sulfate of ferric iron that occurs in sulfate deposits in the desert areas of Northern Chile. The compound used for this study was obtained as a dehydration product of hohmannite, Fe-2(3+)[O(SO4)(2)].(4+4)H2O. Intensities for the structure analysis were collected from a powdered sample using in situ synchrotron X-ray powder diffraction at ESRF (Grenoble, France). The structure was solved ab initio by profile deconvolution and the application of standard Patterson and difference Fourier maps. The structure was refined to R-p = 5.46% using the Rietveld method. Metahohmannite crystallizes in the triclinic system, space group P (1) over bar with unit-cell parameters a = 7.3484(5) Angstrom, b = 9.7710(6) Angstrom, c = 7.1521(5) Angstrom, alpha = 91.684(5)degrees, beta = 98.523 (5), gamma = 86.390(5)degrees, and Z = 2. The structure consists of four Fe3+ octahedra and four sulfate tetrahedra, which share vertices and edges to form a complex building block of Fe-4(3+)[O-2(SO4)(4)].8H(2)O composition. Such blocks are connected to form chains running parallel to the c axis. A complicated system of hydrogen bonds connects adjacent chains into a three-dimensional network. Finally, the crystal structures of metahohmannite, hohmannite, and amarantite are compared and the geometrical features discussed in detail. TREOR 2004-35 Muhle, C Dinnebier, RE van Wullen, L Schwering, G Jansen, M New insights into the structural and dynamical features of lithium hexaoxometalates Li7MO6 (M= Nb, Ta, Sb, Bi) INORGANIC CHEMISTRY 43, 2004, 874-881. We present a (re)investigation of the hexaoxometalates Li8MO6 (M = Sn, Pb, Zr, Hf) and Li7MO6 (M = Nb, Ta, Sb, Bi). Lithium motion and ionic conductivity in the hexaoxometalates were studied using impedance spectroscopy (for Li7MO6, M = Sb, Bi, Ta) and Li-6 and Li-7 solid-state nuclear magnetic resonance (for Li7TaO6). The NMR data indicate a considerable exchange of Li among the tetrahedral and octahedral voids even at ambient temperature. In an investigation of the crystal structures using laboratory and synchrotron X-ray powder diffraction techniques, the structures of Li7TaO6, Li7NbO6, and Li7SbO6 could be solved and refined. All three reveal a triclinic metric (Li7SbO6, triclinic, P (1) over bar, a = 5.38503(6) Angstrom, b = 5.89164(7) Angstrom, c = 5.43074(6) Angstrom, alpha = 117.2210(6)degrees, beta = 119.6311(6)0, gamma = 63.2520(7)degrees, V = 127.454(3) Angstrom(3), Z = 1; Li7NbO6, triclinic, P (1) over bar, a = 5.37932(9) Angstrom, b = 5.91942(11) Angstrom, c = 5.37922(9) Angstrom, alpha = 117.0033(9)-, beta = 119.6023(7)degrees, gamma = 63.2570(9)degrees, V = 126.938(4) Angstrom(3), Z = 1; Li7TaO6, triclinic, P (1) over bar, a = 5.38486(2) Angstrom, b = 5.92014(3) Angstrom, c = 5.38551(2) Angstrom, alpha = 117.0108(2)degrees, beta = 119.6132(2)degrees, gamma = 63,2492(2)degrees, V = 127.208(1) Angstrom(3), Z = 1. TREOR 2004-36 Bakhmutova-Albert, EV Bestaoui, N Bakhmutov, VI Clearfield, A Rodriguez, AV Llavona, R A novel cadmium aminophosphonate: X-ray powder diffraction structure, solid-state IR and NMR spectroscopic determination of the fine structure of the organic moieties INORGANIC CHEMISTRY 43, 2004, 1264-1272. A new divalent cadmium phosphonate, Cd2Cl2(H2O)(4)(H2L), has been synthesized from the ethylenediamine-N,N'-bis(methylenephosphonic acid) (H4L). The obtained microcrystalline compound has been characterized by solid-state IR spectra and C-13, P-31, and Cd-113 CP MAS NMR. The static P-13 NMR spectra have been also recorded to give the delta(11), delta(22), and delta(33) chemical shift parameters for both compounds. The spectral data, collected for Cd2Cl2-(H2O)(4)(H2L), are in an agreement with its X-ray powder diffraction structure solved with the cell dimensions a = 16.6105(10), b = 7.1572(4), and c = 6.8171(4) Angstrom and beta = 98.327(4)degrees. The octahedral coordination sphere of the cadmium atoms consists of two phosphonate oxygen atoms, two water oxygen atoms, and the two chlorine atoms. Cadmium atoms are bridged by the chlorine atoms forming four-membered rings. The phosphorus atoms exhibit a tetrahedral coordination with two oxygen atoms bonded to the cadmium atoms with P-O distances of 1.503(10) and 1.504(10) Angstrom. The third oxygen atom, showing a longer P-O distance (1.546(9) Angstrom), is not bonded to the metal center, nor is it bonded to a proton. The combined IR and NMR proton-phosphorus cross-polarization kinetic data together with the X-ray data confirm that the cadmium phosphonate has the zwitterionic structure (NH2+CH2P(O2Cd2)O-) similar to the initial aminophosphonic acid H4L. TREOR 2004-37 Barea, E Navarro, JAR Salas, JM Masclocchi, N Galli, S Sironi, A Coordination frameworks containing the pyrimidin-4-olate ligand. Synthesis, thermal, magnetic, and ab initio XRPD structural characterization of nickel and zinc derivatives INORGANIC CHEMISTRY 43, 2004, 473-481. Extended coordination frameworks containing the pyrimidin-4-olate ligand (4-pymo) and Zn(II) and Ni(II) metal ions have been obtained by solid state reactions and have been fully characterized by spectroscopic, thermal, and magnetic measurements and by ab initio XRPD. The reaction of ZnO and 4-Hpymo at 140 degreesC gives a solid microcrystalline phase, Zn(4-PYMO)(2) (1). Its 3D framework contains Zn(II) centers linked by 4-pymo ligands acting in two different coordination modes, namely, the N,N'- and the N,O-exo-bidentate ones, which result in a pseuclotetrahedral ZnN3O chromophore. Thermal treatment of the "molecular' Ni(4-pymo)(2)(H2O)(4) complex (2) above 140 degreesC gives an anhydrous amorphous material analyzing as Ni(4-PYMO)(2) (3a). Further heating of this material above 388 degreesC results in the formation of the microcrystalline layered Ni(4-PYMO)(2) species (3b), in which Ni(II) centers are bridged by N,O-exo-bidentate 4-pymo ligands (assisted by longer Ni...N contacts). The thermal dependence of the magnetic susceptibility has been studied for the paramagnetic species 2 and 3a. 2 shows a weak antiferromagnetic interaction [J = -0.313(5) cm(-1)] transmitted through the multiple H-bonding interactions between the exocyclic pyrimidine and water oxygen atoms coordinated to the metal centers. 3a behaves as a 2D Heisenberg antiferromagnet with J = -4.11(3) cm(-1). TREOR 2004-38 Vanhoyland, G Le Bail, A Mullens, J Van Poucke, LC Characterization and structure determination of ammonium bismuth oxalate hydrate, Bi(NH4)(C2O4)(2) . xH(2)O INORGANIC CHEMISTRY 43, 2004, 785-789. From on-line coupled TGA-MS and TGA-FTIR measurements, in combination with a quantitative chemical analysis, it was deduced that the chemical formula for an unknown bismuth oxalate compound had to be Bi(NH4)(C2O4)(2).3.71(6)H2O. Solution of the crystallographic structure on the basis of X-ray powder data proved this formula to be correct. The diffraction pattern was indexed by a tetragonal unit cell [a and c respectively 11.6896(2) and 9.2357(3) Angstrom; M-20 = 195 and F-30 = 302; Z(calc) = 4], from which the space group /4(1)/amd (No. 141) was derived. Direct methods were applied to solve the structure. The initial structural model was subsequently refined by means of the Rietveld method (R-B = 8.0%, R-wP = 14.0%). Bi is 8-fold coordinated by oxygen from the oxalate anions. Since these BiO8 polyhedrons do not share any edges or vertexes, an open framework is formed with water and ammonium molecules between. As a result, water can easily be removed, which is clearly indicated by the instant weight loss in the TGA upon heating. Moreover, as shown by HT-XRD, this process of water exchange is reversible as long as the heating temperature does not exceed 100 degreesC. TREOR, DICVOL 2004-39 Serda, P Grochowski, J Duddeck, H The structure of marmesinin by powder and single-crystal diffraction methods JOURNAL OF ALLOYS AND COMPOUNDS 362, 2004, 224-230. The crystal and molecular structure of marmesinin C20H24O9, a furocoumarine beta-D-glucoside, an important biocontrolling compound isolated from the fruits of Ammi majus L. was determined from high-resolution powder diffraction using simulated annealing and, independently, from microcrystal diffraction. Both structural models were in good agreement. High-resolution powder diffraction patterns recorded with synchrotron radiation proved to be an efficient method for crystal structure determination of poorly-crystallizing natural products. (C) 2003 Elsevier B.V. All rights reserved. TREOR 2004-40 Neels, A Wang, Y Stoeckli-Evans, H TStudying the structure of metal-organic polymers using in-house powder X-ray diffraction data: structural transformations induced by thermal treatment ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 892-901. The use of X-ray powder diffraction for the structure determination of inorganic, organic and metal-organic compounds has grown impressively over the last ten years. In supramolecular chemistry, the knowledge of the three-dimensional structure of a material is essential for the discussion of its macroscopic behaviour, and as a result the design of new functionalized materials. The ab initio crystal structure determination of previously unknown metal-organic compounds is still rare but is a field of high interest and activity. Here we describe the formation of ID coordination polymers and the phase transformation processes that lead to the formation of 3D polymers on heating, accompanied by colour changes. The reaction of pyrazine-2,5-dimethyl-3,6-dicarboxylic acid with first row transition metal salts lead to the formation of coordination polymers always in the form of microcrystalline powders. With manganese and nickel salts isostructural 1D coordination polymers were obtained. With zinc chloride and copper chloride isomorphous ID coordination polymers were obtained. The thermal decomposition of the nickel and copper polymers were studied and it was shown that on the loss of the coordinated water molecules new 3D coordination polymers could be obtained. In both the ID and 3D coordination polymers the metal atoms have octahedral geometry in N2O4 environments. The crystal structures of all six complexes have been determined from powder X-ray diffraction data. Crystal data: (1) crystal symmetry monoclinic [space group P2(1)/c, a = 7.4645(1), b = 8.9472(2), c = 7.6166(1) Angstrom, beta = 92.198(2)degrees]; (2) crystal symmetry orthorhombic [space group Pbcn, a = 7.4060(2), b = 7.1857(2), c = 9.0661(2) Angstrom]; (3) crystal symmetry monoclinic [space group P2(1)/c, a = 6.9376(9), b = 7.1306(12), c 8.5852(20) Angstrom, beta = 113.299(18)degrees]; (4) crystal symmetry orthorhombic [space group Pbcn, a = 9.0593(2), b 7.4410(1), c = 14.6697(2) Angstrom]; (5) crystal symmetry orthorhombic [space group Pbcn, a = 8.9727(1), b = 7.2354(1), c = 15.0444(2) Angstrom]; (6) crystal symmetry monoclinic [space group P2(1)/c, a = 6.9133(4), b = 7.9927(6), c = 8.2084(6)Angstrom, beta = 110.066(6)degrees]. N-TREOR 2004-41 Cordier, S Roisnel, T Poulain, M TSynthesis and characterization of the novel Nb3O5F5 niobium oxyfluoride: the term n=3 of the NbnO(2n-1)F(n+2) series JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 3119-3126. The solid-state synthesis of the oxyfluoride Nb3O5F5, its crystal structure determined from X-ray powder diffraction data as well as some physical characterizations, are reported. Nb3O5F5 constitutes the term n = 3 of the NbnO2n-1Fn+2 series related to the Dion-Jacobson phases. It crystallizes, at room temperature, in the tetragonal system (space group I4/mmm (no. 139); Z = 4; a = 3.9135(1) Angstrom, c = 24.2111(2) Angstrom, and V = 370.80(Angstrom(3)) The crystal structure appears to be an in-between of the three-dimensional network of NbO2F and the two-dimensional packing of NbOF3 (term n = 1 of the NbnO2n-1Fn+2 series). This layered structure consists of slabs made of three Nb(O2F)(6) corner-linked octahedra in thickness (n = 3) shifted one from another by a (1/2a + 1/2b)/transiation. Oxygen and fluorine atoms are randomly distributed over all the ligand sites. N-TREOR, DICVOL 2004-42 Rukiah, M Lefebvre, J Hernandez, O van Beek, W Serpellon, M Ab initio structure determination of the Gamma form of D-sorbitol (D-glucitol) by powder synchrotron X-ray diffraction JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 766-772. A high-resolution powder synchrotron X-ray diffraction pattern of the. form of D-sorbitol has been recorded at 293 K on the BM1B beamline at the ESRF ( Grenoble). The starting model of the structure was found by Monte Carlo simulated annealing. The final structure was obtained through Rietveld refinements performed with soft restraints on interatomic bond lengths and angles. The symmetry is orthorhombic, space group P2(1)2(1)2, with 12 molecules within the cell [a = 24.3012 ( 2), b = 20.5726 ( 2), c = 4.8672 ( 1) Angstrom, V = 2433.30 ( 3) Angstrom(3), Z' = 3, 36 non-H independent atoms]. Crystalline cohesion between neighbouring molecules is achieved by three networks of O-H...O hydrogen bonds. The width of the Bragg peaks is interpreted through a microstructural approach in terms of anisotropic strain effects. N-TREOR 2004-43 Yang, QB Wang, PL Li, YX Yin, QR Werner, PE Moliterni, AGG Cheng, YB On the superstructure of KTiO2(OH) ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 227-230. The superstructure of potassium titanate, KTiO2(OH), prepared by hydrothermal synthesis has been determined from synchrotron powder diffraction data. It is shown that the unit cell of the superstructure is rhombohedral: a = 11.13848 Angstrom, alpha = 52.7336degrees. The structure has been determined and refined in space group R (3) over barc to R-F = 0.074. The distribution of hydrogen atoms as hydroxy groups can be explained from the crystal structure described by the supercell. N-TREOR 2004-44 Mahe, N Bataille, T Synthesis, crystal structure from single-crystal and powder x-ray diffraction data, and thermal behavior of mixed potassium lanthanide squarates: Thermal transformations of layered [Ln(H2O)(6)]K(H2C4O4)(C4O4)(2) into pillared LnK(C4O4)2 (Ln = Y, La, Gd, Er) INORGANIC CHEMISTRY 43, 2004, 8379-8386. A new series of mixed potassium and rare-earth squarates, [Ln(H2O)(6)]K(H2C4O4)(C4O4)(2) (Ln = Y, La, Gd, Er), has been synthesized and structurally characterized from single-crystal X-ray diffraction and spectroscopic analyses. The yttrium-based compound crystallizes with a monoclinic symmetry, space group C2/c [a = 8.3341(2) Angstrom, b = 37.7094(g) Angstrom, c = 11.7195(3) Angstrom, beta = 90.3959(9)degrees, V = 3683.1(2) Angstrom(3), Z = 8]. The structure is built from layers maintained together via hydrogen bonds. Within a layer, squarate ligands act as linkers between lanthanide and potassium cations. The thermal decomposition of the precursors has been studied by powder thermodiffractometry and thermal analyses. It is shown that crystalline intermediate phases are formed during the degradation. Among them, unprecedented mixed anhydrous squarates, LnK(C4O4)(2), could be isolated. The crystal structure of the Y compound has been solved ab initio from X-ray powder diffraction data, using direct-space methods [a = 6.2010(5) Angstrom, c = 11.639(l) Angstrom, V = 447.55 Angstrom(3), Z = 2]. The structure consists of layers of edge-sharing YO8 and KO8 antiprisms, pillared by mu(8)-squarate groups. The end of the precursor decomposition is marked by the formation of cubic sesquioxides Ln(2)O(3), including lanthanum oxide. DICVOL 2004-45 Zhang, Y Li, YD Red photoluminescence and crystal structure of Sr3Y2(BO3)(4) JOURNAL OF ALLOYS AND COMPOUNDS 384, 2004, 88-92. The crystal structure of a new compound Sr(3)y(2)(BO3)(4) has been determined from powder X-ray diffraction data by means of the Rietveld method. The structure can be described as being made up of isolated triangles, strontium-oxygen polyhedra, and yttrium-oxygen polyhedra. The yttrium atom has eight-fold coordination. The strontium atoms have 10-, 9- and 8-fold coordination in a covalent matrix. Sr(3)y(2)(BO3)(4):Eu phosphor exhibits a strong red emission around 615 nm because Eu3+ ion locates at a non-centrosymmetric site in the host lattice. In particular, the compound Sr-3(Y0.9Eu0.1)(2)(BO3)(4) has the strongest emission intensity. DICVOL 2004-46 Li, YQ de With, G Hintzen, H Synthesis, structure, and luminescence properties of Eu2+ and Ce3+ activated BaYSi4N7 JOURNAL OF ALLOYS AND COMPOUNDS 385, 2004, 1-11. BaYSi4N7 and its phosphors activated with Eu2+ and Ce3+ were synthesized by solid-state reaction at 1400-1650 degreesC under nitrogen mixed with hydrogen atmosphere. The crystal structure of BaYSi4N7 was solved by direct methods and refined by the Rietveld method from powder X-ray diffraction data. BaYSi4N7 crystallizes in the hexagonal space group P6(3)mc (No.186), with a = 6.0550 (2) Angstrom, c = 9.8567 (1) Angstrom, V = 312.96 (2) Angstrom(3). and Z = 2. which is isotypic with BaYbSi4N7. The photoluminescence properties have been studied for the solid solutions of Ba1-xEuxYSi4N7 (x = 0-0.4) and BaY1-xCexSi4N7 (x = 0-0.1) at room temperature. Eu2+-doped BaYSi4N7 gives a broad green emission band centered between 503 and 527 nm depending on the Eu2+ concentration. The Eu2+ emission band shows a red-shift formulation with increasing Eu2+ concentration mainly caused by the change of the crystal field strength and Stokes shift. Concentration quenching of Eu2+ emission is observed for x = 0.05 due to energy transfer between Eu2+ ions by electric dipole-dipole interactions with a critical interaction distance of about 20 Angstrom. Ce3+-doped BaYSi4N7 exhibits a bright blue emission band with a maximum at about 417 nm, which is independent of Ce3+ concentration. This is ascribed to a lower solubility of Ce3+ ions in BaYSi4N7 lattice as shown by X-ray powder diffraction analysis. DICVOL, direct methods 2004-47 Matsuda, R Kitaura, R Kitagawa, S Kubota, Y Kobayashi, TC Horike, S Takata, M Guest shape-responsive fitting of porous coordination polymer with shrinkable framework JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 126, 2004, 14063-14070. In situ synchrotron X-ray powder diffraction patterns of porous coordination polymers {[Cu-2-(pzdc)(2)(bpy)](.)G} have been measured (pzdc = pyrazine-2,3-dicarboxylate, bpy = 4,4'-bipyridine) (where G = H2O for CPL-2 superset of H2O, G = benzene for CPL-2 superset of benzene, and G = void for the apohost). The structures of apohost and CPL-2 superset of benzene were determined from Rietveld analysis. Adsorption of benzene in the channels induced a remarkable contraction in the crystal (b axis; 6.8%, volume; 4.9%), although the channels were occupied by the benzene molecules. This crystal transformation provides a new pore structure that is well suited for benzene molecules, and we denote it as a "shape-responsive fitting" transformation. This type of pore gives rise to a new guideline: frameworks can be composed of flexible motifs that are linked via strong bond and/or stiff motifs that are connected via weaker bonds. DICVOL 2004-48 Salamakha, PS Sologub, OL Rizzoli, C Hester, JR Stepien-Damm, J Goncalves, AP Lopes, EB Almeida, M Ternary RPt4B (R = La, Ce, Pr, Nd) compounds; structural and physical characterisation INTERMETALLICS 12, 2004, 1325-1334. The compounds RPt4B, with (R = La, Ce, Pr, Nd), were synthesized and their crystal structure was studied either by single crystal X-ray diffraction and/or by conventional and synchrotron X-ray powder diffraction. All four compounds of this family are isostructural and belong to the CeCo4B structure type. AC-susceptibility and magnetization studies show that: there is no magnetic ordering of the La compound down to 1.7 K; the Ce compound presents an antiferromagnetic-type-transition at 2.4 K; and both Pr and Nd compounds present a ferromagnetic-type transition at 4.2 and 4.9 K, respectively. Electrical resistivity studies show metallic behaviour for all compounds, the temperature dependence for the La compound being described by the Bloch Gruneisen relation. Thermopower studies as a function of temperature show that the thermopower is positive and small for these compounds, which is consistent with hole dominated metallic behaviour. DICVOL 2004-49 ???????? Kitaura, R Iwahori, F Matsuda, R Kitagawa, S Kubota, Y Takata, M Kobayashi, TC Rational design and crystal structure determination of a 3-D metal-organic jungle-gym-like open framework INORGANIC CHEMISTRY 43, 2004, 6522-6524. A new three-dimensional (3-D) jungle-gym-like open metal-organic framework has been synthesized from a two-dimensional (2-D) layer compound using a heterogeneous pillar insertion reaction. Both the starting 2-D layer and the resulting 3-D open compounds have been characterized using X-ray crystallography. DICVOL 2004-50 Johnston, A Florence, AJ Shankland, K Markvardsen, A Shankland, N Steele, G Cosgrove, SD Powder study of N-[2-(4-hydroxy-2-oxo-2,3-dihydro-1,3-benzothiazol-7-yl)ethyl]-3-[2-(2-n aphthalen-1-ylethoxy)ethylsulfonyl]propylaminium benzoate ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 60, 2004, O1751-O1753. The crystal structure of the title compound, C26H31N2O5S2+.-C7O2H5-, also known as AR-C69457CC, was solved by simulated annealing from laboratory X-ray powder diffraction data collected at room temperature to 2.1 Angstrom resolution. Subsequent Rietveld refinement yielded an R-wp of 0.038 and site-occupancy factors for the disordered anion components of 0.5. DICVOL, Simulated annealing 2004-51 Grzechnik, A Dmitriev, V Weber, HP Gesland, JY van Smaalen, S LiSrAlF6 with the LiBaCrF6-type structure JOURNAL OF PHYSICS-CONDENSED MATTER 16, 2004, 3005-3013. The crystal structure of LiSrAlF6-III (P2(1)/c, Z = 4) occurring above 3.0 GPa at room temperature was studied with synchrotron angle-dispersive x-ray powder diffraction in a diamond anvil cell. It was solved by combining a global optimization and a topological analysis with the Rietveld method using rigid-body AlF6 geometrical constraints. LiSrAlF6-III, related to LiBaCrF6 (P2(1)/c, Z = 4), is built of deformed SrF12 icosahedra within a three-dimensional framework of corner-sharing distorted AlF6 octahedra and LiF4 tetrahedra, whereas the low-pressure phases I (P (3) over bar 1c, Z = 2) and II (P2(1)/c, Z = 4) have cations exclusively in distorted octahedral coordinations. The pressure-induced changes of the coordination polyhedra in the series LiSrAlF6-I, LiSrAlF6-II to LiSrAlF6-III are similar to the differences in coordination polyhedra due to the increase of the ionic radii of the Sr2+ and Ba2+ cations in LiSrAlF6-I and LiBaM"F-6 (M" = At, Ga, Cr, V, Fe, or Ti) at ambient conditions. These observations are discussed on the basis of the high-pressure high-temperature systematics in AB(2)X(6) compounds. DICVOL 2004-52 Serre, C Millange, F Surble, S Greneche, JM Ferey, G Synthesis, characterization, and properties of an open-framework iron(III) dicarboxylate: MIL-85 or (Fe2O)-O-III{O2C-CH3}(2){O2C-C6H4-CO2}center dot 2CH(3)OH CHEMISTRY OF MATERIALS 16, 2004, 2706-2711. A new three-dimensional iron(III) dicarboxylate, MIL-85 or (Fe2O)-O-III{O2C-CH3}2{O2C- C6H4-CO2}.2CH(3)OH, has been obtained under solvothermal conditions, and its structure was determined using X-ray powder diffraction data. Its chiral framework is built up from helical chains of iron(III) octahedra linked through terephthalate dianions. This creates a three-dimensional structure with an array of 1-D small-pore channels filled with free and bound methanol moieties. The thermal behavior has been investigated using TGA, and X-ray thermodiffractometry indicates that MIL-85 is stable up to 275 degreesC with a fully reversible departure of solvent process. When the free and bound solvent molecules are removed, a nanoporous solid with a Langmuir surface area of 110 m(2)/g is obtained. Mossbauer spectrometry confirms the presence of high-spin-state Fe3+ within the structure and a change in the iron environment upon solvent departure. Finally, one can conclude from magnetic data that MIL-85 exhibits a frustrated magnetic behavior in the low-temperature range. Crystal data for MIL-85: hexagonal space group P6(1) (no. 169) with alpha = 11.045 (1) Angstrom, c = 18.823 (1) Angstrom, and Z = 6. DICVOL 2004-53 Kaduk, JA Crystal structure of guaifenesin, 3-(2-methoxyphenoxy)-1,2-propanediol POWDER DIFFRACTION 19, 2004, 127-132. The crystal structure of the common expectorant guaifenesin, 3-(2-methoxyphenoxy)-1, 2-propanediol (C10H14O4) was solved by applying Monte Carlo simulated annealing techniques to synchrotron powder data, and refined using the Rietveld method. Initial structure solutions yielded an unreasonable conformation, and an unacceptable refinement. Quantum chemical geometry optimizations were used to identify the correct conformation. Guaifenesin crystallizes in the orthorhombic space group P2(1)2(1)2(1) (#19), with a=7.65705(7), b=25.67020(24), c=4.97966(4) Angstrom, V=978.79(2) Angstrom(3), and Z=4. Both hydroxyl groups act as hydrogen bond donors and acceptors, resulting in the formation of a two-dimensional network of strong hydrogen bonds in the ac plane. The solid state conformation is similar to4 kcal/mol higher in energy than the minimum-energy conformation of an isolated molecule, but the formation of the hydrogen bonds results in an energy gain of similar to100 kcal/mol. Knowledge of the crystal structure permits quantitative phase analysis of guaifenesin-containing pharmaceuticals (such as Duratuss GP 120-1200) by the Rietveld method. DICVOL 2004-54 Audebrand, N Jeanneau, E Bataille, T Raite, S Louer, D A family of microporous mixed oxalates with isotypic-framework structures based on eight-coordinate metals SOLID STATE SCIENCES 6, 2004, 579-591. Structural relationships between mixed oxalates with crystal structures consisting of isotypic anionic frameworks [MM'(C2O4)(4)](2-) built from dodecahedrally coordinated M and M' metals, with counter cations located in tunnels, are described. The principles of a predictive structural derivation, based on the YK(C2O4)(2)(.)4H(2)O structure type, is presented. Four new phases with isotypic frameworks that conform to the classification and to a proposed empirical six-valence-sum rule are reported. The new oxalates have been synthesised from mild chemistry and their crystal structures have been determined from single-crystal or powder diffraction data. Crystal data for the new phases are: CdZrSr(C2O4)(4)(.)6H(2)O, S.G. I (4) over bar m2, a = 11.2362(4) Angstrom, c = 8.6084(3) Angstrom, Z = 2; InK(C2O4)(2)(.)4H(2)O, S.G. I4(1)/a, a = 11.0549(3) Angstrom, c = 8.9735(3) Angstrom, Z = 4; YRb(C2O4)(2)(.)4H(2)O, S.G. I4(1)/a, a = 11.4569(3) Angstrom, c = 9.1502(4) Angstrom, Z = 4; Ca2Zr(C2O4)(4)(.)5.5H(2)O, S.G. I (4) over bar m2, a = 11.2558(2) Angstrom, c = 8.4288(2) Angstrom, Z = 2. The open-framework structures of all phases can be described on the basis of building walls made of mixed dodecahedra MO8 and M'O-8, connected through bichelating oxalate groups. The third element is located in channels with an elliptic cross-section. The thermal behaviour of all phases is studied from thermogravimetry and thermodiffractometry. It is shown that the dehydration process is somewhat related to the structure features and depends on the valence of the counter cation. In all cases, zeolite-type properties involving weakly bonded water molecules are pointed out. DICVOL 2004-55 Mora, AJ Delgado, GE Pineda, C Tinoco, T Synthesis and structural study of the AgIn5Te8 compound by X-ray powder diffraction PHYSICA STATUS SOLIDI A-APPLIED RESEARCH 201, 2004, 1477-1483. The AgIn5Te8 compound was synthesized by the melt and annealing technique and its structure was refined from X-ray powder diffraction pattern using the Rietveld method. AgIn5Te8 crystallizes in the tetragonal space group R (4) over bar 2m (N-o 111), Z = 1, with a = 6.1952(2) Angstrom, c = 12.419(4) Angstrom, V = 476.7(2) Angstrom(3). The refinement of 23 instrumental and structural parameters led to R-p = 8.2%, R-wp = 11.6%, R-exp = 6.8% and S = 1.7; R-B = 11.2% for 5501 step intensities and 253 independent reflections. The structure is characterized by a double alternation of selenide-metal planes according to the In-2-Te-1-In-1-Te-2-Ag-Te-2-In-1-Te-1-In-2 sequence. DICVOL 2004-56 Wu, L Wang, C Chen, XL Li, XZ Xu, YP Cao, YG Ab initio structure determination of new compound Li4CaB2O6 JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 1847-1851. A new compound, Li(4)WaB(2)O(6), has been synthesized by solid-state reaction and its structure has been determined from powder X-ray diffraction data by direct methods. The refinement was carried out using the Rietveld methods and the final refinement converged with R-p = 10.4% R-wp = 14.2%, R-exp = 4.97%. This compound belongs to the orthorhombic space group Pnnm, with lattice parameters a 9.24036(9) Angstrom, b = 8.09482(7) Angstrom, and c = 3.48162(4) Angstrom. Fundamental building units are isolated [BO3](3-) anionic groups, which are all parallel to the a-b plane stacked along the c-axis. The Ca atoms are six-coordinated by the O atoms to form octahedral coordination polyhedra, which are joined together through edges along the c-axis, forming infinitely long three-dimensional chains. The Li atoms have a four-fold and a five-fold coordination with O atoms that lead to complex Li-O-Li chains that also extend along the c-axis. The infrared spectrum of Li4CaB2O6 was also studied, which is consistent with the crystallographic study. DICVOL 2004-57 Li, XJ Kobayashi, T Zhang, FX Kimoto, K Sekine, T A new high-pressure phase of LiAlO2 JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 1939-1943. A new high-pressure phase of LiAlO2 has been recovered through a shock recovery technique at pressures above 9 GPa. This new phase has been refined as a tetragonal structure with lattice parameters of a = 0.38866(8) nm and c = 0.83001(18) nm. Its calculated density is 3.51 g/cm(3). about 34% denser than gamma-LiAlO2. The aluminum and lithium cations in this new phase are six-fold coordinated, as in alpha-LiAlO2, and the structure of this new phase is similar to tetragonal LiFeO2. This new high-pressure phase is stable at temperatures up to 773 K. DICVOL 2004-58 Devi, RN Wormald, P Cox, PA Wright, PA Novel pillared aluminum ethylene diphosphonate displaying reversible dehydration-rehydration behavior CHEMISTRY OF MATERIALS 16, 2004, 2229-2237. The novel aluminum ethylene diphosphonate Al-2(OH)(2)(H2O)(2)(O3PCH2CH2PO3) has been synthesized hydrothermally.. It crystallizes in the triclinic space group (P (1) over bar; a = 8.5977(10), b = 7.0499(3), c = 9.5290(4) Angstrom; alpha = 89.997(21), beta = 104.321(8), gamma = 114.225(11)degrees; V = 506.98(8)Angstrom(3)) with aluminophosphonate layers similar to those found in Al(OH)(H2O)CH3PO3 linked via ethylene (-CH2CH2-) groups. The solid loses water upon heating in two steps, the first at 100 degreesC and the second at 360 degreesC. The first water loss leaves a crystalline solid with a framework structure of Al-2(OH)(2)(O3PCH2CH2PO3) closely related to that of the parent (C2/ c; a = 15.3723(21), b = 6.7613(8), c = 9.7374(13) Angstrom; beta = 102.392(9)degrees; V = 988.4438 Angstrom(3)) whereas the second water loss results in major loss of crystallinity. X-ray powder diffraction has been used to determine and refine the structures of the parent and intermediate dehydrated phases. The main structural difference is the loss of one water molecule bound to aluminum, which changes the metal cation's coordination from octahedral to distorted square planar. The as-prepared and dehydrated samples have been simulated computationally. The transformation has been monitored by in-situ Al-27 MAS NMR spectroscopy; octahedral aluminum (delta(iso) = -7.1 ppm; asymmetry parameter, eta = 1.0; quadrupolar coupling constant, QCC = 5.4 MHz) is converted to 5-fold coordinated aluminum (delta(iso) = 20.7 ppm; eta = 0; QCC = 5.8 MHz) by heating at 130 degreesC for 1 h. The process is fully reversible. DICVOL 2004-59 Serre, C Millange, F Thouvenot, C Gardant, N Pelle, F Ferey, G Synthesis, characterisation and luminescent properties of a new three-dimensional lanthanide trimesate: M((C6H3)-(CO2)(3)) (M = Y, Ln) or MIL-78 JOURNAL OF MATERIALS CHEMISTRY 14, 2004, 1540-1543. A new three-dimensional europium-doped yttrium 1,3,5-benzenetricarboxylate has been obtained under hydrothermal conditions. The structure of MIL-78(Y, Eu) or Y1-xEux((C6H3)-(CO2)(3)) (x similar to 0.024) has been solved from X-ray powder diffraction data (a = 6.941(1) Angstrom, b similar to 14.700(2) Angstrom, c = 8.488(1) Angstrom, beta = 107.73(1) degrees, V = 824.9(4) Angstrom(3), space group C2/m (no. 12)). Its structure is built up from chains of edged-sharing eight-coordinated monocapped square antiprism polyhedra and trimesate anions, creating a three-dimensional structure. The same structure is formed by replacing yttrium by a rare-earth element. The thermal behaviour of MIL-78(Y, Eu) has been investigated using TGA and X-ray thermodiffractometry and indicates that MIL-78(Y, Eu) is stable up to 450 degreesC. The study of the optical properties of samples doped with different rare-earths reveals strong fluorescence under VUV radiation. DICVOL 2004-60 Cerny, R Renaudin, G Favre-Nicolin, V Hlukhyy, V Pottgen, R Mg1+xIr1-x (x=0, 0.037 and 0.054), a binary intermetallic compound with a new orthorhombic structure type determined from powder and single-crystal X-ray diffraction ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 60, 2004, 272-281. The new binary compound Mg1 + xIr1-x (x = 0-0.054) was prepared by melting the elements in the Mg:Ir ratio 2:3 in a sealed tantalum tube under an argon atmosphere in an induction furnace (single crystals) or by annealing cold-pressed pellets of the starting composition Mg:Ir 1:1 in an autoclave under an argon atmosphere (powder sample). The structure was independently solved from high-resolution synchrotron powder and single-crystal X-ray data: Pearson symbol oC304, space group Cmca, lattice parameters from synchrotron powder data a = 18.46948 (6), b = 16.17450 (5), c = 16.82131 (5) Angstrom. Mg1-xIr1-x is a topologically close-packed phase, containing 13 Ir and 12 Mg atoms in the asymmetric unit, and has a narrow homogeneity range. Nearly all the atoms have Frank-Kasper-related coordination polyhedra, with the exception of two Ir atoms, and this compound contains the shortest Ir-Ir distances ever observed. The solution of a rather complex crystal structure from powder diffraction, which was fully confirmed by the single-crystal method, shows the power of powder diffraction in combination with the high-resolution data and the global optimization method. DICVOL 2004-61 Li, XZ Chen, XL Wu, L Cao, YG Zhou, T Xu, Y Ba3YB3O9: phase transition and crystal structure JOURNAL OF ALLOYS AND COMPOUNDS 370, 2004, 53-58. A new modification of the compound Ba3YB3O9, beta phase, has been attained through solid phase transition from alpha phase at 1125-1134degreesC. beta-Ba(3)yB(3)O(9) crystallizes in the hexagonal space group R3 with cell parameters a = 13.0529(8) (A) over circle, c = 9.5359(9) (A) over circle. The crystal structure of alpha-Ba3YB3O9 has been determined from powder X-ray diffraction (XRD) data. The refinement was carried out using the Rietveld methods and the final refinement converged with R-p = 8.8%, and R-wp = 11.8% with R-exp = 5.65%. In its structure, the isolated [BO3](3-) anionic groups are parallel to each other and distributed layer upon layer along the c-axis. The Y atoms are six-coordinated by the O atoms to form octahedra. The result of IR spectrum confirmed the existence of [BO3](3-) triangular groups. DICVOL 2004-62 Zhang, Y Li, YD Red photoluminescence properties and crystal structure of sodium rare earth oxyborate JOURNAL OF ALLOYS AND COMPOUNDS 370, 2004, 99-103. The subsolidus phase relations of the system Y2O3-Na2O-B2O3 are reported. There are seven binary compounds and two ternary compounds in this system. A new ternary compound Na2Y2B2O7 is identified. The structure has been determined for the compound Na2Y2B2O7 from powder X-ray diffraction. The lattice constants of P2(1)/c for the compound Na2Y2B2O7 are a = 10.5993 (1) (A) over circle, b = 6.2311 (1) (A) over circle, c = 10.2247(1) (A) over circle, beta = 117.756(1)degrees and z = 4. The structure can be described as being made up of isolated BO3 triangles and YO8 polyhedra. The photoluminescence properties of Eu ion-doped Na2Y2B2O7 and Na3Y(BO3)(2) show strong red-emission of the D-5(0)-F-7(2) transitions at 611 and 615 nm, respectively. The results of emission spectra are in good agreement with the crystallographic study. The relationship between Eu ion content and emission intensity is analyzed too. DICVOL 2004-63 ?? Serre, C Pelle, F Gardant, N Ferey, G Synthesis and characterization of MIL-79 and MIL-80: Two new luminescent open-framework rare-earth dicarboxylates with unusual 1D inorganic subnetworks CHEMISTRY OF MATERIALS 16, 2004, 1177-1182. Two new three-dimensional europium(III) dicarboxylates, MIL-79 or EU5(III)(OH)(9)(H2O)(6)-(O2C-C2H2-CO2)(3)(.)9.5H(2)O, and MIL-80 or EU4III(OH)(4)(H2O)(5)(O2C-C2H2-CO2)(4)(.)4H(2)O, have been obtained under hydrothermal conditions. Both structures, which have been determined using either X-ray powder or single-crystal diffraction data, are built-up from unusual complex chains made from clusters of eight-, nine-, and ten-coordinated europium(III) polyhedra linked through fumarate and maleate dianions. This creates three-dimensional structures with either I-D large elongated pore channels (MIL-79) or cages (MIL-80) filled in both cases with free water molecules which interact with terminal water molecules or apical oxygen atoms from the carboxylates. The thermal behavior of MIL-79 has been investigated using TGA and X-ray thermodiffractometry and reveals that its dehydration leads to an irreversible pore contraction. Study of the luminescence properties of the yttrium(III) form of MIL-79 doped with europium(III) reveals a significant red-emission upon VUV radiation. Crystal data for MIL-79: monoclinic space group C2/m with a = 25.954(1) Angstrom, by = 11.014(1) Angstrom, c = 13.247(1) Angstrom, beta = 119.162(1)degrees, and Z = 4. Crystal data for MIL-80: triclinic space group P (1) over bar with a = 10.5770(2) Angstrom, b = 10.6164(2) Angstrom, c = 14.9403(3) Angstrom, alpha = 91.624(1)degrees, beta = 91.120(1)degrees, gamma = 113.892(1)degrees, and Z = 2. DICVOL 2004-64 Couhorn, U Dronskowski, R Alkali-metal meta-hydroxyphenolates: Syntheses and crystal structures from powder X-ray diffraction ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 630, 2004, 427-433. M[M-C6H4O(OH)] (M = Li-Cs) have been obtained as highly air- and moisture-sensitive powders from reaction mixtures of the appropriate alkali metals and resorcinol in thf. Both the potassium and rubidium compounds were structurally characterized by means of powder X-ray diffraction using the Simulated Annealing method and the Rietveld profile refinement technique including C-C/C-O bond distance and C-C-C angle restraints. K[m-C6H4O(OH)] (orthorhombic P2(1)2(1)2(1)) forms infinite alternating chains of meta-hydroxyphenolate anions connected by K-O bonds and short charge-assisted hydrogen bonds, thereby generating a three-dimensional network of corrugated layers similar to the structure of pure resorcinol. The potassium cations are surrounded by a triangle of oxygen and, moreover, coordinated by six adjacent phenylene rings to form a distorted octahedron. The complex crystal structure of Rb[m-C6H4O(OH)] (monoclinic Pa) is characterized by layers of hydrogen-bonded meta-hydroxyphenolate triple units separated by corrugated rubidium layers. The three crystallographically different Rb atoms are coordinated by three, four, and five oxygens with irregular polyhedra, and the rubidiums are also involved in further electrostatic interactions by up to eight phenylene rings. DICVOL 2004-65 Guillou, N Livage, C van Beek, W Ferey, G Ab initio determination of a new complex structure (55 non-hydrogen atoms) from synchrotron powder data: An uncommon nickel succinate, Ni-7(C4H4O4)(4)(OH)(6)(H2O)(3)center dot 7H(2)O EUROPEAN POWDER DIFFRACTION EPDIC 8 443-4, 2004, 333-336. Ni-7(C4H4O4)(4)(OH)(6)(H2O)(3)(.)7H(2)O, a new layered nickel(II) succinate, was prepared hydrothermally (180degreesC, 48 h, autogenous pressure) from a 1:1.5:4.1:120 mixture of nickel (II) chloride hexahydrate, succinic acid, potassium hydroxide and water. It crystallizes in the monoclinic system (space group P2(1)/c, Z = 4) with the following parameters a = 7.8597(1) Angstrom, b = 18.8154(3) Angstrom, c = 23.4377(4) Angstrom, beta= 92.0288(9)degrees, and V= 3463.9(2) Angstrom(3). Its structure, which contains 55 non-hydrogen atoms, was solved ab initio from synchrotron powder diffraction data. It can be described from hybrid organic-inorganic layers, constructed from nickel oxide corrugated chains. These chains are built up from NiO6 hexameric units connected via a seventh octahedron. Half of the succinates decorate the chains, and the others connect them to form the layers. The three dimensional arrangement is ensured by hydrogen bonds directly between two adjacent layers and via free water molecules. DICVOL 2004-66 Zaske, L Perrin, MA Daiguebonne, C Guillou, O Docetaxel (Taxotere (R) Trihydrate) forms: Crystal structure determination from XRPD & XRSCD data EUROPEAN POWDER DIFFRACTION EPDIC 8, 443-4, 2004, 411-414. Docetaxel (form A), a stoichiometric hydrate containing three water molecules per molecule of drug substance (Taxoteree), is thermodynamically stable under ambient conditions of pressure, temperature and relative humidity. In order to gain a better understanding of docetaxel system at the atomic scale a structural study was performed. Due to strong anisotropy of crystals (thin plates), the crystal structure of docetaxel (29 degrees of freedom) was solved and refined using high resolution XRPD data applying an ab initio direct space method. In parallel, an in-depth crystal growth study was carried out until single crystals suitable for XRSCD structural resolution were obtained: surprisingly, a new polymorph of docetaxel, called form B, was isolated. DICVOL 2004-67 Albesa-Jove, D Kariuki, BM Kitchin, SJ Grice, L Cheung, EY Harris, KDM Challenges in direct-space structure determination from powder diffraction data: A molecular material with four independent molecules in the asymmetric unit CHEMPHYSCHEM 5, 2004, 414-418. DICVOL, GENETIC ALGORITHM 2004-68 Grzechnik, A Dmitriev, V Weber, HP Gesland, JY van Smaalen, S The crystal structures of pressure-induced LiSrAlF6-II and LiCaAlF6-II JOURNAL OF PHYSICS-CONDENSED MATTER 16, 2004, 1033-1043. The crystal structures of LiCaAlF6-II and LiSrAlF6-II (both P2(1)/c, Z = 4) occurring at high pressures and room temperature were studied with synchrotron angle-dispersive x-ray powder diffraction in diamond anvil cells. The structure of LiSrAlF6-II stable between 1.6 and 3.0 GPa was solved with a global optimisation algorithm and group theory considerations, and refined with the Rietveld method in the rigid-body approximation. It is a distorted variant of the ambient pressure polymorph (LiSrAlF6-I, , Z = 2), in which each cation occupies a deformed octahedral site. LiCaAlF6 transforms to this monoclinic polymorph II above about 7 GPa. The differences in the high-pressure behaviours of LiCaAlF6 and LiSrAlF6 are discussed by considering the ionic radii. DICVOL 2004-69 Muangsin, N Prajuabsook, M Chimsook, P Chantarasiri, N Siraleartmukul, K Chaichit, N Hannongbua, S Structure determination of diclofenac in a diclofenac-containing chitosan matrix using conventional X-ray powder diffraction data JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 288-294. The structure determination of diclofenac embedded in a diclofenac-containing chitosan matrix using conventional X-ray powder diffraction data is demonstrated. It reveals that sodium diclofenac, the starting material in the preparation of a controlled-release diclofenac-containing chitosan matrix, changes to diclofenac acid in space group C2/c in the matrix. Simple methods were employed for handling the sample to obtain X-ray powder diffraction data of sufficiently high quality for the determination of the crystal structure of diclofenac embedded in chitosan. These involved grinding and sieving several times through a micro-mesh sieve to obtain a suitable particle size and a uniformly spherical particle shape. A traditional technique for structure solution from X-ray powder diffraction data was applied. The X-ray diffraction intensities were extracted using Le Bail's method. The structure was solved by direct methods from the extracted powder data and refined using the Rietveld method. For comparison, the single-crystal structure of the same drug was also determined. The result shows that the crystal structure solved from conventional X-ray powder diffraction data is in good agreement with that of the single crystal. The deviations of the differences in bond lengths and angles are of the order of 0.030 Angstrom and 0.639degrees, respectively. DICVOL 2004-70 Nowell, H Attfield, JP X-Ray and neutron powder diffraction studies of the crystal structure of vitamin K-3 NEW JOURNAL OF CHEMISTRY 28, 2004, 406-411. The previously unknown structure of vitamin K-3 (menadione, 2-methyl-1,4-naphthoquinone, C11H8O2), a synthetic compound from which it is possible to derive the naturally occurring K vitamins, has been solved from X-ray powder diffraction data. Solution was achieved using simulated annealing and restrained Rietveld refinement, using restraints derived from similar known structures. Further refinement has been carried out using neutron diffraction data; this confirmed the molecular packing and allowed further insight into the structural detail with regard to methyl group orientation, thus allowing the proposal of an extensive C - H...O hydrogen bonding scheme by reference to comparable known structures. The crystal structure consists of chains of molecules lying head-to-tail. This study may aid the understanding of the biological activity of vitamin K. DICVOL 2004-71 Li, XZ Chen, XL Jian, JK Wu, L Xu, YP Cao, YG Thermal stability and crystal structure of beta-Ba3YB3O9 JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 216-220 A new compound, beta-Ba3YB3O9, has been attained through solid phase transition from alpha-Ba3YB3O9 at high temperatures. Differential thermal analysis (DTA) revealed the phase transition at about 1120degreesC, the melting temperature at about 1253degreesC. Its crystal structure has been determined from powder X-ray diffraction data. The refinement was carried out using the Rietveld method and the final refinement converged with R-p = 10.5% and R-wp = 13.7%. This compound belongs to the hexagonal space group R-3, with lattice parameters a = 13.0441(1) Angstrom and c = 9.5291(1) Angstrom. There are 6 formulas per unit cell and 7 atoms in the asymmetric unit. The structure of beta-Ba3YB3O9 is built up from Ba(Y)O-8, BaO6 and YB6O18 units formed by one YO6 octahedron and six BO3 triangles with shared O atoms. DICVOL 2004-72 Graham, D Kennedy, AR McHugh, CJ Smith, WE David, WIF Shankland, K Shankland, N The crystal structures of three primary products from the selective reduction of 2,4,6-trinitrotoluene NEW JOURNAL OF CHEMISTRY 28, 2004, 161-165 The crystal structures of three primary products from the selective reduction of 2,4,6-trinitrotoluene (TNT) have been determined by synchrotron X-ray powder diffraction (2-amino-4,6-dinitrotoluene) and single crystal X-ray diffraction (4-amino-2,6-dinitrotoluene and 2-hydroxyamino-4,6-dinitrotoluene). The molecular structure of 2-amino-4,6-dinitrotoluene, including rotational disorder of the 6-nitro group, was subsequently detailed to a higher resolution by a single-crystal analysis. In contrast to the known structures of TNT, the crystal structures of these amino species are dominated by hydrogen-bonded sheets connected via ring stacking, whilst that of 2-hydroxyamino-4,6-dinitrotoluene is dominated by the dual hydrogen-bonding acceptor/donator role of the hydroxyamine group. DICVOL, Sync 2004-73 Kavecansky, V Mihalik, M Mitroova, Z Lukacova, M Neutron diffraction study of crystal and magnetic structure of Dy[Fe(CN)(6)].4D(2)O CZECHOSLOVAK JOURNAL OF PHYSICS, 54, suppl D, part 2, 2004, D451-D574. We present an analysis of the powder neutron diffraction patterns taken from the Dy[Fe(CN)(6)]. 4D(2)O at room temperature and in the temperature range 1.6 - 40 K. The deuterium positions were localized by means of combination of direct and reciprocal space methods and crystal structure of the compound was refined using the Rietveld method. The knowledge of the complete crystal structure, including the deuterium atoms positions, enables further investigation of magnetic structure of these types of materials from the neutron diffraction experiments. The investigated phase was found to order magnetically bellow 2.8 K. The diffraction patterns taken at temperatures 1.76 K - 9.63 K show gradual development of magnetic moment as temperature decreases. 2004-74 Baerlocher, C McCusker, LB Prokic, S Wessels, T Exploiting texture to estimate the relative intensities of overlapping reflections ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 803-812. Additional information about the relative intensities of reflections that overlap in a powder diffraction pattern can be obtained from a polycrystalline sample in which the crystallites are preferentially oriented. If the data are collected and analyzed appropriately, more single-crystal-like reflection intensities can be extracted, and thereby more complex structures solved. This 'texture method' was implemented initially in reflection mode and its power demonstrated with the solution of the 117-atom structure of the hi-h-silica zeolite UTD-1F However, the experiment required a minimum of 3 days of synchrotron beamtime per sample. In an attempt to reduce the amount of beamtime needed and to simplify the experiment itself, a transmission mode alternative using an area detector was developed. Details of the sample preparation, data collection and data analysis for both geometries are described. The solution of the structures of the aluminophosphates Mu-9 (R(3) over bar c, a = 14.0696(1) Angstrom, c = 42.3113(4) Angstrom) and AIPO-M (Pbca, a = 9.7493(1) Angstrom, b = 29.1668(2) Angstrom, c = 9.3528(1) Angstrom) using reflection and transmission mode data, respectively, are provided as examples of the method. 2004-75 Bataille, T Audebrand, N Boultif, A Louer, D Structure determination of thermal decomposition products from laboratory X-ray powder diffraction ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 881-891. Ab initio structure determination from powder diffraction data of compounds resulting from solid state transformations is still rather limited. Two major factors influence the stages of the structure elucidation of these solids, i.e. the lower precision in peak position for indexing and the strong line overlap for extracting integrated intensities. The present study deals with the consideration of these two problems for solving the crystal structure of two thermal-decomposition inorganic products, Nd(NO3)(3) (.) 4 H2O and Pb3O2(NO3)(2). The new features of DICVOL04, as zero shift refinement. a priori zero search and tolerance of spurious lines have been used for indexing, several phases obtained during the thermal treatment of neodymium nitrate hexahydrate. The crystal structures of Nd(NO3)(3) (.) 4 H2O and Pb3O2(NO3)(2) have been solved with the direct methods and the structure model of Pb3O(2)(NO3)(2) has been completed using a global optimisation approach. The monoclinic structure of neodymium nitrate tetrahydrate [a - 10.1744(4) Angstrom, b = 8.9716(5) Angstrom, c = 11.7295(5) Angstrom, beta = 97.384(4)degrees, V = 1061.80 Angstrom(3), S.G. P2(1)/c] is built from isolated ten-fold coordinated Nd polyhedra. The orthorhombic structure of lead oxide nitrate [a = 7.6034(4) Angstrom, b = 5.7691(4) Angstrom, c = 18.5817(9) Angstrom, V = 815.09 Angstrom(3), S.G. Pnma] is built from double chains of edge-sharing OPb4 tetrahedra connected by nitrate groups. In order to estimate the chance of solving crystal structure of nanocrystalline powdered compounds, a comparison of the efficiency of direct methods and direct-space approaches is made from powder diffraction patterns simulated for various crystallite sizes from the crystal structure of the decomposition product gamma-Zn2P2O7. 2004-76 Perchiazzi, N Ondrus, P Skala, R Ab initio X-ray powder structure determination of parascorodite, Fe(H2O)(2)AsO4 EUROPEAN JOURNAL OF MINERALOGY, 16, 2004, 1003-1007. The crystal structure of parascorodite, Fe(H2O)(2)AsO4, has been solved ab-initio from powder data. The mineral is trigonal, with space group P (3) over bar c1, Z = 6, a = 8.9232(2) Angstrom, c = 9.9296(3) Angstrom. The Rietveld refinement was led up to R-p = 4.5%. The structure is built up by the same coordination polyhedra found in its dimorph scorodite, namely slightly distorted Fe-centred octahedra and As-centred tetrahedra, but their connection lead to quite different crystal structures for the two polymorphs. Parascorodite structure can be described in terms of mixed octahedral-tetrahedral "columns" including Fe2 and As polyhedra, running along c, similar to those found in ferrinatrite and kaatialaite. These columns are interconnected in a threedimensional framework by the sharing of the O1 oxygen between [AsO4] tetrahedra and Fe1 octahedra, and by the strong hydrogen bond OW(...)O2. 2004-77 Golobic, A Skapin, SD Suvorov, D Meden, A Solving structural problems of ceramic materials CROATICA CHEMICA ACTA 77, 2004, 435-446. Methods for the crystal structure determination from powder diffraction data are reviewed with special emphasis on the application to technical ceramics. Experimental techniques using other than laboratory X-ray, such as synchrotron radiation, neutron and electron beams, are also described. As an illustrative example, the crystal structure determinations of compounds LaNbTiO6, La0.462Nb0.614Ti0.386O3 and La0.37Nb0.889Ti0.111O3 in the ternary system of La2O3-Nb2O5-TiO2 are reported. 2004-78 Garcia-Cuesta, MC Lozano, AM Melendez-Martinez, JJ Luna-Giles, F Ortiz, AL Gonzalez-Mendez, LM Cumbrera, FL Structure determination of nitrato-kappa O-bis[2-(2-pyridyl-kappa N)amino-5,6-dihydro-4H-1,3-thiazine-kappa N]copper(II) nitrate via molecular modelling coupled with X-ray powder diffractometry JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 993-999. The title copper(II) coordination compound, C18H22CuN8O6S2 {[Cu(NO3)( PyTz)(2)] NO3}, was synthesized in the form of small crystals unsuitable for structure determination by single-crystal X-ray diffractometry. It was therefore characterized by molecular modelling coupled with X-ray powder diffractometry [ monoclinic, space group P2(1)/n, a = 20.695 (7) Angstrom, b = 8.054 (2) Angstrom, c = 15.157 (4) Angstrom, beta = 112.09 (2)degrees and R-wp = 0.129]. The procedure used to resolve the structure followed direct space methods with a 'Monte Carlo/parallel tempering' search algorithm, where the starting configuration was obtained by means of molecular mechanics. A final refinement was performed with the Rietveld method. Bond distances, bond angles and torsion angles were compared with those of similar compounds deposited in the Cambridge Structural Database. 2004-79 Belik, AA Azuma, M Takano, M Lazoryak, BI SrF(e)2(PO4)(2): Ab initio structure determination with X-ray powder diffraction data and unusual magnetic properties CHEMISTRY OF MATERIALS 16, 2004, 4311-4318. Structure of SrFe2(PO4)(2) was solved ab initio from X-ray powder diffraction data (space group P2(1)/c (No. 14); Z = 4; a = 9.3647(2) c, b = 6.8518(l) Angstrom, c = 10.5367(2) Angstrom, and = 109.5140(8)degrees). It has almost linear tetrameric units Fe2-Fe1-Fe1-Fe2 which join with each other through common oxygen atoms creating a complicated two-dimensional network parallel to the bc plane. Specific heat measurements revealed two phase transitions at T-1 = 7.0 K and T-2 = 11.3 K in zero magnetic field. The phase transition at T-2 seems to be a structural phase transition. Magnetization measurements showed that, below T-1, SrFe2(PO4)(2) exhibits weak ferromagnetism and demonstrates clear ferromagnetic hysteresis loops. Above 15 K, Curie-Weiss behavior was observed with an effective magnetic moment of 5.23 muB per Fe2+ ion and Weiss constant of -18.9 K. Weak ferromagnetic properties below T-1 can be explained by canting of antiferromagnetically ordered spins. Several field-induced phase transitions were observed in SrFe2(PO4)(2) at low temperatures. 2004-80 Peschar, R Pop, MM De Ridder, DJA van Mechelen, JB Driessen, RAJ Schenk, H Crystal structures of 1,3-distearoyl-2-oleoylglycerol and cocoa butter in the beta(V) phase reveal the driving force behind the occurrence of fat bloom on chocolate JOURNAL OF PHYSICAL CHEMISTRY B 108, 2004, 15450-15453. On the basis of high-resolution synchrotron powder diffraction data, crystal structures have been solved for 1,3-distearoyl-2-oleoylglycerol, a major cis-mono-unsaturated triglyceride fraction of cocoa butter, and cocoa butter itself in the beta(V) phase. The latter implies that in fact a crystal structure model of chocolate in the beta(V) phase has been obtained. The results clarify the metastability of the beta(V) phase and explain why fat bloom may develop on beta(V)-type chocolate that has been stored at temperatures that are too high. 2004-81 ??? Ikeda, T Akiyama, Y Oumi, Y Kawai, A Mizukami, F The topotactic conversion of a novel layered silicate into a new framework zeolite ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 43, 2004, 4892-4896. 2004-82 ?????? Harvey, HG Herve, AC Hailes, HC Attfield, MP Synthesis, crystal structures, and modifications of novel framework gallium diphosphonates CHEMISTRY OF MATERIALS The framework gallium diphosphonates 16, 2004, 3756-3766. Ga-2[O3PC2H4PO3](H2O)(2)F-2.-2H(2)O (1) (triclinic, P1, a = 5.0432(2) Angstrom, b = 7.2468(3) Angstrom, c = 8.3499(4) Angstrom, alpha = 107.489(2)degrees, beta = 92.444(2)degrees, gamma = 109.338(2)degrees, Z =1) and Ga-2[O3PCH2(C6H4)CH2PO3](H2O)(2)F-2 (2) (triclinic, P1, a = 4. 9673(l) Angstrom, b = 7. 0898(2) Angstrom, c = 10. 1220(3) Angstrom, alpha = 92. 698(2)degrees, beta = 93.153(2)degrees, gamma = 109. 122(2)degrees, Z = 1) and the solid-solution series Ga-2{[O3PCH2(C6H4)CH2PO3](1-x)(HPO3)(2x)}(H2O)(2)F-2 (0 less than or equal to X less than or equal to 0. 146) x = 0.541 (3) and x = 0.144 Ga-2{[O3PCH2(C6H4)CH2PO3](0.853(6))(HPO3)(0.29(1))}(H2O)(2)F-2 (4) (triclinic, P1, a = 4.959(2) Angstrom, b = 7.078(2) Angstrom, c = 10.024(3) Angstrom,alpha = 92.404(5)degrees, beta = 92.955(5)degrees, gamma = 109.187(5)degrees, Z = 1) have been synthesized by solvothermal methods and their structures determined using X-ray diffraction data. All the materials contain linear chains of corner-sharing GaO4F2 octahedra that are linked by the diphosphonate groups to form framework structures. The channels of 1 are found to contain two water molecules per unit cell while those in 2 are too narrow to contain extraframework species. The apertures created in the phosphite-substituted derivatives of 2 (3 and 4) are shown, by crystallographic methods, to be considerably larger than those in 2 and, by thermogravimetric methods, to create more open structures. The synthetic conditions or form of the diphosphonate group are found to play a defining role in the adoption of this particular configuration of the inorganic component in the reported compounds and provide an additional strategy for the rational design of framework hybrid organic -inorganic solids. 2004-83 Dikarev, EV Shpanchenko, RV Andreini, KW Block, E Jin, J Petrukhina, MA Powder diffraction study of a coordination polymer comprised of rigid building blocks: [Rh-2(O2CCH3)(4)center dot mu(2)-Se2C5H8-Se,Se '](infinity) INORGANIC CHEMISTRY 43, 2004, 5558-5563. The crystal structure of a new hybrid product comprised of two rigid building blocks, namely dirhodium(II) tetraacetate, [Rh-2(O2CCH3)(4)] (1), and 2,6-diselenaspiro[3.3]heptane, Se2C5H8 (2), has been solved ab initio using laboratory source X-ray powder diffraction (XRPD) data. The rigid body refinement approach has been applied to assist in finding an adequate model and to reduce the number of the refined parameters. Complex [Rh-2(O2CCH3)(4).mu(2)Se(2)C(5)H(8)-Se,Se'] (3) conforms to the triclinic unit cell with lattice parameters of a = 8.1357(4), b = 8.7736(4), and c = 15.2183(8) Angstrom, alpha = 77.417(3), beta = 88.837(3), and gamma = 69.276(4)degrees, V = 989.66(8) Angstrom(3), and Z = 2. The centrosymmetric P (1) over bar space group was selected for calculations. The final values of the reduced wR(p), R-p, and chi(2) were calculated at 0.0579, 0.0433, and 5.95, respectively. The structure of 3 is a one-dimensional zigzag polymer built on axial Rh...Se interactions at 2.632(6) Angstrom. The 2,6-diselenaspiro[3.3]heptane ligand acts as a bidentate linker bridging dirhodium units via both selenium atoms. The geometrical parameters of individual groups for rigid body refinement have been obtained from X-ray powder data for dirhodium(II) tetraacetate (1) and from single-crystal X-ray diffraction for diselenium molecule 2. The crystal structures of 1 and 2 are reported here for the first time. For 1 indexing based on XRPD data has resulted in the triclinic unit cell P (1) over bar with lattice parameters of a = 8.3392(7), b = 5.2216(5), and c = 7.5264(6) Angstrom, alpha = 95.547(10), beta = 78.101(6), and gamma = 104.714(13)degrees, V = 309.51(5) Angstrom(3), and Z = 1. The final values were wR(p) = 0.0452, R-p = 0.0340, and chi(2) = 1.99. The 1D polymeric motif built on axial Rh...O interactions of the centrosymmetric dirhodium units has been confirmed for the solid-state structure of 1. Compound 2,6-diselenaspiro[3.3]heptane (2) conforms to the monoclinic space group P2(1)/c with the unit cell parameters of a = 5.9123(4), b = 19.6400(13), and c = 5.8877(4) Angstrom, beta = 108.5500(10)degrees, V = 648.15(8) Angstrom(3), and Z = 4. 2004-84 ???? Harvey, HG Slater, B Attfield, MP Rational design of the pore system within the framework aluminium alkylenediphosphonate series CHEMISTRY-A EUROPEAN JOURNAL 10, 2004, 3270-3278. We report here on the solvothermal synthesis and crystal structure of the hybrid organic-inorganic framework material Al-2[O3PC3H6PO3](H2O),F-2.H2O (orthorhombic, Pmmn, a = 12.0591(2) Angstrom, b = 19.1647(5) Angstrom, c = 4.91142(7) Angstrom, Z = 4), the second member of the Al-2[O3PCnH2nPO3](H2O)(2)F-2.H2O series. The structure consists of corrugated chains of corner-sharing AlO4F2 octahedra in which alternating AlO4F2 octahedra contain two fluorine atoms in a trans or a cis configuration. The diphosphonate groups link the chains together through Al-O-P-O-Al bridges and through the propylene groups to form a three-dimensional framework structure containing a one-dimensional channel system. The linkage of the corrugated inorganic Al-O-P layers within the structure results in the formation of two types of channel that differ in size, shape and composition. The smaller channel is unoccupied; the larger channel is more elongated and contains two extra-framework water molecules per unit cell. A computational investigation into the driving force that controls the stacking arrangement of the Al-O-P inorganic layers within this series of compounds reveals that the stacking is found to be controlled by thermodynamic factors, arising chiefly from the conformation of the organic linker molecule used to connect the inorganic sheets. It is found that the registration of the inorganic layers can be engineered by selecting an appropriate, simple organic spacer or linker alkyl chain, where an even number of carbon atoms in the alkyl chain directs formation of aligned, stacked, inorganic sheets (AAAAAA), and an odd number directs formation of unaligned, stacked sheets (ABABAB) and the formation of one or two channel types in the resultant structure, respectively. This combination of alkyl-chain linkers in conjunction with corrugated inorganic layers is an effective tool to rationally design the pore system of hybrid framework materials. 2004-85 Yang, Z Chen, XL Liang, JK He, M Chen, JR The crystal structure of alpha-SrGaBO4 CRYSTAL RESEARCH AND TECHNOLOGY 39, 2004, 634-642. A new compound alpha-SrGaBO4 has been synthesized by solid state reaction at high temperatures, and its structure has been solved by direct methods from powder X-ray diffraction. alpha-SrGaBO4 has an orthorhombic system, Pccn space group, with lattice parameters a = 15.3154(7) Angstrom, b = 8.9186(4) Angstrom, c = 5.8130(3) Angstrom, and Z = 8. The structure consists of infinite chains run parallel to the c axis and built up of GaO4 tetrahedral and BO3 triangles. The basic unit of these chains is a six - membered Ga2BO8 ring formed by two GaO4 tetrahedra and one BO3 triangles. The Sr atom is bonded to eight oxygen atoms. The strontium atoms serve to hold the chains together through co-ordination with oxygen atoms. DTA curve of noncrystalline glassy SrGaBO4 was discussed. The XRD results show no phase transition occurs between -173degreesC and 127degreesC. 2004-86 Azuma, M Yoshida, H Saito, T Yamada, T Takano, M Pressure-induced buckling of spin ladder in SrCU2O3 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 126, 2004, 8244-8246. Pressure-induced structural phase transition of spin ladder compound SrCu2O3 was investigated by synchrotron X-ray powder diffraction with a diamond anvil cell (DAC). The change was characterized by a buckling of the Cu2O3 plane in the rung direction of the ladder. The structure of the high-pressure phase was found to be essentially the same as that of CaCu2O3. Application of an external pressure of 3.4 GPa therefore affected the structure in the same manner that the chemical (internal) pressure does. 2004-87 Baranska, M Lasocha, W Kozlowski, H Proniewicz, LM New solid state Ni(II)-famotidine square-planar complex: powder diffraction and spectroscopic studies JOURNAL OF INORGANIC BIOCHEMISTRY 98, 2004, 995-1001. Recent potentiometric studies have claimed that Ni(II) forms three pH-dependent complexes with famotidine. We isolated two of them from the solution; namely the paramagnetic complex NiL with octahedral geometry and the diamagnetic complex NiH-L-2 with square-planar geometry, The latter compound constitutes the subject of this work. The crystal structure of nickel (II) famotidine complex NiC8N7O2S3H13 discussed here, determined with the powder diffraction method, has shown that it belongs to a Pben space group (60) with a, b, c = 24.328(4), 14.747(2), 7.786(1), V = 2793.6(5) Angstrom 3. R-F and R-wp are 16.1% and 15.5%, respectively. Additionally, the UV-VIS, FT-FIR and Raman spectroscopic methods were employed to discuss and support the structure of the NiH-L-2 complex suggested by X-ray data. The structure presented in this work is the second example of the complex of a famotidine ligand with a transition metal ion in the solid state. The other one, reported from a single crystal X-ray structure of famotidine complex with Cu(II), is quite different. 2004-88 Lin, JH Sheptyakov, D Wang, YX Allenspach, P Structures and phase transition of vaterite-type rare earth orthoborates: A neutron diffraction study CHEMISTRY OF MATERIALS 16, 2004, 2418-2424. The structure of vaterite-type rare earth orthoborate (LnBO(3)) has long been a subject of interest and controversy. In the :present work, the crystal structures of two polymorphs of the vaterite-type rare earth orthoborates, i.e., the low- and high-temperature modifications of (Y0.92Er0.08)BO3, were solved and refined from neutron powder diffraction data. The low-temperature polymorph crystallizes in a C-centered monoclinic cell with C2/c space symmetry, the unit cell parameters being alpha = 11.3138(3) Angstrom, b = 6.5403(2) Angstrom, c = 9.5499(2) Angstrom, and beta = 112.902(1)degrees. The boron atoms in the structure are all tetrahedrally coordinated and form the three-membered ring borate B3O9 groups. The high-temperature form crystallizes in a new structure type in a monoclinic cell with C2/c space symmetry, and the unit cell constants alpha = 12.2019(3) Angstrom, b = 7.0671(2) Angstrom, c = 9.3424(2) Angstrom, and beta = 115.347(1)degrees. The borate groups in the high-temperature structure are all isolated flat BO3 triangles. As far as the structural chemistry is concerned, both structures are different from the typical CaCO3 vaterite. However, they do share some common features, particularly the packing fashion of the cations, which results in similarly looking X-ray diffraction patterns as that of the typical vaterite. 2004-89 Veith, GM Lobanov, MV Emge, TJ Greenblatt, M Croft, M Stowasser, F Hadermann, J Van Tendeloo, G Synthesis and characterization of the new Ln(2)FeMoO(7) (Ln = Y, Dy, Ho) compounds JOURNAL OF MATERIALS CHEMISTRY 14, 2004, 1623-1630. The new compounds Ln(2)FeMoO(7) (Ln = Y, Dy, Ho) have been synthesized by solid-state reaction in evacuated silica tubes. The crystal structure of Dy2FeMoO7 and Ho2FeMoO7 was determined ab initio by simulated annealing in the R(3) over bar space group. Transmission electron microscopy study of Y2FeMoO7 revealed an unusual lamellar microstructure, composed of blocks with the structure of different zirconolite polymorphs. The dominant form corresponds to the zirconolite-2M type structure ( space group C2/c) with a partially ordered array of Fe and Mo ions. X-Ray near edge spectroscopy data are consistent with formally Fe3+ and Mo5+ oxidation states for all compounds. Magnetic and transport measurements are reported. 2004-90 Opozda, EM Lasocha, W Wlodarczyk-Gajda, B Synthesis and characterization of some unsymmetrical Schiff base ligands and their nickel(II) complexes incorporating o-phenylenediimine units ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 630, 2004, 597-603. Six new nickel(II) complexes of the unsymmetrical Schiff base ligands derived from o-phenylenediamne were synthesized. These complexes were prepared by template and non-template reactions of the precursor 3-acetyl-4-[N-(2'-aminophenyl)-amino]-3-buten-2-one (HLdegrees) with appropriate o-hydroxycarbonyl aromatic compounds, aromatic 1,3-oxo aldehydes and 1,3-diketones. The nickel(II) compounds were characterized by analytical and spectroscopic methods. Crystal structure of complex [3-acetyl-(6,7)-benzo-8-salicylidene-5,8-diazahepta-3-ene-2-onato(2-)]ni ckel(II) (NiL1) has been determined by X-ray powder diffraction method, revealed that the molecules are almost flat, and there are no forces other than van der Waals interactions between molecules. The structure was solved by global optimisation technique and refined by the Rietveld method, obtained R-F and R-wp are 11.6 and 17.4%, respectively. The synthesis of a new unsymmetrical nickel(II) tetraazamacrocyclic complex is also described. 2004-91 Bostrom, M Gemmi, M Schnelle, W Eriksson, L Synthesis, properties and structure determination of Nb2O3(SO4)(2)center dot(1)/4H2O from neutron and synchrotron X-ray powder diffraction data JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 1738-1745. The blue diamagnetic compound Nb2O3(SO4)(2) (.) 1/4H(2)O was synthesized by the reaction of niobium metal and boiling sulfuric acid. The unit cell was deduced from electron diffraction patterns and the crystal structure was solved from X-ray powder diffraction data and refined from combined X-ray synchrotron and neutron powder diffraction data. Nb2O3(SO4)(2) (.) 1/4H(2)O crystallizes in the space group R-3 (148) with the cell parameters a = 10.384(2) Angstrom and c = 26.55(2) Angstrom in the hexagonal setting. The structure features covalently bonded sulfate tetrahedra and niobate octahedra. 2004-92 ????? Anokhina, EV Jacobson, AJ [Ni2O(L-Asp)(H2O)(2)]center dot 4H(2)O: A homochiral 1D helical chain hybrid compound with extended Ni-O-Ni bonding JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 126, 2004, 3944-3045. 2004-93 Jurgens, B Irran, E Hoppe, HA Schnick, W Phase transition of a dicyanamide with rutile-like structure: Syntheses and crystal structures of alpha- and beta-Cd[N(CN)(2)](2) ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 630, 2004, 219-223. Cadmium dicyanamide Cd[N(CN)(2)](2) was synthesized through aqueous ion exchange at room temperature. A reversible phase transition was detected by in situ X-ray powder diffractometry above 55 degreesC. The crystal structures of both phases were determined by X-ray powder diffraction (beta-Cd[N(CN)(2)](2): T = 22 degreesC, a = 621.60(3), b = 748.76(4), c = 770.21(5) pm, beta = 91.784(3)degrees, P2(1)/n (no. 14), Z = 2, wR(p) = 0.063, R-p = 0.050, R-F = 0.059; alpha-Cd[N(CN)(2)](2): T = 150 degreesC, a = 624.62(5), b = 752.92(6), c = 768.30(7) pm, Pnnm (no. 58), Z = 2, wR(p) = 0.083, R-p = 0.064, R-F = 0.087). Both polymorphs consist of Cd2+ and bent planar [N(CN)(2)](-) ions. alpha-Cd[N(CN)(2)](2) crystallizes analogously to rutile and is isotypic with M-II[N(CN)(2)](2) (M = Mg, Cr, Mn, Co, Ni, Cu). The monoclinic low-temperature polymorph beta-Cd[N(CN)(2)](2) is closely related to that of the orthorhombic high-temperature polymorph alpha-Cd[N(CN)(2)](2) by a translationengleiche transition of index 2. 2004-94 Cremer, U Ruschewitz, U NaCu5(C-2)(3): The first alkali metal transition metal acetylide with a three-dimensional framework structure ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 630, 2004, 161-166. By heating the red residue of the reaction of NaC2H and CuI in liquid ammonia at 463 K for 30 min in a dynamic vacuum orange polycrystalline NaCu5(C-2)(3) is obtained. The crystal structure was solved and refined from X-ray powder diffraction data (orthorhombic, Puma, a 732.80(2) pm, b = 1099.63(4) pm, c = 726.15(2) pm, Z = 4 R-B = 0.030). It consists of a three-dimensional framework of Cu-I and C-2(2-) ions with small channels running parallel to [100] and [001]. The sodium ions reside at the inter-sections of these channels. The vibrational spectra of NaCu5(C-2)(3) show some similarities with the spectra of phenylethynylcopper(I), but they are different to those Of Cu2C2. Therefore NaCu5(C-2)(3) does probably not represent a crystalline model compound for the unknown structure of amorphous Cu2C2. 2004-95 Hostettler, M Schwarzenbach, D Helbing, J Dmitriev, V Weber, HP Structure and SHG of the high pressure phase IV of HgBr2 SOLID STATE COMMUNICATIONS 129, 2004, 359-363. Angle dispersive X-ray diffraction experiments on mercuric bromide (HgBr2) under high pressure up to 11.0 GPa were carried out at room temperature using synchrotron radiation. In addition to the already known four different phases of HgBr2 in the pressure-temperature range of p < 4.5 GPa, 90 < T < 600 K Our observations show the existence of a new phase (V) above 9.0 GPa and, together with published material, support the phase transition sequence: (I) orthorhombic-(II) orthorhombic-(III) monoclinic-(IV) trigonal-(V) trigonal/hexagonal. The structure of phase IV with space group symmetry P3 has been determined from powder diffraction data. The observation of second-harmonic-generation signals confirms the absence of an inversion center. The structure of phase IV is a commensurately modulated variant of the CdI2 type layer structure, where part of the Hg atoms are displaced from the centers of the HgBr6 octahedra by a much as 0.76 Angstrom in the direction perpendicular to the layers. 2004-96 Harvey, HG Attfield, MP Synthesis, crystal structures, and properties of novel lamellar gallium methylenediphosphonates CHEMISTRY OF MATERIALS 16, 2004, 199-209. Three new gallium methylenediphosphonates: (C5H5NH)[Ga-2(H2O)(2)(O3PCH2PO3)(O3PCH2-PO3H)] (1) (monoclinic, P2(1)/c, a = 11.0848(2) Angstrom, b = 8.4441(2) Angstrom, c = 9.4419(1) Angstrom, beta = 104.537(1)degrees, Z = 2), [(CH3)(4)N][Ga-2(H2O)(2)(O3PCH2PO)(O3PCH2PO3H)] (2) (monoclinic, C2/c, a = 22.1628(8) Angstrom, b = 8.5724(2) Angstrom, c = 9.4455(2) Angstrom, beta = 95.486(3)degrees, Z = 4), and (C5H5NH)[Ga(H2O)(O3PCH2PO3)] (3) (monoclinic, P2(1)/a, a = 9.5721(7) Angstrom, b = 8.6140(6) Angstrom, c = 12.894(1) Angstrom,beta = 99.961(3)degrees, Z = 4) have been synthesized by solvothermal methods in the presence of organocations, and their structures were determined using powder (1 and 2) and single-crystal X-ray diffraction data (3). All three materials contain a novel corrugated [Ga(H2O)(O3PCH2PO3)](-) layer motif composed of octahedral GaO5(OH2) units that are linked together by the diphosphonate groups. One of the oxygen atoms of each diphosphonate group protrudes into the interlamellar region where it hydrogen bonds to adjacent layers in 1 and 2 to form hydrogen-bonded framework structures, or to the pyridinium. cations in the lamellar material 3. The stacking arrangement of the layers in 1 and 2 is shown to be dependent on the organocations present during the synthesis, and to form materials with one- or two-types of hydrogen-bonded channels, respectively. Material 3 is an intermediate phase isolatable during formation of 1 and is convertible to the type of hydrogen-bonded framework of 1 by solvothermal, thermal, or solution ion-exchange methods. 2004-97 Nunes, C Suryanarayanan, R Botez, CE Stephens, PW Characterization and crystal structure of D-mannitol hemihydrate JOURNAL OF PHARMACEUTICAL SCIENCES 93, 2004, 2800-2809. The objectives of this study were (i) to isolate and characterize mannitol hydrate, and (ii) to solve its crystal structure from high-resolution synchrotron X-ray powder diffraction data. Mannitol hydrate was prepared by freeze-drying aqueous mannitol solutions (5% w/v) under controlled conditions. X-ray powder diffractometry, differential scanning calorimetry, and thermogravimetric analyses indicated that mannitol exists as a hemihydrate (C6H14O6 . 0.5H(2)O). Synchrotron data were collected on the X3B1 beamline at the National Synchrotron Light Source. The simulated annealing program PSSP was used to solve the structure, which was subsequently refined by Rietveld analysis using the program package GSAS. The compound crystallizes in space group P1, with alpha=9.8963 Angstrom, b=10.5424 Angstrom, c=4.7860 Angstrom, alpha=102.589degrees, beta = 86.092degrees, and gamma =116.079degrees. The unit cell contains two dissimilar D-mannitol molecules and one water molecule, forming a hydrogen bonding pattern significantly different from that seen in the anhydrous polymorphs. 2004-98 Dinnebier, R Sofina, N Jansen, M The structure of the high temperature modification of lithium triflate (gamma-LiSo(3)CF(3)) ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 630, 2004, 1613-1616. The high temperature modification of lithium triflate (gamma-LiSO3CF3) crystallises in the orthorhombic space group Cmca with the lattice parameters a = 6.3022(4), b = 8.6989(5), and c 20.1262(14) Angstrom (synchrotron powder diffraction data, T 456 K). The crystal structure of gamma-LiSO3CF3 is disordered, in the cationic as well as the anionic partial structure, and exhibits double layers of triflate anions with the lipophilic CF3-groups facing each other. The lithium ions could not be located by the diffraction experiment due to their high mobility. The staggered triflate anion is twofold disorderd leading to two different positions on top of each other which are tilted to one another. 2004-99 ??? Zanardi, S Alberti, A Cruciani, G Corma, A Fornes, V Brunelli, M Crystal structure determination of zeolite Nu-6(2) and its layered precursor Nu-6(1) ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 43, 2004, 4933-4937. 2004-100 Kirik, SD Mulagaleev, RF Blokhin, AI [Pd(CH3COO)(2)](n) from X-ray powder diff raction data ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS 60, 2004, M449-M450. The water-insoluble title compound, catena-poly[palladium(II)-di-mu-acetato-kappa(4)O:O'], [Pd(C2H3O2)(2)](n), was obtained from a nitratopalladium solution and acetic acid as a pale-pink powder. Ab initio crystal structure determination was carried out using X-ray powder diffraction techniques. Patterson and Fourier syntheses were used for atom location and the Rietveld technique was applied for the final structure refinement. The structure consists of palladium acetate complexes connected into polymeric chains running along b, in which two Pd atoms are bridged by two acetate groups that are in a cis configuration with respect to one another. The unique Pd atom lies on a site with 2/m symmetry and the acetate moieties have imposed m symmetry; these are joined into infinite chains running along the b direction. The shortest Pd...Pd distance in the row is 2.9192 (1) Angstrom. The planes of adjacent palladium complexes are inclined towards each other, the angle between the planes being approximately 30degrees. 2004-101 Muhle, C Nuss, J Dinnebier, RE Jansen, M On potassium tetracyanoplatinate(II), potassium tetracyanopalladate(II), and their monohydrates ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 630, 2004, 1462-1468. We have determined the crystal structures of the potassium tetracyanoplatinates(II) and -palladates(II), and of their monohydrates, by X-ray powder diffraction techniques and single crystal structure analysis. K-2[Pt(CN)(4)]: orthorhombic; Pccn; a = 1370.11(2); b = 907.09(1); c = 703.91(2) pm; Z = 4; R-F(2) = 0.0903 (N(hkl) = 415). K-2[Pt(CN)(4)] . H2O: orthorhombic; Pnna; a = 715.79(4); b = 977.91(6); c = 1322.46(8) pm; Z = 4; R(F)(N') = 0.027 (N'(hkl) = 1066). K-2[Pd(CN)(4)]: monoclinic; P2(1)/c; a = 433.03(2); b = 782.90(3); c = 1328.17(6) pm; beta = 93.069(3)degrees; Z = 2; R-p = 0.0583 (N(hkl) = 352). K-2[Pd(CN)(4)] . H2O: orthorhombic; Pnna; a = 721.48(6); b = 976.77(8); c = 1326.4(1) pm; Z = 4; R(F)(N') = 0.048 (N'(hkl) = 1137). In all examined representatives the anions are stacked one upon the other, even though they are tilted in part. The results are completed by spectroscopic and thermo analytical investigations. 2004-102 Ei-Himri, A Marrero-Lopez, D Nunez, P TI Pt2Mo3N and PdPtMo3N: new interstitial nitrides prepared from freeze-dried precursors SO JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 3219-3223. AB The molybdenum bimetallic and trimetallic nitrides Pt2Mo3N and PdPtMo3N have been synthesized by ammonolysis of the stoichiometric amorphous precursor, obtained by freeze drying of aqueous solutions of the appropriate metal salts. These compounds have been characterized by elemental analysis, energy-dispersive analysis of X-rays, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and thermogravimetry analysis under an oxygen atmosphere. Pt2Mo3N and PdPtMo3N crystallize in the cubic space group P4(1)32 (213), with lattice parameters of a = 6.83586(4) and 6.82542(3) Angstrom, respectively, and form with the unusual filled beta-manganese structure. These compounds are stable under air up to 580 K, the oxidation being complete at 910K. 2004-103 Lobanov, MV Greenblatt, M Caspi, EN Jorgensen, JD Sheptyakov, DV Toby, BH Botez, CE Stephens, PW Crystal and magnetic structure of the Ca3Mn2O7 Ruddlesden-Popper phase: neutron and synchrotron x-ray diffraction study JOURNAL OF PHYSICS-CONDENSED MATTER 16, 2004, 5339-5348. The crystallographic and magnetic structures of Ca3Mn2O7 Ruddlesden-Popper phase have been determined by a combination of neutron and synchrotron x-ray diffraction. Two-phase behaviour observed at room temperature is attributed to an incomplete structural phase transition. The magnetic structure was solved in the Cm'c2'(1) Shubnikov group with dominant G-type antiferromagnetic order in the perovskite bilayers. The temperature evolution of the structural and magnetic parameters is presented. 2004-104 Amami, M van Smaalen, S Salah, AB Helluy, X Sebald, A Structural investigation of trimethylammonium tetrachloromercurate JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 2961-2970. The temperature dependence of the crystal structure of TrMA(2)HgCl(4) (TrMA = trimethylammonium) is studied by single-crystal and powder X-ray diffraction between 161 and 373 K. Below room temperature, we did not find significant changes of the crystal structure. The phase transition at 325 K is described by a rotation of one of the two independent TrMA(+) cations by 40degrees around the N-H axis, resulting in major rearrangements in the network of hydrogen bonds. A large change of the volume of the unit cell is found at the phase transition at 357 K, resulting in damage to the single crystals. Powder diffraction then shows that this transition can be described as a alpha-beta transition between the alpha and beta-K2SeO4 structure types. Structure refinements employing alternatively restrictions by the space group and additional restrictions by the C-3 non-crystallographic site symmetry for the TrMA(+) cations show that significant deviations from C-3 symmetry of the TrMA(+) cations do not exist at any temperature. The molecular dynamics and orientational disorder were studied by the maximum entropy method applied to the X-ray data. The diffraction results are corroborated by temperature dependent NMR experiments. 2004-105 ??? Nyman, M Bonhomme, F Alam, TM Parise, JB Vaughan, GMB [SiNb12O40](16-) and [GeNb12O40](16-): Highly charged Keggin ions with sticky surfaces ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 43, 2004, 2787-2792. 2004-106 Derollez, P Hernandez, O Hedoux, A Guinet, Y Masson, O Lefebvre, J Descamps, A Structural and microstructural description of the glacial state in triphenyl phosphite from powder synchrotron X-ray diffraction data and Raman scattering investigations JOURNAL OF MOLECULAR STRUCTURE 694, 2004, 131-138. The structure and microstructure (refinement of the isotropic size and microstrain parameters) of the glacial state in triphenyl phosphite (TPP, P(OC6H5)(3)) transformed at 222K have been determined from powder synchrotron X-ray diffraction data through a Rietveld and a Le Bail refinement, respectively. It is shown that the glacial state is composed of crystallites of the stable crystal phase coexisting with non-transformed supercooled liquid, the apparent size of the crystallites-depending on the aging temperature at which the glacial state is isothermally formed, [Phys. Rev. B 60 (1999) 9390]-being equal to 329.2(2) Angstrom at 222K. The molecular conformation is slightly less mirror-symmetric than the one in the crystal state, and correlatively only one of the two unusual weak intermolecular C-H...O hydrogen bonds already observed in the latter state is encountered in the glacial one. Additional Raman scattering investigations confirm the previous result and reveal in addition that no hydrogen bonding interaction is observed neither in the glass nor in the liquid states. 2004-107 Solovyov, LA Kim, TW Kleitz, F Terasaki, O Ryoo, R Comprehensive structure analysis of ordered carbon nanopipe materials CMK-5 by X-ray diffraction and electron microscopy CHEMISTRY OF MATERIALS 16, 2004, 2274-2281. The structure of ordered mesoporous carbon materials CMK-5 was analyzed in detail by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis by applying the recently developed continuous density function technique. The materials present twodimensional (2-D) hexagonally ordered arrays of carbon nanopipes formed within the mesopores of SBA-15 silica templates used for their fabrication. The series of CMK-5 carbons were synthesized by applying the templates of different pore widths and two carbon precursors: furfuryl alcohol and acenaphthene. All the materials were well-ordered, exhibiting five distinct XRD reflections, high nitrogen BET specific surface areas (about 2500 m(2)/g), and large pore volumes (about 2 cm(3)/g). TEM analysis and XRD modeling allowed precise determination of the mesostructure characteristics such as the nanopipe diameter, wall thickness, and shape. Around 15% of the space between the nanopipes was found to be occupied by carbon interconnections formed inside the complementary pores of the SBA-15 templates. The structure parameters determined correlated well with the synthesis procedures and were fully consistent with the nitrogen adsorption and thermogravimetric data. The differences in the properties and the formation mechanisms of the materials synthesized by applying furfuryl alcohol and acenaphthene carbon precursors were analyzed based on the whole scope of data obtained. 2004-108 Meshi, L Talianker, M Munitz, A Determination of the structure of UFe2Al10 compound JOURNAL OF ALLOYS AND COMPOUNDS 370, 2004, 206-210. The atomic structure of a new ternary phase UFe2Al10 appearing in the U-Fe-Al system was determined using direct methods applied to X-ray powder diffraction data. High resolution electron microscopy combined with the methods of crystallographic image processing was used for the verification of the structural model. The UFe2Al10 phase is orthorhombic and belongs to Cmcm space group, its unit cell contains 40 Al, eight Fe, and four U atoms. The lattice parameters obtained after Rietveld refinement are: a = 8.919 Angstrom, b = 10.208 Angstrom, and c = 9.018 Angstrom. The reliability factors characterizing the Rietveld refinement procedure are: R-p = 5.9%, R-wp = 8.1%, and R-b = 2.9%. 2004-109 Chen, XL He, M Xu, YP Li, HQ Tu, QY KCaF(CO3) from X-ray powder data 60, 2004, 150-151. ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE Potassium calcium fluoride carbonate, KCaF(CO3), has been synthesized and its structure solved from X-ray powder diffraction data. The K, Ca, F and C atoms lie at sites with (6) over bar m2 imposed symmetry and the unique O atom has imposed mm site symmetry. The compound consists of Ca-F-Ca chains parallel to the c axis and planar CO3 groups perpendicular to the c axis, the corners of the hexagonal cell being occupied by K+ ions. The compound is not a solid solution, since the structure differs from those of both KF and CaCO3. 2004-110 Cheung, EY Harris, KDM Johnston, RL Kitchin, SJ Hadden, KL Zakrzewski, M Rationalizing the structural properties of bupivacaine base - A local anesthetic - Directly from powder X-ray diffraction data JOURNAL OF PHARMACEUTICAL SCIENCES 93, 2004, 667-674. Bupivacaine belongs to a family of 1-alkyl-2',6'-pipecoloxylidides, which has shown promise as reversible action potential blockers that can introduce prolonged local anesthetic effects. The crystal structure of the free-base form of bupivacaine has been determined directly from powder X-ray diffraction data using the Genetic Algorithm technique for structure solution, followed by Rietveld refinement. This work further emphasizes the scope and utility of ab initio structure solution directly from powder X-ray diffraction data for tackling structural problems within the biomedical field, leading to opportunities for the investigation of structure-property relationships. 2004-111 Gonzalez-Mendez, LM Cumbrera, FL Garcia-Cuesta, MC Sanchez-Bajo, F Ortiz, AL Higes-Rolando, FJ Luna-Giles, F Ab initio structural determination of 2-(2-pyridyl)imino-N-(2-thiazolin-2-yl)thiazolidine from powder diffraction data MATERIALS LETTERS 58, 2004, 672-678. Structural determination using X-ray powder diffraction is usually restricted to relatively simple structures, although powder diffraction data are frequently used to refine, via the Rietveld method, approximately known structures. In this work, the relatively complex crystalline structure of a compound of high pharmaceutical interest (C11H12N4S2) has been firstly ab initio determined from its X-ray powder diffraction pattern and subsequently refined by the Rietveld method. This refined structure is in excellent agreement with that obtained previously from single-crystal data. As a consequence of the severe overlapping between adjacent reflections, direct methods failed, whereas we obtained good outcomes with 'real space' methods. This work shows that within the current state-of-art (hardware, software, numerical methods, etc.), relatively complex structures can be afforded by means of powder diffraction. 2004-112 Hu, XR Yuan, ZQ Lu, GL Determination of crystal structures of polymorphic chlorothalonil using Monte Carlo simulated annealing and Rietveld refinement POWDER DIFFRACTION 19, 2004, 325-328. Crystal structures of types II and III chlorothalonil, 2,4,5,6-tetrachloro-1,3-dicyanobenzene, (C8Cl4N2) were solved by applying Monte Carlo simulated annealing techniques to X-ray powder diffraction data and refined using the Rietveld method. Both types of chlorothalonil crystallize in monoclinic symmetry (space group P2(1) and two molecules per unit cell). Lattice parameters are: a=8.1615(18) Angstrom, b=9.4191(19) Angstrom, c=6.4728(14) Angstrom, beta=93.7307(64)degrees and V=497.8 Angstrom(3) for type II, and a=8.6003(10) Angstrom, b=9.2382(11) Angstrom, c=6.3024(7) Angstrom, beta=96.2152(60)degrees and V=498.5 Angstrom(3) for type III. The structures of both types of chlorothalonil are stacked by two coplanar molecular sheets paralleled to the b-axis. The adjacent two paralleled molecules in type II are on the same plane, while those in type III are on two different parallel planes. 2004-113 Dikarev, EV Chernyshev, VV Shpanchenko, RV Filatov, AS Petrukhina, MA Bulk material vs. single crystal: powder diffraction to the rescue DALTON TRANSACTIONS iss 24, 2004, 4120-4123. The crystal structure of bulk microcrystalline material obtained by interaction of two rigid building blocks, namely dirhodium(II) tetra(trifluoroacetate), [Rh-2(O2CCF3)(4)], and bis(4'-pyridyl) diphenylsilane, (C6H5)(2)Si(C5H4N)(2), has been solved ab initio using X-ray powder diffraction data. The title product of the 1:1 composition, [Rh-2(O2CCF3)(4).(mu(2)-(C6H5)(2)Si(C5H4N)(2))], is a one-dimensional zigzag polymer built on axial Rh...N interactions averaged at 2.16 Angstrom. Its structural characterization complements the previously reported product of the 2:1 composition obtained from the same reaction, namely {[Rh-2(O2CCF3)(4)](2).(mu(4)-(C6H5)(2)Si(C5H4N)(2))}. The latter has a 2D layered network revealed by the single crystal diffraction study. A combination of powder and single crystal X-ray techniques is shown to be methodologically important and complementary for understanding of product assembling in the system. 2004-114 Evans, IR Howard, JAK Szecsenyi, KM Leovac, VM Jacimovic, ZK Synthesis, characterization and crystal structure of a novel Ni(II) complex, Ni(L-H)(2) (L=3,5-dimethyl-1-thiocarboxamidopyrazole) JOURNAL OF COORDINATION CHEMISTRY 57, 2004, 469-476. A new complex, Ni(L-H)(2), L = 3,5-dimethyl-1-thiocarboxamidopyrazole, has been synthesized and characterized by IR spectroscopy, magnetic and electrical measurements. Its crystal structure was solved from powder X-ray diffraction data. The compound crystallizes in space group P (1) over bar with two independent half-molecules containing Ni(II) coordinated by four nitrogen atoms in a square-plane. The packing pattern consists of two stacks of parallel molecules mutually tilted at an angle of 118degrees. 2004-115 ??? Rubin-Preminger, JM Bernstein, J Harris, RK Evans, IR Ghi, PY Variable temperature studies of a polymorphic system comprising two pairs of enantiotropically related forms: [S,S]-ethambutol dihydrochloride CRYSTAL GROWTH & DESIGN 4, 2004, 431-439. Of the four known polymorphs of [S,S] -ethambutol dihydrochloride, two transform in an enantiotropic single-crystal-to-single-crystaI phase transformation from Form II to Form I on heating. The crystal structures of these two forms have been solved and compared. Because the other two forms are metastable and are only obtained from the melt, single-crystal data could not be obtained on them. However, all four forms have been characterized, and their relative thermodynamic relationships have been investigated by variable-temperature solid-state C-13 NMR, variable-temperature powder X-ray diffraction studies, differential scanning calorimetry, and optical microscopy. 2004-116 Money, VA Evans, IR Elhaik, J Halcrow, MA Howard, JAK An X-ray powder diffraction study of the spin-crossover transition and structure of bis (2,6-dipyrazol-1-ylpyrazine)iron(II) perchlorate ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 60, 2004, 41-45. The crystal structure of the iron(II) spin-crossover compound [Fe(C10H8N6)(2)](ClO4)(2) in the high-spin state has been solved from powder X-ray diffraction data using the DASH program and refined using Rietveld refinement. The thermal spin transition has been monitored by following the change in unit-cell parameters with temperature. The title compound has been found to undergo a crystallographic phase change, involving a doubling of the crystallographic a axis, on undergoing the spin transition. 2004-117 Mahe, N Bataille, T Synthesis, crystal structure from single-crystal and powder x-ray diffraction data, and thermal behavior of mixed potassium lanthanide squarates: Thermal transformations of layered [Ln(H2O)(6)]K(H2C4O4)(C4O4)(2) into pillared LnK(C4O4)2 (Ln = Y, La, Gd, Er) INORGANIC CHEMISTRY 43, 2004, 8379-8386. A new series of mixed potassium and rare-earth squarates, [Ln(H2O)(6)]K(H2C4O4)(C4O4)(2) (Ln = Y, La, Gd, Er), has been synthesized and structurally characterized from single-crystal X-ray diffraction and spectroscopic analyses. The yttrium-based compound crystallizes with a monoclinic symmetry, space group C2/c [a = 8.3341(2) Angstrom, b = 37.7094(g) Angstrom, c = 11.7195(3) Angstrom, beta = 90.3959(9)degrees, V = 3683.1(2) Angstrom(3), Z = 8]. The structure is built from layers maintained together via hydrogen bonds. Within a layer, squarate ligands act as linkers between lanthanide and potassium cations. The thermal decomposition of the precursors has been studied by powder thermodiffractometry and thermal analyses. It is shown that crystalline intermediate phases are formed during the degradation. Among them, unprecedented mixed anhydrous squarates, LnK(C4O4)(2), could be isolated. The crystal structure of the Y compound has been solved ab initio from X-ray powder diffraction data, using direct-space methods [a = 6.2010(5) Angstrom, c = 11.639(l) Angstrom, V = 447.55 Angstrom(3), Z = 2]. The structure consists of layers of edge-sharing YO8 and KO8 antiprisms, pillared by mu(8)-squarate groups. The end of the precursor decomposition is marked by the formation of cubic sesquioxides Ln(2)O(3), including lanthanum oxide. 2004-118 Degtyareva, O McMahon, MI Nelmes, RJ Pressure-induced incommensurate-to-incommensurate phase transition in antimony PHYSICAL REVIEW B 70, 2004, 184119. An incommensurate composite phase with a monoclinic host-guest structure, designated Sb-IV, is found between the previously known Sb-I and Sb-II phases, and an incommensurate to incommensurate transition between phases II and IV is described. The monoclinic Sb-IV phase is observed on both pressure increase between 8.2 and 9.0 GPa and on pressure decrease between 8.0 and 6.9 GPa. The full structure of Sb-IV, including a determination of the structural modulations of the host and guest components, is reported from x-ray powder diffraction data. The high-pressure phase of arsenic, As-III, is shown to have the same monoclinic composite structure. 2004-119 Dacheux, N Clavier, N Robisson, AC Terra, O Audubert, F Lartigue, JE Guy, C Immobilisation of actinides in phosphate matrices COMPTES RENDUS CHIMIE 7, 2004, 1141-1152. In the field of the immobilisation of high-activity-level and long-life radwaste (HAVL) for a deep underground repository, several phosphate matrices were already proposed as good candidates to delay the release of actinides in the near-field of such disposal. Among them, thorium phosphate-diphosphate (TPD), monazites/brabantites, britholites, and TPD/monazite composites were extensively studied. The synthesis of samples doped with actinides (Th, U...) through wet and dry chemistry methods then their complete characterisation are reported. Their chemical durability is also examined. These materials appear as promising matrices to immobilise tetravalent and/or trivalent actinides. 2004-120 Brandel, V Dacheux, N Chemistry of tetravalent actinide phosphates - Part I JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 4743-4754. actinide (IV) phosphate; phosphates of tetravalent cations; thorium phosphate; uranium phosphate; neptunium phosphate; plutonium phosphate; protactinium phosphate The chemistry and crystal structure of phosphates of tetravalent cations, including that of actinides was reviewed several times up to 1985. Later, new compounds were synthesized and characterized. In more recent studies, it was found that some of previously reported phases, especially those of thorium, uranium and neptunium, were wrongly identified. In the light of these new facts an update review and classification of the tetravalent actinide phosphates is proposed in the two parts of this paper. Their crystal structure and some chemical properties are also compared to non-actinide cation phosphates. 2004-121 Martinez-Garcia, R Reguera, E Rodriguez, J Balmaseda, J Roque, J Crystal structures of some manganese(II) and cadmium hexacyanoferrates (II,III) and structural transformations related to the sorption of Cesium POWDER DIFFRACTION 19, 2004, 255-264. Mn2+ and Cd2+ form a family of isostructural hexacyanoferrates(II,III). Their crystal structures, including those of mixed compositions containing K+ and Cs+ as charge balance cations, were resolved and refined from XRD powder patterns. The crystal structures of M-3[Fe(CN)(6)](2)center dot xH(2)O and MCs2[Fe(CN)(6)] (where M=Mn, Cd) were refined in the space group Fm3m. The mixed salts, MK2[Fe(CN)(6)]center dot(2)H(2)O, were found to be orthorhombic (space group Pmn2(1)). The orthorhombic structure results from a local distortion due to monohydrated potassium ions located in interstitial sites. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+ is a large ion, which practically fills the available interstitial voids stabilizing the cubic structure. In solutions of K+ and Cs+ the single salts, M-2[Fe(CN)(6)]center dot 8H(2)O (monoclinic P2(1)/n) also transform, in this case liberating M2+ ions and forming the corresponding mixed salts. An analogous but slow structural transformation was also observed in the anhydrous forms of these single salts. These structural transformations could be relevant to the use of these compounds as ion exchangers and particularly for the sorption of Cs-137(+) from radioactive waste solutions. The XRD data were complemented with structural information from infrared (IR), Mossbauer and water vapor adsorption techniques. 2004-122 Martinez-Garcia, R Reguera, E Balmaseda, J Ramos, G Yee-Madeira, H On the crystal structures of some nickel hexacyanoferrates (II,III) POWDER DIFFRACTION 19, 2004, 284-291. The crystal structures of some nickel hexacyanoferrates (II, III), including mixed compositions containing Na+, K+ and Cs+, were resolved and refined from XRD powder patterns. Data from infrared, Mossbauer and adsorption techniques provided complementary structural information. The crystal structures of Ni-3[Fe(CN)(6)](2)center dot 16H(2)O and NiCS2[Fe(CN)(6)] were refined in space group Fm3m. NiNa2[Fe(CN)(6)]center dot 2H(2)O and NiK2[Fe(CN)(6)]center dot 2H(2)O were found to be orthorhombic (space group Pmn2(1)). This structure (Pmn21) results from a distortion around the alkali ion, which appears as a monohydrated interstitial species. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+ is a large cation and space is not available for interstitial water molecules. This orthorhombic model is also supported by the Mossbauer spectra of the ferrous analogs, FeK2[Fe(CN)(6)]center dot xH(2)O and Fe[Pt(CN)(6)]. 2004-123 Heymann, G Beyer, K Huppertz, H High-temperature synthesis, crystal structure, and properties of the new sodium rare-earth oxide borates Na2RE2(BO3)(2)O (RE = Dy, Ho) ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 59, 2004, 1200-1208. The new monoclinic oxide borates Na2RE2(BO3)(2)O (RE = Dy, Ho) were synthesized using standard solid-state reactions in the temperature range 900-950 degreesC. They are isotypic to the known phases Na2RE2(BO3)(2)O (RE = Y, La, Nd, Sm-Gd, Er). The single crystal X-ray structure determination of Na2Dy2(BO3)(2)O revealed: P2(1)/c, a 1063.9(l), b = 626.2(l), c = 1025.3(1) pm, beta = 117.76(1)degrees, Z = 4, Rl = 0.0221, wR2 = 0.0402 (all data). The corresponding lattice parameters of Na2HO2(BO3)(2)O determined from powder data are a = 1061.2(5), b = 623.7(2), c = 1022.5(3) pm, and 0 = 117.7(1)degrees. The structure consists of infinite sheets of REO8-polyhedra in the bc-plane, which are seperated by sodium atoms. The BO3-groups are isolated forming layers in the bc-plane. The results of IR- spectroscopic investigations, temperature-resolved in-situ powder-diffraction measurements, and DTA/TG measurements on Na2Dy2(BO3)20 are also presented. 2004-124 Ardizzoia, GA Brenna, S Castelli, F Galli, S LaMonica, G Masciocchi, N Maspero, A Metal imidazolato polymers: synthesis, characterization and crystal structure of new silver(I) triphenylphosphine derivatives POLYHEDRON 23, 2004, 3063-3068. When the polymeric complex [Ag(im)](n) (Him = imidazole) is reacted with PPh3 (PPh3 = triphenylphosphine), it yields the [Ag-2(mu(2)-im)(2)(PPh3)(3)] and [Ag(mu(2)-im)(PPh3)(2)](n) species, shown to contain wavy chains of metal ions, singly bridged by N,N'-exobidentate imidazolate ligands. The former, crystallised as the CH2Cl2 solvate, contains two non-equivalent silver(I) ions, differing in the number of coordinated phosphines (one, in trigonal planar stereochemistry, or two, having tetrahedral geometry). The latter has a unique independent silver(I) ion in a tetrahedral environment, with two coordinated PPh3 ligands. The reactivity of known silver(I) azolates with PPh3, as well as the solution behaviour and (when available) the crystal structures of the corresponding derivatives are taken into consideration for a due comparison. 2004-125 Gredin, P Labeguerie, J Pierrard, A Vaulay, MJ de Kozak, A Synthesis and structural characterization of K0.33Gd0.67F2.33 (KGd2F7) and K0.31Gd0.69F1.84O0.27 SOLID STATE SCIENCES 6, 2004, 1221-1228. K0.33Gd0.67F2.33(KGd2F7) is synthesized by solid state reaction between KF and GdF3 at different temperatures (600, 700, 800 and 900 degreesC). For all temperatures, the crystal structure of K0.33Gd0.67F2.33 derives from that of the fluorite type. Nevertheless when the synthesis temperature increases, the X-ray powder pattern exhibits new superstructure diffraction lines. This feature is attributed to an anionic and cationic ordering. A structural model is elaborated and the crystal structure at 700 degreesC is determined by the Rietveld method. The oxyfluoride K0.31Gd0.69F1.83O0.27 is synthesized using a sol-gel route. Its crystal structure is close to that of K0.33Gd0.67F2.33 and differs only by a new anionic and cationic ordering. K0.33Gd0.67F2.33 and K0.31Gd0.69F1.83O0.27 are then just particular compositions of the solid solution formulated K1-xGdxF1+2x-2yOy. 2004-126 Broach, RW Sinkler, W Patton, RL Mezza, TM Gatter, MG Technique integration applied to structure solution: The case of UZM-5. Details of the structure, faulting and templating RECENT ADVANCES IN THE SCIENCE AND TECHNOLOGY OF ZEOLITES AND RELATED MATERIALS, PTS A - C 154, 2004, 1188-1196. The structure solution of the new zeolite framework UZM-5 is reviewed. It is shown how the structure solution emerges from integration of a number of zeolite characterization techniques such as powder X-ray diffraction, transmission electron microscopy, infrared spectroscopy and McBain adsorption. In addition to the ideal structure, faulting is evident in both powder X-ray diffraction and transmission electron microscopy. Details of the surface structure and faulting on the (001) planes are described. 2004-127 Hoyos, D Paillaud, JL Guth, JL Synthesis and structure determination of a novel lithium copper vanadate LiCu2VO4(OH)(2) SOLID STATE SCIENCES 6, 2004, 1359-1364. A novel lithium copper vanadate LiCu2VO4(OH)(2) (I) and Volborthite Cu3V2O7(OH)(2) are two phases obtained at 170degreesC by hydrothermal synthesis during the study of the CuO; V2O5; U2O; H2O system. Compound (1) crystallizes in the orthorhombic system, with the space group P2(1)2(1)2(1) (No. 19) and with the unit-cell parameters a = 9.6086(2) Angstrom, b = 8.4482(2) Angstrom, c = 5.8938(1) Angstrom. The structure was determined from powder by an "ab initio" method using the EXPO software and refined with GSAS, a Rietveld refinement package. Wave-like layers of rutile-type copper chains sharing vertex with the neighbor chains, are linked into a three-dimensional framework by rows of alternating tetrahedra of vanadium and trigonal bipyramids of lithium which share edges and vertices with the copper octahedra. 2004-128 Chernyshev, VV Stephens, PW Yatsenko, AV Ryabova, OB Makarov, VA Structural characterization of prazosin hydrochloride and prazosin free base JOURNAL OF PHARMACEUTICAL SCIENCES 93, 2004, 3090-3095. three-dimensional solid-state structures of prazosin hydrochloride, C19H22N5O4+ . Cl- (A), and prazosin free base, C19H21N5O4 (B), have been determined by synchrotron X-ray powder diffraction. A and B crystallize in triclinic P-1 and monoclinic Cc space groups, respectively, with one structural unit per asymmetric part. In A and B, the prazosin molecule adopts different conformations, which do not correspond to those obtained by DFT optimizations of protonated and free prazosin. 2004-129 Nomiya, K Yoshizawa, A Tsukagoshi, K Kasuga, NC Hirakawa, S Watanabe, J Synthesis and structural characterization of silver(I), aluminium(III) and cobalt(II) complexes with 4-isopropyltropolone (hinokitiol) showing noteworthy biological activities. Action of silver(I)-oxygen bonding complexes on the antimicrobial activities JOURNAL OF INORGANIC BIOCHEMISTRY 98, 2004, 46-60. Through two unequivalent oxygen donor atoms of the hinokitiol (Hhino; C10H12O2; 4-isopropyltropolone) ligand that showed noteworthy biological activities, the dimeric, silver(l)-oxygen bonding complex [Ag(hino)](2) 1, the monomeric aluminium(III) complex [AI(hino)(3)] . 0.5H(2)O 4 and the cobalt(II) complex "[Co(hino)(2)](2) . H2O" 6 were synthesized and characterized with elemental analysis, thermogravimetric and differential thermal analysis (TG/DTA), FTIR and solution (H-1 and C-13) NMR spectroscopy. The crystal structure of 1 was determined by Rietveld analysis based on X-ray powder diffraction (XPD) data and those of [Al(hino)(3)] . MeOH 4a and [Co(hino)(2)(EtOH)](2) 6a, being obtained as yellow block crystals and red platelet crystals, respectively, by crystallization of 4 and 6, were determined by single-crystal X-ray analysis. The antimicrobial activities of 1, 4 and 6, evaluated with minimum inhibitory concentration (MIC; mug ml(-1)), were compared with those of other metal complexes (M = Na, Li, Cs, Ca, V, Zn) with the hino(-) ligand. The antimicrobial activities observed in the alkali-metal salts strongly suggested that they were attributed to the effect of the anionic hino- species. The antimicrobial activities of 1 were significantly enhanced, whereas those of other metal complexes were suppressed, compared with those of the neutral Hhino and anionic hino- molecules. The antimicrobial activities observed in I were comparable with those of other recently found silver(l)-oxygen bonding complexes, the ligands of which had no activity. Thus, it is proposed that the antimicrobial activities of the silver(l)-oxygen bonding complexes are due to a direct interaction or complexation of the silver(l) ion with biological ligands such as protein, enzyme and membrane, and the coordinating ligands of the silver(l) complexes play the role of a carrier of the silver(l) ion to the biological system. 2004-130 ??? Clavier, N Dacheux, N Martinez, P de Kerdaniel, EDF Aranda, L Podor, R Sintering of beta-thorium-uranium(IV) phosphate-diphosphate solid solutions from low-temperature precursors CHEMISTRY OF MATERIALS 16, 2004, 3357-3366. Pure and single phase thorium-uranium(IV) phosphate-diphosphate beta-TUPD (orthorhombic form) dense pellets were prepared by two wet chemical routes from low-temperature precursors. The first method was based on the "direct evaporation" of a mixture containing tetravalent actinides and phosphoric acid while the second one involved the initial precipitation of the thorium-uranium(IV) phosphate-hydrogenphosphate hydrate (TUPHPH). Both methods led to single phase sintered samples following a two-step procedure using a uniaxial pressing at room temperature and then a heat treatment at high temperature. The dilatometric study and the determination of the linear shrinkage of the pellets showed that the best densification of the samples prepared via the "precipitation" method was obtained after heating the raw pellet at 1250 degreesC for 5 h, for initial uranium amount lower than 44.5 wt %(U). For samples prepared via "direct evaporation", the heat treatment must be prolonged for at least 15 h at this temperature. Moreover, the complete characterization of the samples (EPMA, and so forth) confirmed that the homogeneity of the samples was significantly improved when using TUPHPH as a precursor, probably due to the better reactivity of the initial powder (higher specific surface area, smaller grain size, and so forth). Several leaching tests were performed in various acidic media and in natural waters on beta-TUPD sintered samples. All the corresponding normalized dissolution rates remained low (10(-6) to 10(-5) g/(m(2) day)) even in aggressive media which confirms the high chemical durability of beta-TUPD, thus enhancing the potential use of this ceramic in the field of the efficient immobilization of tetravalent actinides. 2004-131 Bull, CL McMillan, PF Soignard, E Leinenweber, K Determination of the crystal structure of delta-MoN by neutron diffraction JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 1488-1492. We have determined the crystal structure of ordered hexagonal delta-MoN by use of powder X-ray diffraction and time-of-flight neutron diffraction. A disordered variety of the compound was first prepared by high-temperature ammonolysis Of MoCl5. This material has hexagonal symmetry with the space group P6(3)mc with a = 2.87(2) and c = 2.81 (1) Angstrom. Upon high pressure annealing, the N-atoms become ordered and the unit cell doubles in size: a = 5.73659(10) and c = 5.61884(17) Angstrom. The superconducting transition temperature increases from 4K in the disordered compound to 12.1 K in the ordered phase. 2004-132 Ling, CD Johnson, M Modelling, refinement and analysis of the "Type III" delta-Bi2O3-related superstructure in the Bi2O3-Nb2O5 system JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 1838-1846. The structure of the "Type III" delta-Bi2O3-related superstructure phase in the system Bi2O3-Nb2O5 is presented. A starting model was constructed by considering the crystal-chemistry of the system in the context of symmetry constraints determined by electron diffraction. After applying initial distortions, this could be Rietveld-refined against a combination of synchrotron X-ray and time-of-flight neutron powder diffraction data. The undistorted starting model was independently optimized using solid-state ab initio energy calculations, giving a fully optimized structure in excellent agreement with that obtained by Rietveld refinement. This dual approach both validates the structure and demonstrates the value of combining accurate total energy calculations with traditional refinement techniques for the solution of complex structures using powder diffraction data. The structure (Bi94Nb32O221, Z = l, I (4) over bar m2 (#119), a = 11.52156(18), c = 38.5603(6) A) consists of interacting corner-connected strings of NbO6 octahedra along <110>(F) directions of the FCC subcell, and can be described as a hybrid of fluorite and pyrochlore types. 2004-133 Hong, SB Lear, EG Wright, PA Zhou, WZ Cox, PA Shin, CH Park, JH Nam, IS Synthesis, structure solution, characterization, and catalytic properties of TNU-10: A high-silica zeolite with the STI topology JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 126, 2004, 5817-5826. A high-silica zeolite (Si/Al = 7.1) with the STI framework topology, denoted TNU-10, has been synthesized in the presence of 1,4-bis(N-methylpyrrolidinium)butane and Na+ cations as structure-directing agents, and its structure in the proton form has been refined against laboratory powder X-ray data in space group Fmmm (a = 13.533(1) Angstrom, b = 17.925(2) Angstrom, c = 17.651(2) Angstrom). The space group symmetry is supported by electron diffraction and energy minimization studies. The as-made and proton form of TNU-10 are extensively characterized by elemental and thermal analyses, scanning electron microscopy, N-2 adsorption, multinuclear solid-state NMR, IR, and temperature-programmed desorption of ammonia, and the location of the organic structure-directing agent in the channel system is determined by molecular modeling. The catalytic properties of H-TNU-10 and Co-TNU-10 are evaluated for the skeletal isomerization of 1-butene to isobutene and the selective reduction of NO with methane, respectively. When compared to H-ferrierite, a low selectivity to isobutene is observed for H-TNU-10. However, it is found that Co-TNU-10 exhibits a maximum NO conversion of 93% at 823 K under conditions of high concentrations of methane (16000 ppm) and water vapor (10%) and in the presence of 2.6% O-2, which is considerable higher than even the value (74%) obtained from Co-ferrierite, known as the best catalyst for this reaction, under the identical conditions. 2004-134 Mogare, KM Friese, K Klein, W Jansen, M Syntheses and crystal structures of two sodium ruthenates: Na2RuO4 and Na2RuO3 ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 630, 2004, 547-552. Na2RuO4, prepared from Na2O2 and RuO2 via high oxygen pressure synthesis, crystallises monoclinic in space group P2(1)/c (a = 10.721(6), b = 7.033(4), c = 10.871(6) Angstrom, beta = 119.10(4)degrees, Z = 8, 2503 unique reflections, R-1 = 0.049). Structure determination from single crystal data shows that the compound consists of infinite chains of RuO5 trigonal bipyramids connected through their axial vertices. The Na cations connect the pseudohexagonally packed (1)(infinity)[RuO3O2/2] chains and are coordinated by six or seven oxygen atoms, respectively. The compound exhibits an one-dimensional spin system with mu = 2.80 mu(B) and Theta = -222 K and a three-dimensional antiferromagnetic ordering below 50 K. Na2RuO3 was obtained from Na2RuO4 at 850 degreesC under a flow of argon. The structure was determined from X-ray powder diffraction. It is closely related to the alpha-NaFeO2 and the Li2SnO3 structure types, layered variants of the NaCl type. In Na2RuO3 the Na and Ru atoms are partially disordered. This partially disordered state was approximated by a Rietveld refinement of two superimposed structural models (model I: R (3) over bar m, a = 3.12360(5), c = 16.0370(4) Angstrom, Z = 2; model II: C2/c, a = 5.4141(4), b = 9.3663(6), c = 10.8481(4) Angstrom, beta = 99.636(9)degrees, Z = 8). 2004-135 ??? Zima, V Melanova, M Benes, L Trchova, M Dybal, J Intercalation of gamma-butyrolactone into vanadyl phosphate and niobyl arsenate EUROPEAN JOURNAL OF INORGANIC CHEMISTRY iss 3, 2004, 570-574. Intercalation compounds of vanadyl phosphate and isostructural niobyl arsenate with gamma-butyrolactone, VOPO4.C4H6O2 and NbOAsO4.C4H6O2, respectively, were prepared from corresponding propanol intercalates by molecular exchange in a microwave field. The prepared intercalates were characterized using powder X-ray diffraction, density measurements, and thermogravimetric analysis. Infrared and Raman spectra indicate a coordination of the carbonyl oxygen atom of the gamma-butyrolactone molecule to the vanadium or niobium atom of the host structure. Quantum mechanical calculations at the ab initio level confirm the proposed structure in which the I-butyrolactone guest molecules are arranged with the plane of the ring perpendicular to the host layers and are anchored to the layers through the carbonyl oxygen atom coordinated to the transition metal atom of the host. 2004-136 Dova, E Peschar, R Sakata, M Kato, K Stassen, AF Schenk, H Haasnoot, JG Structures of Fe-II spin-crossover complexes from synchrotron powder-diffraction data ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 60, 2004, 528-538. Crystal structure determination and analysis have been carried out for the two spin-crossover compounds [Fe(teeX)(6)](BF4)(2) (teeX is haloethyltetrazole; X = I: teei; X = Br: teeb), in both their high-spin (near 300 K) and their low-spin states (T = 90 K), using high-resolution powder-diffraction data collected at the ESRF (Grenoble, France) and SPring8 (Japan) synchrotron radiation facilities. The structures of teei have been solved using various direct-space structure determination techniques (grid search genetic, algorithm and parallel tempering) and refined with the Rietveld method using geometrical restraints. In the case of teeb, a structural model was found but a full refinement was not successful because of the presence of a significant amount of an amorphous component. Analysis of the structures (space group P2(1)/c, Z = 2) and diffraction data, and the absence of phase transitions, show the overall structural similarity of these compounds and lead to the conclusion that the gradual spin-crossovers are likely to be accompanied by small structural changes only. 2004-137 Xu, HW Nyman, M Nenoff, TM Navrotsky, A Prototype sandia octahedral molecular sieve (SOMS) Na2Nb2O6-H2O: Synthesis, structure and thermodynamic stability CHEMISTRY OF MATERIALS 16, 2004, 2034-2040. A new microporous phase Na2Nb2O6.H2O, which transforms to NaNbO3 perovskite on heating, has been synthesized by the hydrothermal method. Rietveld analysis of powder synchrotron X-ray diffraction data reveals that the structure comprises a framework of [NbO6] and [NaO6] pctahedra with other Na+ being located in the channels (space group C2/c; a = 17.0511(9) Angstrom; b = 5.0293(2) Angstrom; c = 16.4921(9) Angstrom; beta =113.942(2)degrees). This phase belongs to the recently synthesized Sandia octahedral molecular sieves (SOMS) family, Na2Nb2-xMxO6-x(OH)(x).H2O (M = Ti, Zr) and is the archetype for the substituted structures. Using drop-solution calorimetry into molten 3Na(2)O.4MoO(3) at 974 K, the enthalpies of formation of Na2Nb2O6.H2O from the constituent oxides and from the elements have been determined to be -295.4 +/- 4.8 and -2895.5 +/- 6.4 kJ/mol, respectively. From the drop-solution calorimetric data for Na2Nb2O6.H2O and its dehydrated perovskite phase, the enthalpy of the dehydration reaction, Na2Nb2O6.H2O --> 2NaNbO(3) + H2O, has been derived, and its implications for phase stability are discussed. 2004-138 Christensen, M Iversen, BB Bertini, L Gatti, C Toprak, M Muhammed, M Nishibori, E Structural study of Fe doped and Ni substituted thermoelectric skutterudites by combined synchrotron and neutron powder diffraction and ab initio theory JOURNAL OF APPLIED PHYSICS 96, 2004, 3148-3157. We present neutron and synchrotron powder-diffraction investigations as well as ab initio calculations to elucidate delicate structural features in doped skutterudites. Samples with assumed Fe doping were investigated (FeyCo4Sb12, y=0.4, 0.8, 1.0, and 1.6), as well as samples with formal Ni substitution (Co4-xNixSb12, x=0, 0.4, 0.8, and 1.2). The present study serves as a case story for the determination of fine structural details of thermoelectric skutterudites by diffraction methods in combination with ab initio calculations. We illustrate the problem of fluorescence in the conventional x-ray powder diffraction on the Fe-doped samples by a comparison with the neutron powder-diffraction data. On the series of the Ni-substituted samples, the neutron powder-diffraction data were collected to investigate the exact sitting of the Ni. The sample with the highest Ni substitution (Co2.8Ni1.2Sb12) was also used for high resolution, high-energy synchrotron powder diffraction measurements. These revealed that the sample consists of two skutterudite phases. A complete description of the Ni-substituted samples was obtained in tandem with ab initio calculations, which show that the system contains a Ni-rich (Co0.38Ni3.62Sb12) and a Ni-poor (Co3.76Ni0.24Sb12)) skutterudite phases. 2004-139 Cernak, J Gerard, F Kappenstein, C Chomic, J Copper/Zinc oxide catalysts. Part XII. Solid solution formation in the CuO/ZnO system. X-ray powder diffraction study MONATSHEFTE FUR CHEMIE 135, 2004; 1081-1088. Coordination compounds Zn(ma1)(H2O)(2) (ZMH) (mal=maleate anion (C2H2(CO2)(2)(2-))), Cu0.06Zn0.94(mal)(H2O)(2) (ZCMH), Cu(mal)(H2O) (CMH), and physical mixtures of CMH and ZMH were used as precursors for calcination experiments in air at 500 and 1000degreesC lasting 18 hours. The obtained oxides were investigated by X-ray powder diffraction technique. Calcination at 500degreesC yielded pure zincite phase (ZnO), tenorite phase (CuO), or their mixtures. The calcination of the Zn-rich sample ZCMH at 1000degreesC lead to zincite phase displaying a slightly lower cell volume than the pure zincite phase obtained from Zn-only containing precursor (ZMH). These results suggest that the assumed solid solution CuxZn1-xO (x=0.01-0.02) exhibits a solubility limit lower than the copper content in the ZCMH precursor (6 mol-%). On the other hand, the calcination of the Cu-rich samples at 1000degreesC, in the presence of Zn(II), yielded tenorite phase exhibiting cell parameters significantly different from those reported for the pure tenorite phase, due to the formation of Zn0.03Cu0.97O solid solutions. All these results are corroborated by intensity analysis of the diffraction peaks. 2004-140 Pfeffer-Hennig, S Piechon, P Bellus, M Goldbronn, C Tedesco, E Physico-chemical characterization of an active pharmaceutical ingredient - Crystal polymorphism and structural analysis JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY 77, 2004, 663-679. The physico-chemical properties and polymorphism of a new active pharmaceutical ingredient entity has been analyzed and the gain of knowledge during the chemical development of the substance is described. Initial crystallization revealed an anhydrous crystal form with good crystallinity and a single, sharp DSC melting peak at 171 degreesC and a straightforward development of this crystal form seemed possible. However, during polymorphism screening, new crystalline forms were detected that were often analyzed as mixtures of crystal forms. The process of characterization and identification of the different crystalline forms and its thermodynamical relationship has been supported by a combination of experimental and computational work including determination of the three-dimensional structures of the crystal forms. The crystal structure of one polymorphic form was solved by single crystal X-ray structure analysis. Unfortunately, Mod B resisted in formation of suitable single crystals, but its structure could be solved by high resolution powder diffraction data analysis using synchrotron radiation. Calculation of the theoretical X-ray powder diffraction pattern from three dimensional crystal coordinates allowed an unambiguous identification of the different crystalline forms. Two polymorphic crystal forms of the API-CG3, named Mod A and Mod B, are enantiotropic whereas Mod B is the most stable polymorph at room temperature up to about 50 degreesC and Mod A at temperatures above 50 degreesC. The mechanism of the solid - solid transition can be explained by analyzing the molecular packing information gained from the single crystal structures. A third crystalline form with the highest melting peak turned out to be not a polymorphic or pseudopolymorphic crystal modification of our API-CG3 but a chemically different substance. 2004-141 Schobinger-Papamantellos, P Rodriguez-Carvajal, J Andre, G Ritter, C Buschow, KHJ Re-entrant magneto-elastic transition in HoFe4Ge2 a neutron diffraction study JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 280, 2004, 119-142. The re-entrant magneto-elastic transition of the antiferromagnetic HoFe4Ge2 compound has been studied by neutron powder diffraction as a function of temperature. The magnetic phase diagram comprises the wave vectors: (q(1o), q(2o), q(1t)) and three magnetic transitions, two of them occurring simultaneously with the structural changes at T-c, T-N = 52 and T-c', T-ic1 = 15 K, the third being purely magnetic at T-ic2 = 40 K. The first transition is of second order while the latter two of first order. The sequence of phases follows the path: P4(2)/mnm (HT), T-c, T-N = 52 K --> Cmmm (IT): (q(1o) = (0, 1/2, 0) T-ic2 = 40 K double right arrow q(2o) = (0, q(y), 0)), T-c', T-ic1 = 15 K double right arrow P4(2)/mnm (LT): q(1t) = (0, 1/2, 0). The magnetic structures described by the wave vectors (q(1o), q(2o) and q(1t)), where the components are referred to the reciprocal basis of the conventional Cmmm cell, correspond to canted multi-axial arrangements. The q(2o) wave vector length of the amplitude modulated phase varies non-monotonously, decreasing fast just below T-ic2,-slowly between 36K-T-c', T-ic1 and jumping to the q(1t) = (0, 1/2,0) lock-in value at T-c', T-ic1 simultaneously with the first order re-entrant transition to the (LT) tetragonal phase. In the coexisting meta-stable orthorhombic phase from T-c', T-ic1 down to 1.5 K the length of the wave vector q(2o) continues to decrease. To solve the magnetic structures of all the phases appearing in this complex situation, arising from competing ordering mechanisms and anisotropies of the underlying sublattices, we have used the simulated annealing method of global optimisation on high-resolution neutron powder diffraction data. 2004-142 Pirozzi, B Napolitano, R Petraccone, V Esposito, S Determination of the crystal structure of syndiotactic 3,4-poly(2-methyl-1,3-butadiene) by molecular mechanics and X-ray diffraction MACROMOLECULAR CHEMISTRY AND PHYSICS 205, 2004, 1343-1350. The crystal structure of syndiotactic 3,4-poly(2-methyl-1,3-butadiene) has been determined by the joint use of molecular mechanics and X-ray diffraction. Molecular mechanics calculations have been performed both on the isolated chain and on the crystal by the use of various force fields. The energy minimizations predict a model of the crystal structure. The calculated X-ray powder diffraction pattern is in good agreement with the experiment one. This model had been refined in order to obtain the best agreement with all the experimental data. The space group id Pbcm and the parameters of the unit cell are a = 6.6 Angstrom, b = 13.2 Angstrom, c = 5.27 Angstrom. The presence of defects in the crystal has been taken into account. Analogies and differences with the crystal structure of syndiotactic 1,2-poly(1,3-butadiene) are discussed. 2004-143 Weirich, TE The crystal structure of Zr2Se reinvestigated by electron crystallography and X-ray powder diffraction CRYSTALLOGRAPHY REPORTS 49, 2004, 379-389. The metal-rich compound Zr2Se is of particular interest for electron crystallography, since it was one of the first examples that proved that heavy-atom structures can be solved via quasi-automatic direct methods from selected area electron diffraction intensities [1]. For this reason, Zr2Se has been chosen as a model to discuss the possibilities and the limits of the quasi-kinematical approach that has been successfully used to determine this and related structures from high-resolution electron microscopy (HREM) images and selected area electron diffraction. In order to quantify the achievable accuracy of the electron crystallography techniques used, the corresponding structures are compared with results from structural analysis with X-ray powder data and with a model received from first-principles calculations. The latter structure was chosen in this study as a reference, since the calculations do not depend on experimental parameters. Analysis of the obtained result from electron diffraction structural analysis (EDSA) shows that the structural model is, on average, only off by 0.08 Angstrom, despite the investigated crystal having an effective thickness of 286 Angstrom. The corresponding result from Rietveld refinement with X-ray powder data agrees to within 0.04 Angstrom with the structure from calculation and within 0.03 Angstrom with the result from an earlier single crystal X-ray study [2]. 2004-144 Rius, J Elkaim, E Torrelles, X Structure determination of the blue mineral pigment aerinite from synchrotron powder diffraction data: The solution of an old riddle EUROPEAN JOURNAL OF MINERALOGY 16, 2004, 127-134. The structure of aerinite, a blue fibrous silicate mineral associated with the alteration of ophitic rocks in the southern Pyrenees, has been determined by applying the direct methods modulus sum function to synchrotron powder diffraction data. This mineral was the blue pigment commonly used in most Catalan romanic paintings between the XI-XV centuries. The studied specimen comes from the Camporrells-Estopanya area (Huesca, Spain). The unit cell dimensions are a = b = 16.8820(9), c = 5.2251(3) Angstrom, the space group is P3c1 and the structural formula is (Ca5.1Na0.5)(Fe3+AlFe2+ Mg-1.7(0.3))(Al5.1Mg0.7) [Si12O36(OH)(12)H].[(CO3)(1.2)(H2O)(12)] With Z = 1 and D-c = 2.52 g/cm(3) (Fe2+/Fe3+ ratio from Mossbauer spectroscopy; carbonate content confirmed by infrared spectroscopy). The model of the structure obtained by direct methods was refined with the Rietveld method to the residual value R-wp = 0.0937 (chi(2) = 1.05). A bond valence analysis shows the plausibility of the refined model. The crystal structure of aerinite can be best understood by introducing cylindrical basic building units consisting on three pyroxene chains pointing inwards to accommodate tri- and divalent metal cations at the centres of the resulting face-sharing octahedra. The average composition of these cationic sites is Fe3+ (0.25),Al3+ (0.25),Fe2+ (0.43),Mg2+ (0.07), the mean cation-oxygen bond length is 2.054(9) Angstrom and the intercationic distance is 2.61 Angstrom. Out of the three symmetry-independent three-fold rotation axes in the unit cell, two are occupied by such cylindrical units and the third by CO3 groups. Consequently, each unit is surrounded by three similar ones which are, however, shifted by 0.93 Angstrom along c. Between two such units, i.e., tangential to both cylindrical envelopes, a four-row wide slab of a brucite-like layer is found. The two inner octahedra are predominantly filled with Al and Mg atoms, the two outer with Ca, Na and some vacancies [average values: d(Al-O) = 1.936(53) Angstrom (6x), angle(O-Al-O) = 90.1(6.5)degrees (12x) and 172.7(4.1)degrees (3x); d(Ca-O) = 2.42(6) Angstrom (6x), angle(O-Ca-O) = 90(23)degrees (12x) and 158(14)degrees (3x)]. The internal O atoms of the brucite-like layer are hydroxyl groups, the intermediate are unshared basal O atoms of the neighbouring pyroxene chains, while the external ones are water molecules forming relatively strong H-bridges with the partially disordered CO3 groups. Presumably, the hydroxyl groups in the brucite-like layer also form H-bridges with the apical O atoms of the neighbouring pyroxene chains to compensate for the defect of charge caused by the presence of divalent cations in the face-sharing octahedra. 2004-145 Sainz-Diaz, CI Villacampa, A Otalora, F Crystallographic properties of the calcium phosphate mineral, brushite, by means of First Principles calculations AMERICAN MINERALOGIST 89, 2004, 307-313? A crystalline form of hydrated calcium phosphate, brushite (CaHPO(4)(.)2H(2)O), has been studied by means of total energy First Principles calculations based on the Density Functional Theory (DFT) approximation. The experimental crystal lattice parameters of this mineral have been reproduced with good agreement. The powder X-ray diffraction pattern simulated from the calculated crystal structure is similar to the experimental one. The intermolecular interactions within the crystal, electrostatic and hydrogen bond interactions, have been reproduced. The calculated crystal structure reproduces the atomic distribution along the (010) surface observed by high resolution scanning force microscope (SFM). The optimized crystal structure describes the different interatomic interactions along the [101], [201], and [001] directions on the (010) plane. Quantum-mechanical calculations of the energy of these surfaces confirm the experimental behavior, justifying the different crystal growth rates of these directions found experimentally. 2004-146 Du, HL Han, JZ Zhang, WY Wang, CS Wang, WC Liu, SQ Chen, HY Zhang, XD Yang, YC Determination of the zirconium site in zirconium-substituted Nd(Fe,Mo,Zr)(12) compounds JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 283, 2004, 316-321. The NdFe10.5Mo1.5-xZrx (x = 0.25,0.50) and Nd0.5Pr0.5Fe10.5-xMo1.5Zrx (x = 0, 0.25, 0.75, and 1.00) intermetallic compounds with ThMn12-type structures were successfully synthesized. Their structures were investigated by using powder X-ray diffraction. It is found that Zr is incorporated as a substituent for Nd/Pr in the structure of the two series, and the occupation of Zr is influenced by the prepared composition of Fe and the third element Mo. The effects of Zr on the magnetic properties were also studied. 2004-147 Breza, M Biskupic, S On the structure of tetralead(II) complexes with OH bridges COLLECTION OF CZECHOSLOVAK CHEMICAL COMMUNICATIONS 69, 2004, 2045-2054. Using Hartree-Fock, B3LYP and MP2 treatments, the optimal geometries and corresponding electronic structures of tetrahedral [Pb-4(mu(3)-OH)(n)](q) and [Pb4O(mu(3)-OH)(n)](q-2) complex cations with total charges q = 8 - n, n = 2, 3, 4, are investigated. After OH- removal, the central oxygen atom in [Pb4O(mu(3)-OH)(4)](2+) is shifted to the apical position in [Pb4O(mu(3)- OH)(3)](3+) whereas the [Pb-4(mu(3)-OH)(2)](6+) and [Pb4O(mu(3)-OH)(2)](4+) complex cations are unstable. Direct Pb-Pb and O-O interactions are weakly antibonding in all the systems under study. The clusters are held together exclusively by relatively weak Pb-O bonds. A higher stability of the complex cations with a larger number of OH- bridges may be confirmed. 2004-148 Breza, M Biskupic, S On the structure of boat-shaped hexalead(II) cations with OH bridges COLLECTION OF CZECHOSLOVAK CHEMICAL COMMUNICATIONS 69, 2004, 2055-2067. Using Hartree - Fock, B3LYP, and MP2 treatments, the optimal boat-shaped geometries and corresponding electronic structures of [Pb6Om(mu(3)-OH)(n)](q) complex cations with total charges q = 12 - 2m - n, m = 0 or 1, n = 6 or 8, are investigated. Whereas the [Pb-6(mu(3)-OH)(6)](6+) cation is unstable, the remaining structures preserve C-2v symmetry. Direct Pb - Pb interactions are weakly antibonding in all the systems under study. The clusters are held together exclusively by relatively weak Pb - O bonds. The effects of central O and two additional mu(3)-OH bridges in [Pb6O(mu(3)-OH)(8)](2+) are not fully cooperative. [Pb6O(mu(3)-OH)(6)](4+) and [Pb-6(mu(3)-OH)(8)](4+) may coexist in water solutions in comparable concentrations. 2004-149 Laco, JII Crystal structures of poly(n-methylen-di-O-methyl-L-tartaramide)s with n=3, 5, 7 and 9 POLYMER 45, 2004, 7025-7033 The structural characterization of poly(n-methylen-di-O-methyl-L-tartaramide)s with n = 3, 5, 7 and 9 has been carried out using optical microscopy, thermal analysis, X-ray diffraction and electron microscopy. X-ray diffraction of powder and fiber samples were analyzed together with electron diffraction patterns of single crystals obtained from isothermal crystallization in solution. Experimental results based on crystallographic data were used to build a crystal model using the Cerius program. This model is based in chain packing with an arrangement of hydrogen-bonded sheets, being the resultant crystal structure similar to the exhibited in conventional polyamides. 2004-150 Abakumov, AM Rozova, MG Chizhov, PS Antipov, EV Hadermann, J Van Tendeloo, G Synthesis and crystal structure of the novel Pb5Sb2MnO11 compound JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 2855-2861. The new Pb5Sb2MnO11 compound was synthesized using a solid-state reaction in an evacuated sealed silica tube at 650degreesC. The crystal structure was determined ab initio using a combination of X-ray powder diffraction, electron diffraction and high-resolution electron microscopy (a = 9.0660(8) Angstrom, b = 11.489(1) Angstrom, c = 10.9426(9) Angstrom, S.G. Cmcm, R-1 = 0.045, R-P = 0.059). The Pb5Sb2MnO11 crystal structure represents a new structure type and it can be considered as quasi-one-dimensional, built up of chains running along the c-axis and consisting of alternating Mn+2O7 capped trigonal prisms and Sb2O10 pairs of edge sharing Sb+5O6 octahedra. The chains are joined together by Pb atoms located between the chains. The Pb+2 cations have virtually identical coordination environments with a clear influence of the lone electron pair occupying one vertex of the PbO5E octahedra. Electronic structure calculations and electron localization function distribution analysis were performed to define the nature of the structural peculiarities. Pb5Sb2MnO11 exhibits paramagnetic behavior down to T = 5K with Weiss constant being nearly equal to zero that implies lack of cooperative magnetic interactions. 2004-151 Brize, V Georges, S Kodjikian, S Suard, E Goutenoire, F La6Mo8O33: a new ordered defect Scheelite superstructure JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 2617-2627. The structure of La6Mo8O33 has been determined from a triple pattern powder diffraction analysis. Two high-resolution neutron diffraction patterns collected at 1.594 and 2.398 Angstrom and one X-rays were used. This molybdate crystallizes in a non-centrosymmetric monoclinic space group P2(1) (Ndegrees4), Z = 2, a = 10.7411(3) Angstrom, b = 11.9678(3) Angstrom, c = 11.7722(3) Angstrom, beta = 116.062 (1)degrees. La6Mo8O33 is an unusual ordered defect Scheelite. Hence, it should be described with cation vacancies and an extra oxygen atom following the formula: La(6)rectangle(2)Mo(8)O(32+1). This extra oxygen atom leads to a pyramidal environment, whereas the other molybdenum atoms present tetrahedral environment. A molybdenum tetrahedral is connecting to the pyramid, forming an [Mo2O9] unit. 2004-152 Kamegashira, N Satoh, H Meng, J Mikami, T Structural determination of a new phase of monoclinic BaTb2Mn2O7 JOURNAL OF ALLOYS AND COMPOUNDS 374, 2004, 173-176. A new phase of monoclinic BaTb2Mn2O7 with extra superlattice lines in addition to the usual orthorhombic X-ray diffraction patterns was prepared and a Rietveld refinement was applied to analyze the crystal structure using X-ray powder diffraction data at room temperature. The refined lattice parameters were a = 0.54918(8) nm, b = 2.0149(5) nm, c = 0.54922(9) nm, and beta = 90.62degrees with the space group A2/m (no. 12). The MnO6 oxygen octahedron has distortion and tilts around a-axis by about 7degrees each other in the reverse direction. 2004-153 Perchiazzi, N Gualtieri, AF Merlino, S Kampf, AR The atomic structure of bakerite and its relationship to datolite AMERICAN MINERALOGIST 89, 2004, 767-776. Four samples of bakerite, Ca4B5Si3O15(OH)(5), were studied by means of IR, TG/DSC, EPMA, and X-ray and neutron diffraction. Chemical analyses can readily discriminate bakerite from datolite, Ca4B4Si4O16(OH)(4), by the distinctly lower SiO2 content of the former. The Rietveld refinement of the combined neutron and X-ray powder data allow the determination of the crystal structure of bakerite to R-p 3.09%. The crystal structure can be derived from that of datolite by the substitution 0.25Si(4+) + 0.25O(2-) <----> 0.25B(3+) + 0.25(OH)(-) at the Si-centered tetrahedral site. This leads to the crystal chemical formula Ca(4)B(5)Si(3)0O(15)(OH)(5). Both of the two hydrogen positions in the bakerite structure, one with full occupancy, the other with 25% occupancy, were precisely located. The water molecule generally thought to be present in bakerite structure is actually absent. The excess water detected in chemical analyses can be attributed to the presence of minor impurities. Given the consistent composition of bakerite from various localities and no evidence for Substitution of B for Si in datolite, bakerite is retained as a distinct species. A possible explanation of the peculiar 5:3 boron to silicon ratio in bakerite is provided. 2004-154 Patoux, S Rousse, G Leriche, JB Masquelier, C Crystal structure and lithium insertion properties of orthorhombic Li2TiFe(PO4)(3) and Li2TiCr(PO4)(3) SOLID STATE SCIENCES 6, 2004, 1113-1120. The crystal structures of orthorhombic Li2TiFe(PO4)(3) and Li2TiCr(PO4)(3) were determined from Rietveld refinement of neutron powder diffraction data. Both compounds are isostructural in the Pbna space group with a = 8.543(1) Angstrom, b = 8.623(1) Angstrom, c = 11.978(1) Angstrom and a = 8.505(1) Angstrom, b = 8.589(1) Angstrom, c = 11.929(1) Angstrom, respectively. Lithium ions are located in a single four-fold coordinated site Li(1). Electrochemical insertion of lithium proceeds through the reduction of Fe3+ into Fe2+ (similar to 2.8 V vs. Li+/Li) and Ti4+ into Ti3+ (similar to 2.5 V vs. Li+/Li) towards the new compositions Li3TiCr(PO4)(3) and Li4TiFe(PO4)(3). In situ X-ray diffraction and potentiostatic intermittent titration technique indicate a solid solution mechanism for the reversible lithium insertion/extraction. Chemical reaction of Li2TiFe(PO4)3 with n-BuLi leads to orthorhombic Li4TiFe(PO4)3. 2004-155 Wallez, G Launay, S Quarton, M Dacheux, N Soubeyroux, JL Why does uranium oxide phosphate contract on heating? JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 3575-3580. (U2O)(PO4)(2) is related to ultra-low expansion beta-(Zr2O)(PO4)(2) ceramics, but shows a continuous thermal contraction. High-temperature neutron diffraction has allowed to follow accurately the thermal variations of its cell edges and to give a structural explanation to the phenomenon: like in beta-(Zr2O)(PO4)(2), the dilatometric anomaly arises simultaneously from a contractive push-pull effect due to Coulombic repulsions and from a libration of the PO4 and UO7 polyhedra, but in the present case, the second mechanism predominates. The size of the tetravalent cation appears as a key parameter in monitoring the thermal expansion of ceramics of this family. 2004-156 Yan, W Lerner, MM Synthesis and structural investigation of new graphite intercalation compounds containing the perfluoroalkylsulfonate anions C10F21SO3-, C2F5OC2F4SO3-, and C2F5(C6F10)SO3- CARBON 42, 2004, 2981-2987. The preparation of graphite intercalation compounds (GIC's) of three perfluorinated alkylsulfonate anions, C10F21SO3-, C2F5OC2F4SO3- and C2F5(C6F10)SO3- is described for the first time. Pure stage 2 GIC's are obtained by chemical oxidation of graphite with K2MnF6 in a solution containing hydrofluoric and nitric acids for 72 h. One-dimensional electron density maps derived from powder diffraction data are fit to obtain models for the intercalate gallery structures: the structure models provide details on anion concentrations, orientations, and conformations. In all cases, anion bilayers are observed with anion sulfonate headgroups oriented towards graphene sheets. Compared with structures calculated for the isolated anions, the intercalated anion conformations show changes in dihedral angles, involving rotations about C-C or C-O bonds. For the GIC containing C2F5(C6F10)SO3-, the anion conformation change is related to the more efficient packing of anions in the intercalate gallery. 2004-157 Tremayne, M Direct space structure solution applications JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 109, 2004, 49-63. The crystal structures of 2,4,6-triisopropyl-benzenesulfonamide, 1,2,3-trihydroxybenzenehexamethylenetetramine (1/1), 5-bromonicotinic acid and chlorothalonil form II have been solved from x-ray powder diffraction data, by application of a direct space structure solution approach using the Monte Carlo method and confirmed by Rietveld refinement. In the sulfonamide, the molecules are linked by N - H...O hydrogen bonds into two-dimensional sheets built from alternating eight and twenty-membered rings. In the cocrystal, the molecules are linked by O-H...N hydrogen bonds to form puckered molecular ribbons that are in turn linked into a continuous 3D framework by C-H...pi ( arene) interactions. 5-bromonicotinic acid also displays atypical hydrogen-bonding behaviour by formation of dimers through a self-complementary acid-acid hydrogen-bond motif that are connected into antiparallel ribbons by C - H...O and C - H...N hydrogen bonds. Structure determination of the cocrystal and the bromonicotinic acid was successful despite the presence of preferred orientation in the data, whereas the distortion of the chlorothalonil data was so severe that structure solution was only possible when the effects of preferred orientation were minimized. Both the disordered structure, and an ordered structural approximation of chlorothalonil form II have been determined and rationalized. 2004-158 ??? Siwicka, A Reiter, RJ Tian, DX Wojtasiewicz, K Leniewski, A Maurin, JK Blachut, D Czarnocki, Z The synthesis and the structure elucidation of N,O-diacetyl derivative of cyclic 3-hydroxymelatonin CENTRAL EUROPEAN JOURNAL OF CHEMISTRY 2, 2004, 425-433. Melatonin was subjected to an oxidation to give 3-hydroxymelatonin. All spectroscopic data for this compound were collected. Ab initio calculations for both possible configurations were performed. X-ray data on N, O-diacetyl derivative of 3-hydroxymelatonin allowed the unambigous structure determination. 2004-159 Muhle, C Karpov, A Nuss, J Jansen, M Crystal growth and crystal structure determination of K-2[Pt(CN)(4)Cl-2], K-2[Pt(CN)(4)Br-2], K-2[Pt(CN)(4)I-2] and K-2[Pt(CN)(4)]Cl-2]center dot 2H(2)O ZEITSCHRIFT FUR NATURFORSCHUNG SECTION B-A JOURNAL OF CHEMICAL SCIENCES 59, 2004, 567-572. Crystals of K2Pt(CN)(4)Br-2, K2Pt(CN)(4)I-2 and K2Pt(CN)(4)Cl(2)(.)2H(2)O were grown, and their crystal structures have been determined from single crystal data. The structure of K2Pt(CN)(4)Cl-2 has been determined and refined from X-ray powder data. All compounds crystallize monoclinicly (P2(1)/c; Z = 2), and K2Pt(CN)(4)X-2 with X = Cl, Br, I are isostructural. K2Pt(CN)(4)Cl-2: a = 708.48(2); b = 903.28(3); c = 853.13(3) pm; beta = 106.370(2)degrees; R-p = 0.064 (N(hkl) = 423). K2Pt(CN)(4)Br-2: a = 716.0(1); b = 899.1(1); c = 867.9(1) pm; beta = 106.85(1)degrees; R(F)(N') = 0.026 (N'(hkl) = 3757). K2Pt(CN)(4)I-2: a = 724.8(1); b = 914.5(1); c = 892.1(1) pm; beta = 107.56(1)degrees; R(F)(N') = 0.025 (N'(hkl) = 2197). K2Pt(CN)(4)Cl-2 (.) 2H(2)O: a = 763.76(4); b = 1143.05(6); c = 789.06(4) pm; beta = 105.18(1)degrees; R(F)(N') = 0.021 (N'(hkl) = 2281). Raman and infrared spectroscopy data are reported. 2004-160 Niewa, R Zherebtsov, DA New phases in the lithiumnitridovanadate system - The solid solution Li7-2xMgx[VN4] with 0 <= x <= 1 ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 630, 2004, 229-233. Solid solution phases Li7-2xMgx[VN4] (0 < x less than or equal to 1) with varying Mg-content are obtained as yellow microcrystalline powders from heat treatment of mixtures of VN, Li3N and Mg3N2 or from mixtures of Li-7[VN4] and Mg3N2 at 1370 K in N-2 atmosphere at ambient pressure. At substitution parameter values of x > 0.5 a subsequent distortion from the ideal cubic unit cell to an orthorhombic unit cell is observed. The crystal structure of Li7-2xMgx[VN4] with x approximate to 1 was refined from neutron and X-ray powder diffraction data (space group Pbca, No. 61, a = 963.03(3) pm, b = 958.44(3) pm, c = 951.93(2) pm, neutron pattern 14degrees - 156degrees 2theta, step non-linear approximate to 0.0782degrees 2theta, No. of measured points 1816, R-p = 0.089, R-wp = 0.115, R-Bragg = 0.155, R-F = 0.114; X-ray pattern 10degrees - 98degrees 2theta, step 0.005degrees 2theta, No. of measured points 17600, R-p = 0.028, R-wp = 0.045, R-Bragg = 0.113, R-F = 0.133, structure variables: 45). The crystal structure resembles a Li2O type superstructure with the atomic arrangement of beta-Li-7[VN4] and with two crystallographic Li-sites each substituted by Mg with statistical occupation factors of 0.5. Chemical analyses prove the composition and XAS spectroscopy at the V K-edge support the +5 oxidation state assignment for vanadium. XAS data also support the tetrahedral coordination of vanadium by N as indicated by the structure refinements. 2004-161 Le Berre, F Crosnier-Lopez, MP Fourquet, JL Cationic ordering in the new layered perovskite BaSrTa2O7 SOLID STATE SCIENCES 6, 2004, 53-59. BaSrTa2O7 is a new well-ordered layered perovskite synthesized by solid state reaction. This phase derives from the Dion-Jacobson family of general formula A'[A(n-1)B(n)O(3n+1)] with B =Ta and n =2 in which the monovalent cation A' is replaced by one divalent cation. The structure was refined from X-ray powder diffraction data in the orthorhombic space group Immm (No. 71) with lattice constants a = 3.99372(5) Angstrom, b = 7.8428(1) Angstrom and c = 20.1609(3) Angstrom (Z = 4). Although the similar Sr-O and Ba-O distances allow the localization inside or between the perovskite blocks for the two cations, the X-ray study reveals that the Ba2+ and Sr2+ ions are strictly ordered: Ba2+ ions in an interlayer position (4j site) and Sr2+ ions within the perovskite blocks (2b and 2c sites). TEM study is undertaken to verify the local Ba2+/Sr2+ distribution (local ordering or population fluctuations) and to check the possible existence of other n members. 2004-162 Ferey, G Serre, C Mellot-Draznieks, C Millange, F Surble, S Dutour, J Margiolaki, I A hybrid solid with giant pores prepared by a combination of targeted chemistry, simulation, and powder diffraction ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 43, 2004, 6296-6301. 2004-163 Brodski, V Peschar, R Schenk, H Brinkmann, A van Eck, ERH Kentgens, APM Coussens, B Braam, A Structure of melaminium dihydrogenpyrophosphate and its formation from melaminium dihydrogenphosphate studied with powder diffraction data, solid-state NMR, and theoretical calculations JOURNAL OF PHYSICAL CHEMISTRY B 108, 2004, 15069-15076. Melaminium dihydrogenpyrophosphate (bis(2,4,6-triamino-1,3,5-triazinium dihydrogenpyrophosphate, MPy), obtained as a crystalline powder by thermal treatment of melaminium dihydrogenphosphate (MP), is the first intermediate in the synthesis of polymerized melamine phosphates that are used as environmental-friendly flame retardants. The crystal structure of MPy was determined by X-ray powder diffraction and the proposed hydrogen-bonding model was corroborated by solid-state NMR and periodic DFT calculations. A mechanism is proposed for the endothermic dehydration process that takes place in the reaction from MP to MPy, in accordance with energy calculations based on the optimized crystal structures of MPy and MP. A packing analysis of MPy and other melamine-containing compounds revealed some typical melamine packing motifs. 2004-164 Schenk, H Peschar, R Understanding the structure of chocolate RADIATION PHYSICS AND CHEMISTRY 71, 2004, 829-835. Crystallization of cocoa-butter in the beta phase from the melt under static conditions is only possible using the memory effect of cocoa-butter. Under all other conditions polymorphs with lower melting temperatures develop, whereas the beta phase is the preferred one in chocolate. SAXS experiments proved 1,3-distearoyl-2-oleoylglycerol seeds with triple chain-length packing initiate the beta-crystallization. Models for the different phases may be based on the crystal structure determinations of triacylglycerols. A new, patented, way of chocolate making is in development in which the traditional tempering process is replaced by another pre-crystallization process. The process is based on the use of seed crystals in the liquid phase and driven by a feedback system. 2004-165 De Ridder, DJA Goubitz, K Brodski, V Peschar, R Schenk, H Crystal structure of melaminium orthophosphate from high-resolution synchrotron powder-diffraction data HELVETICA CHIMICA ACTA 87, 2004, 1894-1905. The crystal structure of melaminium orthophosphate (MP) has been determined from high-resolution synchrotron powder-diffraction data. The crystal packing consists of melaminium layers and pairs of orthophosphate chains connected by H-bonds almost perpendicular to the layers. The distance between melaminium layers is 3.62 Angstrom. Neighboring melaminium molecules do not lie in the same plane, but in two parallel planes at close distance (0.79 Angstrom), and are shifted with respect to each other. The orthophosphate chains are connected by both intra-chain and inter-chain H-bonds. The melamine is singly protonated at an endocyclic N-atom. The powder-diffraction data were corroborated by solid-state NMR experiments. 2004-166 Vos, TE Liao, Y Shum, WW Her, JH Stephens, PW Reiff, WM Miller, JS Diruthenium tetraacetate monocation, [Ru-II/(III)(2)(O2CMe)(4)](+), building blocks for 3-D molecule-based magnets JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 126, 2004, 11630-11639. Diruthenium tetracarboxylates monocations are utilized as building blocks for cubic 3-D network structured molecule-based magnets. [Ru-2(II/III)(O2CMe)(4)](3)[M-III(CN)(6)] [M = Cr (1a), Fe (2), Co (3)] were prepared in aqueous solution. Powder X-ray diffraction indicates that they have body-centered cubic structures (space group = lm (3) over barm, a = 13.34, 13.30, and 13.10 Angstrom for 1a, 2, and 3, respectively), which was confirmed for 1a by Reitveld analysis of the synchrotron powder data [a = 13.3756(5) Angstrom]. [Ru-2(O2CMe)(4)](3)[M-III(CN)(6)](.)xMeCN [M = Cr, x = 1.8 (1b); M = Mn, x = 3.3 (4)] were prepared from acetonitrile. The magnetic ordering of 1a (33 K), 1b (34.5 K), 2 (2.1 K), and 4 (9.6 K) was determined from the temperature dependencies of the in-phase (chi') alternating current (AC) susceptibility. The field dependence of the magnetization, M(H), at 2 K for 1a showed an unusual constricted hysteresis loop with a coercive field, H-cr, of 470 Oe while the 10(h) data for 1b, 2, and 4 showed a normal hysteresis loop with a coercive field of 1670, 10, and 990 Oe, respectively. The Fe-57 Mossbauer spectrum of 2 is consistent with the presence of low spin Fe-III (6 = -0.05 mm/s; DeltaE = 0.33 mm/s) at room temperature, and the onset of 3-D magnetic ordering at lower temperature (<2 K). The effects of M-III in [M-III(CN)(6)](3-), and the large zero-field splitting (D) of diruthenium tetracarboxylates are discussed. The increasing critical temperatures T-c, with increasing S could not be accounted for by mean field models without significantly different J values for 1a, 4, and 2. By fitting the T-c data with mean field models [H = -2JS(Ru)(.)S(M) - mu(B)(g(Ru)S(Ru) + g(M)S(M))(H)], J/k(B) are 4.46, 1.90, and 0.70 K for 1a, 4, and 2, respectively. 2004-167 Mazina, OS Rybakov, VB Chernyshev, VV Babaev, EV Aslanov, LA X-ray mapping in heterocyclic design: XIV. Tricyclic heterocycles based on 2-oxo-1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile CRYSTALLOGRAPHY REPORTS 49, 2004, 998-1009. The structures of four compounds are studied using single-crystal X-ray diffraction: 1-[2-(4-chlorophenyl)-2-oxoethyl]-2-oxo-1,2,5,6,7,8-hexahydroquinoline-3 -carbonitrile [a = 4.908(4) Angstrom, b = 11.644(10) Angstrom, c = 13.587(2) Angstrom, beta = 94.31(5)degrees, Z = 2, space group P2(1)]; 2-[2-(4-chlorophenyl)-2-oxoethoxy]-5,6,7,8-tetrahydroquinoline-3-carboni trile [a = 7.6142(8) Angstrom, b = 14.778(2) Angstrom, c = 14.132(2) Angstrom, beta = 100.38(1)degrees, Z = 4, space group P2(1)/c]; 4-(aminocarbonyl)-2-(chlorophenyl)-6,7,8,9-tetrahydro[1.3]oxazolo[3,2-a] quinolin-3-ium perchlorate [a = 5.589(7) Angstrom, b = 24.724(15) Angstrom, c = 13.727(5) Angstrom, beta = 97.66(9)degrees, Z = 4, space group P2(1)/n]; and (3-amino-5,6,7,8-tetrahydrofuro[2,3-b]quinolin-2-yl)-(4-chlorophenyl) methanone [a = 7.150(2) Angstrom, b = 7.4288(10) Angstrom, c = 15.314(3) Angstrom, alpha. = 98.030(10)degrees, 99.21(2)degrees, gamma = 105.34(2)degrees, Z = 2, space group P (1) over bar]. The structures are solved by direct methods and refined by the full-matrix least-squares procedure in the anisotropic approximation to R = 0.0728, 0.0439, 0.1228., and 0.0541, respectively. The structure of 1-(4-chlorophenyl)-4-piperidin-1-yl-8,9-dihydro-7H-pyrrolo[3.2.1-ij]quin oline-5-carboxamide [a = 23.9895(9) Angstrom, b = 5.1557(3) Angstrom, c = 17.0959(9) Angstrom, 0 = 106.43degrees, Z = 4, space group P-1/c] is investigated by X-ray powder diffraction. This structure is solved using the grid search procedure and refined by the Rietveld method to R-wp = 0.0773, R-exp= 0.0540, R-p = 0.0585, R-b = 0.1107, and chi(2) = 1.78. 2004-168 Al'bov, DV Mazina, OS Rybakov, VB Babaev, EV Chernyshev, VV Astanov, LA X-ray mapping in heterocyclic design: XII. X-ray diffraction study of 2-pyridones containing cycloalkane fragments annelated to the C(5)-C(6) bond CRYSTALLOGRAPHY REPORTS 49, 2004, 158-168. The structures of 4,6-dimethyl-1H-pyridin-2-one [a = 6.125(2) Angstrom, b = 15.153(4) Angstrom, and c = 14.477(4) Angstrom, Z = 8, space group Pbca], the 2 : 1 : 1 complex of 4-methyl-1,5,6,7-tetrahydro-2H-cyclopenta[b]pyridin-2-one with phosphoric acid and methanol [a = 11.181(2) Angstrom, b = 14.059'(6) Angstrom, c = 13.593(4) Angstrom, beta = 97.78(2)degrees, Z = 8, space group P2(1)/n], 4-methyl-1,5,6,7,8,9-hexahydro-2H-cyclohepta[b]pyridin-2-one [a = 12.565(6) Angstrom, b = 5.836(6) Angstrom, c = 13.007(3) Angstrom, beta = 93.10(3)degrees, Z = 4, space group P2(1)/n], and 4-methyl-5,6,7,8,9,10-hexahydrocycloocta[b]pyridin-2(1H)-one [a = 12.955(3) Angstrom, b = 6.1595(15) Angstrom, c = 13.038(3) Angstrom, beta = 95.50(2)degrees, Z= 4, space group P2(1)/n] are determined b single-crystal X-ray diffraction. The structures are solved by direct methods and refined by the full-matrix least-squares procedure in the anisotropic approximation to R = 0.0755, 0.0644, 0.0754, and 0.0569, respectively. The structures of 4-methyl- 1,5,6,7-tetrahydro-2H-cyclopenta[b]pyridin-2-one [a = 7.353(4) Angstrom, h = 8.176(4) Angstrom, c = 13.00(1) Angstrom, beta = 195.64(2)degrees, Z = 4, space group P2(1)/c] and 2-oxo-1,2,5,6,7,8-hexahydroquinoline-3-carbonitrile [a = 5.9870(2) Angstrom, b = 16.5280(5) Angstrom, c = 9.6540(3) Angstrom, beta = 111.52(4)degrees, Z = 4, space group P2(1)/c] are studied by the powder diffraction technique. The structures are solved using the grid search procedure and refined by the Rietveld method to R-wp = 0. 108 and 0.058 R-exp = 0.032 and 0.027, R-p = 0.076 and 0.043, R-b = 0. 123 and 0.077, and chi(2) = 7.9 and 3.64, respectively. In all the structures, hydrogen bonds involving the N, H, and 0 atoms of the pyridone fragment are formed. 2004-169 Bouznik, VM Kirik, SD Solovyov, LA Tsvetnikov, AK A crystal structure of ultra-dispersed form of polytetrafluoroethylene based on X-ray powder diffraction data POWDER DIFFRACTION, 19, 2004, 219-224. An X-Ray powder diffraction study of ultra-dispersed polytetrafluoroethylene was carried out. As well as a regular polytetrafluoroethylene the ultra-dispersed form contents a high proportion of the crystalline phase. The X-ray diffraction pattern could be described with two-dimensional hexagonal unit cell [a =5.685(i) angstrom, symmetry group p6mm]. Structural modeling with a continuous electron density approach as well as with a discrete disordered atoms distribution was accomplished. The model was refined using the Rietveld method. The structure is characterized by a spiral arrangement of polymers (CF2-)(n) along the z-axis with complete mutual disordering by rotational displacement around z, as well as a partial molecular translation along the z-axis. Molecular disordering results in a systematic absence of reflections with 1 not equal 0 and as a sequence in two-dimensional unit cell effect. The presence of complete rotational disordering distinguishes the ultra-dispersed form of polytetrafluoroethylene from the standard one (fluoroplast-4), where only partial disordering is observed. 2004-170 Muccini, M Loi, MA Kenevey, K Zamboni, R Masciocchi, N Sironi, A Blue luminescence of facial tris(quinolin-8-olato)aluminum(III) in solution, crystals, and thin films ADVANCED MATERIALS 16, 2004, 861-864. 2004-171 Barea, E Navarro, JAR Salas, JM Masciocchi, N Galli, S Sironi, A Mineralomimetic sodalite- and muscovite-type coordination frameworks. Dynamic crystal-to-crystal interconversion processes sensitive to ion pair recognition JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 126, 2004, 3014-3015. 2004-172 Bonnet, PA van de Streek, J Trask, AV Motherwell, WDS Jones, W The crystal structure of an unstable polymorph of beta-D-allose CRYSTENGCOMM 6, 2004, 535-539. The crystal structure of a new polymorph, Form II, of beta-D-allose has been determined by X-ray powder diffraction. The unit cell is hexagonal, a = b = 16.598 Angstrom, c = 4.856 Angstrom, alpha = beta = 90degrees, gamma = 120degrees, space group P6(2) with Z = 6, Z' = 1. The molecule adopts the C-4(1) chair-conformation, with a torsional change of conformation of the O6 side-chain compared to the orthorhombic Form I. The two polymorphs share a common feature of a stacked hydrogen bonded column of molecules in the short axis direction. The structures differ in hydrogen linking of these columns. The more stable Form I has more immediate neighbours linked by hydrogen bonds to a reference molecule, and higher crystal density than Form II. 2004-173 2003-1 Keller, HL Wimbert, L On coinage metal mercury chalcogenide halides. III. On the crystal structure of Ag2HgSI2 ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 629, 2003, 2337-2340. Ag2HgSI2, was obtained as a yellow powder by heating a mixture of AgI and alpha-HgS at 120degreesC. The compound crystallizes in space group type Cmc2(1) with a = 1384.35(6) pm, b = 746.97(3) pm, c = 710.29(3) pm and Z = 4. The structure consists of a distorted hexagonal closed package of sulphur and iodine, in which a third of the tetrahedral spaces is occupied by silver and a third of the octahedral spaces is occupied by mercury. The distortion of the hexagonal structure is caused by the need of space of the lone pairs at sulphur and iodine. This was shown by the calculation of the electron localisation function (ELF). TREOR 2003-2 ?? Petrova, SA Mar'evich, VP Zakharov, RG Selivanov, EN Chumarev, VM Udoeva, LY Crystal structure of zinc calcium oxysulfide DOKLADY CHEMISTRY 393, 2003, 255-258. TREOR 2003-3 Pompetzki, M Dinnebier, RE Jansen, M Sodium dithiophosphate(V): Crystal structure, sodium ionic conductivity and dismutation SOLID STATE SCIENCES 5, 2003, 1439-1444. Na3PO2S2 was synthesized from the corresponding undecahydrate by freeze-drying. It dismutates at temperatures above 350 C into Na3PO3S and Na3POS3. The crystal structure of Na3PO2S2 was determined from X-ray powder diffraction data, and refined using the Rietveld technique (Pbca, a = 17.5359(2) Angstrom, b = 11.3044(1) Angstrom, c = 5.8656(1) Angstrom, R-F2 = 8.45%, R-p = 4.80%, R-wp = 6.79%). The baricenters of the PO2S2-tetrahedra are arranged in the sense of a hexagonal close packing. One of the P-O bonds of these tetrahedra is oriented parallel to the crystallographic c-axis with the POS2-groups in an eclipsed mutual orientation. The crystal structure of Na3PO2S2 displays a close relationship to the ones of Ca3CrN3 and Na3POS3. Above 330 degreesC, Na3PO2S2 can be regarded as a fast ionic conductor (with sigma > 10(-5) S cm(-1)). TREOR 2003-4 Fukuda, K Fukutani, K Crystal structure of calcium zirconium diorthophosphate, CaZr(PO4)(2) POWDER DIFFRACTION 18, 2003, 296-300. The crystal structure of CaZr(PO4)(2) was determined from conventional X-ray powder diffraction data using direct methods, and it was further refined by the Rietveld method. The structure was orthorhombic (space group P2(1)2(1)2(1), Z = 4) with a = 1.44876(4), b = 0.67213(1), c = 0.62347(2) nm, and V = 0.60710(3) nm(3). Final reliability indices were R-wp = 6.49%, R-B = 2.43%, and S = 1.32. The Ca atom is sevenfold coordinated, and the Ca atom and surrounding oxygen atoms form a distorted capped octahedron with a mean Ca-O distance of 0.243 nm. The ZrO7 coordination polyhedron is a distorted pentagonal bipyramid with a mean Zr-O distance of 0.216 nm. CaO7, ZrO7, and PO4 polyhedra share edges to form infinite chains with the composition [CaO(3)ZrO(3)p(2)O(8)](12-) along the [010]. Individual chains are linked together, forming a two-dimensional sheet parallel to (100). These sheets are stacked in the [100] direction to form a three-dimensional structure. TREOR 2003-5 Ferreira, A Lin, Z Soares, MR Rocha, J Ab initio structure determination of novel small-pore metal-silicates: knots-and-crosses structures INORGANICA CHIMICA ACTA 356, 2003, 19-26. Sodium chloride stannosilicate AV-13 (Na2.26SnSi3O9Cl0.26.xH(2)O) and zirconium and hafnium analogues of this material have been prepared and their structures solved from powder X-ray diffraction data using direct methods, and Na-23, Si-29 and Sn-119 solid-state NMR. AV-13 materials are small-pore solids, probably more adequately described as tunnel structures. The AV-13 framework consists of corner-sharing MO6 (M = Sn, Zr, Rf) octahedra and SiO4 tetrahedra. The latter form six-membered [Si6O18](12-) rings, which are interconnected by MO6 octahedra. The structure is better understood by considering a three-dimensional knots- and-crosses lattice. In a given layer, successive distorted-cube M-8 cages contain [Na6-x(H2O)](H2O,Cl-) octahedra (knots) and cyclohexasilicate (crosses) units. While the former are extra-framework species, the six-membered rings are, of course, part of the framework. The cages are accessed via seven-membered [M3Si4O27](26-) windows, with free aperture ca. 2.3 x 3.2 Angstrom, one per each pseudo-cube face. Pilling up layers generates the structure, with knots-and-crosses alternating. The non-framework five-coordinated Na cations are disordered. TREOR 2003-6 Burton, A Elomari, S Chen, CY Medrud, RC Chan, IY Bull, LM Kibby, C Harris, TV Zones, SI Vittoratos, ES SSZ-53 and SSZ-59: Two novel extra-large pore zeolites CHEMISTRY-A EUROPEAN JOURNAL 9, 2003, 5737-5748. The syntheses, structure solutions, and physicochemical and catalytic characterizations of the novel zeolites SSZ-53 and SSZ-59 are described. SSZ-53 and SSZ-59 were synthesized under hydrothermal conditions with the [1-(4-fluorophenyl)cyclopentylmethyl]trimethyl ammonium cation and 1-[1-(4-chlorophenyl)cyclopentylmethyl]-1-methyl azocanium cation, respectively, as structure-directing agents. The framework topology of SSZ-53 was solved with the FOCUS method, and the structure of SSZ-59 was determined by model building. Rietveld refinement of synchrotron X-ray powder diffraction data confirms each proposed model. SSZ-53 and SSZ-59 each possess a one-dimensional channel system delimited by 14-membered rings. Results from transmission electron microscopy, electron diffraction, catalytic experiments (spaciousness index and constraint index tests), and argon and hydrocarbon adsorption experiments are consistent with the proposed structures. TREOR 2003-7 Ferreira, A Ananias, D Carlos, LD Morais, CM Rocha, J Novel microporous lanthanide silicates with tobermorite-like structure JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125, 2003, 14573-14579. The synthesis and structural characterization of microporous lanthanide silicates (Na(1.08)K(0.5)Ln(1.14-)Si(3)O(8.5).1.78H(2)O, Ln = Eu, Tb, Sm, Ce) are reported. The structure of these solids is closely related with the structure of hydrated calcium silicate minerals known as tobermorites and was solved by powder X-ray diffraction ab initio (direct) methods and further characterized by chemical analysis, thermogravimetry, scanning electron microscopy, Na-23 and Si-29 MAS NMR and luminescence spectroscopy. These materials combine microporosity with interesting photoluminescence properties, and their structural flexibility allows fine-tuning of luminescence properties, by introducing a second type of lanthanide ion in the framework. Thus, they may find applications in new types of sensors. TREOR, DICVOL, 2003-8 Zavalij, PY Yang, SF Whittingham, MS Structures of potassium, sodium and lithium bis(oxalato)borate salts from powder diffraction data ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 59, 2003, 753-759. The crystal structures of the alkali-metal bis(oxalato) borate salts A[B(C2O4)(2)] (A = K, Na, Li) have been determined ab initio using powder diffraction data obtained from a laboratory diffractometer. The K compound crystallizes in the orthorhombic space group Cmcm and its structure has been solved by direct methods applied to the integrated intensities from full pattern decomposition. The Na compound is isostructural with the K salt, while the crystal structure of the highly hydroscopic Li compound differs from the other two. It has an orthorhombic lattice, space group Pnma, and its structure was solved by the global optimization method using a parallel tempering approach. In the K and Na structures the metal ions and complex borate ions form chains with m2m symmetry. Metal - oxygen bonding between the chains links them into a layer and then a framework with square tunnels. The coordination number of both K and Na is eight. The Li compound also contains chains that have. m. symmetry and are bound together into a three-dimensional framework. The coordination polyhedron of the Li atom is a square pyramid with Li lying in its base. This square pyramidal coordination leads to its high reactivity with moisture to give Li[B(C2O4)(2)] H2O with lithium in six coordination. TREOR 2003-9 Chernyshev, VV Machon, D Fitch, AN Zaitsev, SA Yatsenko, AV Shmakov, AN Weber, HP Protonation site and hydrogen bonding in anhydrous and hydrated crystalline forms of doxazosin mesylate from powder data ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 59, 2003, 787-793. The three-dimensional solid-state structures of two modifications of doxazosin mesylate C23H26N5O5+.CH3SO3-, 4-amino-2-[ 4-[(2,3-dihydro-1,4-benzodioxin-2-yl) carbonyl] piperazin-1-yl]- 6,7-dimethoxyquinazoline methanesulfonate, a commonly used antihypertensive agent, have been determined by synchrotron X-ray powder diffraction. An anhydrous form (A) and a dihydrate form (dG) crystallize in monoclinic space groups. In both forms the doxazosin molecule is protonated at the N1 atom of the quinazoline bicycle. The N1 atom, and the amino H atoms and O atoms of the mesylate moieties are involved in three-dimensional hydrogen-bonding networks, while solvent water molecules and carboxamide O atoms are also incorporated in a hydrogen-bonding network in dG. TREOR 2003-10 Miura, H Ushio, T Nagai, K Fujimoto, D Lepp, Z Takahashi, H Tamura, R Crystallization of a desired metastable polymorph by pseudoseeding, crystal structure solution from its powder X-ray diffraction data, and confirmation of polymorphic transition CRYSTAL GROWTH & DESIGN 3, 2003, 959-965. Described are the successful, selective crystallization and characterization of one (delta-form) of the metastable polymorphs of (+/-)-[2-[4-(3-ethoxy-2-hydroxypropoxy)phenylcarbamoyl]ethyl]dimethylsul fonium p-toluenesulfonate (1a), which is assumed to exist as a transient key-intermediate crystalline phase relevant to the mechanism of Preferential Enrichment, an unusual enantiomeric resolution phenomenon observed upon crystallization of a certain kind of racemates from solvents. By pseudoseeding the supersaturated solution with the delta-form seed crystals of an anlogous compound, the desired delta-form crystals of (+/-)-1a could be obtained as a monophasic powder sample. This selective crystallization can be interpreted in terms of the interplay between an inhibition of the nucleation or crystal growth process of the undesired stable alpha-polymorphic form and a heterogeneous nucleation of the desired metastable delta-form through epitaxy. The physicochemical properties of the delta-form. crystal such as melting point and solubility have been compared with those of the stable alpha-form one to evaluate the relative stability of the metastable delta-form. It has also been confirmed that polymorphic transition of the metastable delta-form crystal to the stable alpha-form one occurs in contact with a solvent. On the basis of the delta-form crystal structure solved from its powder X-ray diffraction data measured with a laboratory X-ray source by means of the direct-space approach employing the Monte Carlo method and the subsequent Rietveld refinement, the origin of the metastability of the delta-form crystal has been discussed. 2003-11 Fujimoto, D Tamura, R Lepp, Z Takahashi, H Ushio, T Mechanism of a new type of solvent-assisted solid-to-solid polymorphic transition causing preferential enrichment: Prominent influence of C(sp(2))H ...O interaction on the control of a crystal structure CRYSTAL GROWTH & DESIGN 3, 2003, 973-979. A new mode of the solvent-assisted solid-to-solid transformation of the first-formed and least stable gamma-polymorphic form into the most stable epsilon-polymorphic one occurring during crystallization from the supersaturated EtOH solution of (+/-)-[2-[4-(3-ethoxy-2-hydroxypropoxy)phenylcarbamoyl]ethyl]trimethylam monium benzenesulfonate [(+/-)-2], which shows an unusual enantiomeric resolution phenomenon called Preferential Enrichment, has been revealed. The crystal structure of the new epsilon-form, which was obtained as the monophasic powder sample by exhaustive polymorphic transitions via three other metastable polymorphic forms in contact with the solvent, has been solved from the powder X-ray diffraction data by the direct-space approach employing the Monte Carlo method with the subsequent Rietveld refinement. By comparison of the crystal structure of the least stable gamma-form with that of the most stable epsilon-one, the mechanism of this polymorphic transition has been interpreted in terms of a new type of rearrangement of weak intermolecular interactions caused by a slight molecular movement inside the crystal lattice, in which intermolecular C(sp(2))H...O interactions prominently control the crystal structure. This new finding complements our recent report on the mechamisn of Preferential Enrichment. TREOR 2003-12 Montejo-Bernardo, JM Garcia-Granda, S Bayod-Jasanada, MS Llavona-Diaz, L Llorente, I X-ray study of the pseudopolymorphism of the azithromycin monohydrate ZEITSCHRIFT FUR KRISTALLOGRAPHIE 218, 2003, 703-707. A combination of X-ray powder diffraction and single crystal studies on azithomycin pseudopolymorphs give the precise solid state composition of all monohydrate pseudopolymorphs reported. According to the X-ray results the four monohydrates of azithromycin studied have the same crystallographic parameters. Furthermore, the analysis of the relative intensities from the powder patterns points to very similar chemical compositions and crystal structures. This result has been confirmed by the single crystal studies. The single crystal studies show that the solid state conformation of the azithromycin molecules is affected by the presence of solvents. The solvent methanol molecules were found disordered probably due to the existence of many positions where the hydrogen bonding is favoured and the large size of the available space to host the solvents. TREOR 2003-13 Cheung, EY Harris, KDM Johnston, RL Hadden, KL Zakrzewsk, M Polymorphism of a novel sodium ion channel blocker JOURNAL OF PHARMACEUTICAL SCIENCES 92, 2003, 2017-2026. 2-{[4-(4-Fluorophenoxy)phenyl]-methylene}-hydrazinecarboxamide,a member of the semicarbazone family which has shown potential therapeutic use as anticonvulsants, has been found to exist in two polymorphic forms denoted A and B. In addition to reporting aspects of the physical characterization of both forms, the crystal structure of polymorph A has been determined directly from powder X-ray diffraction data using the Genetic Algorithm technique for structure solution, followed by Rietveld refinement. This structure is compared with that of polymorph B, which was determined previously from single crystal X-ray diffraction data. Knowledge of the crystal structures of the two polymorphs provides the opportunity for establishing structure-property relationships. This work further emphasizes the scope and utility of ab initio structure solution from powder X-ray diffraction data in the pharmaceuticals field. TREOR 2003-14 - failed... ?? Masciocchi, N Castelli, F Forster, PM Tafoya, MM Cheetham, AK Synthesis and characterization of two polymorphic crystalline phases and an amorphous powder of nickel(II) bisimidazolate INORGANIC CHEMISTRY 42, 2003, 6147-6152. Nickel(II) bisimidazolate is polymorphic. Depending on the synthetic strategy adopted, two crystalline phases (alpha- and beta-Ni(im)(2)) or an amorphous material of the same composition can be prepared. The thermodynamically stable alpha-Ni(im)(2) phase, which can be prepared in water at elevated temperatures, contains a two-dimensional polymer (of nearly square meshes) with square-planar NiN4 chromophores and exo-bidentate imidazolate ligands bridging nickel atoms that are ca. 5.73 Angstrom apart. The beta-Ni(im)(2) Phase can be kinetically stabilized at lower temperatures, but the structural complexity and the lack of single crystals prevented its full structural characterization, even in the presence of an indexed powder diffraction pattern. The spectroscopic features of these crystalline phases are compared with those of the amorphous material. TREOR 2003-15 Le Bail, A Stephens, PW Hubert, F A crystal structure for the souzalite/gormanite series from synchrotron powder diffraction data EUROPEAN JOURNAL OF MINERALOGY 15, 2003, 719-723. In absence of suitable single crystal due to polysynthetic twinning, the crystal structure of a specimen in the souzalite/gormanite series (Fe,Mg)(3)(Al,Fe)(4)(PO4)(4)(OH)(6).2H(2)O is determined ab initio from synchrotron powder diffraction data. The crystals belong to space group P (1) over bar, the cell is different from previously reported with a=7.2223(1), b=11.7801(1), c=5.1169(1) Angstrom; alpha=90.158(1), beta=109.938(1), gamma=81.330(1)degrees; V=404.02(1) Angstrom(3); Z=1. The structure consists of infinite chains of alternating [FeO6], [MgO6] and [AlO6] octahedra sharing faces and/or edges. These chains are connected by corners with clusters of three corner-sharing [AlO6] octahedra, forming octahedral layers which are interconnected by [PO4] groups. A comparison with other minerals of similar composition and structure is made (dufrenite, burangaite). TREOR, DICVOL 2003-16 Tafeenko, VA Chernyshev, VV Yatsenko, AV Makarov, VA Sonneveld, EJ Peschar, R Schenk, H Intermolecular -CH3 . . . O2N-contacts in two polymorphic modifications of (1E)-N '-[(E)-2-cyano-1-(dimethylamino)-2-nitrovinyl]-N,N-dimethylethanimidamide ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 59, 2003, 492-497. The title compound was synthesized and isolated in two crystal modifications. The structure of the orthorhombic modification was determined by the X-ray powder diffraction method and the structure of the monoclinic modification was determined using the X-ray single-crystal diffraction technique. The molecules in both polymorphs are E, E isomers. Intermolecular H3C...NO2 contacts and their role in the formation of the polymorphic modifications are analyzed. TREOR 2003-17 Masciocchi, N Ardizzoia, GA Brenna, S Castelli, F Galli, S Maspero, A Sironi, A Synthesis and ab-initio XRPD structure of group 12 imidazolato polymers CHEMICAL COMMUNICATIONS iss 10, 2003, 2018-2019. Two new 3D homoleptic binary imidazolates, Cd(im)(2) and Hg(im)(2) (Him = imidazole), as well as [Hg(im)]NO3, containing 1D polycations of [Hg(im)](n)(n+) formulation, have been prepared and characterized by ab-initio XRPD methods. TREOR 2003-18 Ivashkevich, LS Lyakhov, AS Selevich, AF Petrusevich, YI The crystal structure of Er(HPO4)(NO3) . 3 H2O: ab initio determination from X-ray powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE 218, 2003, 475-479. The crystal structure of orthorhombic Er(HPO4)(NO3) . 3 H2O has been determined from X-ray powder diffraction data. The unit cell dimensions are a = 10.1653(4) Angstrom, b = 11.9178(5) Angstrom, c = 6.8533(3) Angstrom, V = 830.26(6), Z = 4. The space group is Pbcm (No. 57) or Pbc2(1) (No. 29). The structures were solved ab initio using EXPO program and refined by FULLPROF package. Because geometrical features of the two solutions are the same, the crystal structure has been described in the scope of the centrosymmetric Pbcm space group. Positions of the hydrogen atoms were not defined. The erbium atom is eight coordinated. It is surrounded by one nitrate anion, one water molecule and four phosphate groups. [ErO8] polyhedra are linked together through their edges forming infinite chains extended along the c axis. The chains are connected by phosphate groups to form layers palallel to the yz plane. Probable hydrogen bonds are discussed. TREOR 2003-19 Nowell, H Shan, N Attfield, JP Jones, W Motherwell, WDS The structure of cyclohexane-1, 3cis, 5cis-tricarboxylic acid, determined from powder X-ray diffraction data CRYSTAL ENGINEERING 6, 2003, 57-67. The previously unknown crystal structure of cyclohexane-1, 3cis, 5cis-tricarboxylic acid (CTA) has been solved from laboratory X-ray powder diffraction data using a simulated annealing algorithm followed by restrained Rietveld refinement (reduced-chi(2) = 8.531 for the refined crystal structure). The structure is triclinic (P (1) over bar, Z = 4). Five out of six of the CO2H groups in the asymmetric unit form R-2(2)(8) hydrogen bond motifs with neighbouring CO2H groups. The motifs connect molecules to form pseudo-hexagonal, ten-molecule rings that fuse into supramolecular buckled honeycomb sheets, which stack and are linked by O-(HO)-O-... hydrogen bonds. TREOR 2003-20 Masciocchi, N Brenna, S Galli, S Maspero, A Ab-initio XRPD structural characterization of coordination polymers: the case of [Ag(C3H3N2CS2)] ZEITSCHRIFT FUR KRISTALLOGRAPHIE 218, 2003, 450-454. The crystal structure of the one-dimensional polymer [Ag(C3H3N2CS2)] has been determined from conventional X-ray powder diffraction methods, through simulated annealing and Rietveld refinement techniques [Ag(C3H3N2CS2)] is monoclinic, P2(1)/c; a = 8.409(l), b = 11.740(l), c = 6.721(l) Angstrom, beta = 101.86(2)degrees, V = 649.3(2) Angstrom(3); Z = 4; rho = 2.566 g cm(-3) Final R-wp, R-p and R-F agreement factors, for 3 100 data points collected in the 8-70degrees 2theta range, are 0.091, 0.071 and 0.058, respectively. Anisotropic peak shapes and high-angle tails for the 0k0 (and neighboring) reflections suggest that the polymeric chains, aligned along b, suffer from a partial disorder, in that packing of adjacent molecules does not conform to a rigorous crystalline, truly periodic, tiling. TREOR 2003-21 Ivashevskaja, SN Aleshina, LA Andreev, VP Nizhnik, YP Chernyshev, VV Schenk, H 4-(4 '-dimethylaminostyryl)pyridine N-oxide from powder data ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 59, 2003, O1006-O1008 The crystal structure of 4-(4-dimethylaminophenylethenyl)pyridine N-oxide, C15H16N2O, has been determined from X-ray laboratory powder diffraction data. The powder pattern was indexed with a monoclinic unit cell with a long a axis. The structure was solved by a grid search technique. The subsequent bond-restrained Rietveld refinement gave bond lengths and angles within expected ranges. TREOR 2003-22 Grzechnik, A Bouvier, P Farina, L High-pressure structure of Li2CO3 JOURNAL OF SOLID STATE CHEMISTRY 173, 2003, 13-19. The high-pressure behavior of Li2CO3 is studied up to 25 GPa with synchrotron angle-dispersive powder X-ray diffraction in diamond anvil cells and synthesis using a multi-anvil apparatus. A new non-quenchable hexagonal polymorph (P6(3)/mcm, Z = 2) occurs above 10 GPa with carbonate groups in a staggered configuration along the c-axis-a = 4.4568(2) Angstrom and c = 5.1254(6) Angstrom at 10 GPa. Two columns of face-shared distorted octahedra around the Li atoms are linked through octahedral edges. The oxygen atoms are coordinated to one carbon atom and four lithium atoms to form a distorted square pyramid. Splittings of X-ray reflections for the new polymorph observed above about 22 GPa under non-hydrostatic conditions arise from orthorhombic or monoclinic distortions of the hexagonal lattice. The results of this study are discussed in relation to the structural features found in other Me2CO3 carbonates (Me: Na, K, Rb, Cs) at atmospheric conditions. TREOR 2003-23 Le Bail, A Mercier, AM Distorted chiolite crystal structures of alpha-Na5M3F14 (M=Cr,Fe,Ga) studied by X-ray powder diffraction POWDER DIFFRACTION 18, 2003, 128-134. The crystal structures of the chiolite-related room temperature phases alpha-Na5M3F14 (M-III =Cr,Fe,Ga) are determined. For all of them, the space group is P2(1)/n, Z=2; a= 10.5096(3) Angstrom, b=7.2253(2) Angstrom, c=7.2713(2) Angstrom, beta=90.6753(7)degrees (M = Cr); a= 10.4342(7) Angstrom, b = 7.3418(6) Angstrom, c = 7.4023(6) Angstrom, beta=90.799(5)degrees (M = Fe), and a= 10.4052(1) Angstrom, b=7.2251(1) Angstrom, c=7.2689(1) Angstrom, beta=90.6640(4)degrees (M = Ga). Rietveld refinements produce final R-F factors 0.036, 0.033, and 0.035, and R-WP factors, 0.125, 0.116, and 0.096, for M-III=Cr, Fe, and Ga, respectively. The MF6 polyhedra in the defective isolated perovskite-like layers deviate very few from perfect octahedra. Subtle octahedra tiltings lead to the symmetry decrease from the P-4/mnc space group adopted by the Na5Al3F14 chiolite aristotype to the P2(1) In space group adopted by the title series. Facile twinning precluded till now the precise characterization of these compounds. 2003-24 Crichton, WA Mezouar, M Monaco, G Falconi, S Phosphorus: New in situ powder data from large-volume apparatus POWDER DIFFRACTION 18, 2003, 155-158. Improved X-ray powder diffraction data for orthorhombic phosphorus, S.G. Cmca (64) obtained in situ at synthesis conditions of 1.2 GPa and 1100 K, are described. Representative, as synthesized, data include 2.552(X), 3.320(4), 2.595(3), 5.191(2), 1.630(2), for least-squares unit-cell a=3.3182(6) Angstrom, b= 10.3744(18) Angstrom and c=4.3227(9) Angstrom. As an illustration of the quality of the data, the structure was solved from powder XRD and Rietveld refined to give a=3.3199(2) Angstrom, b= 10.3678(4) Angstrom, c=4.3154(2)Angstrom, and V=148.535(12) Angstrom(3) with the P atom on 8f (1/2, y,z) with y=0.1044(22) and z=0.9179(7). (C) 2003 International Centre for Diffraction Data. 2003-25 Grzechnik, A Crichton, WA Gesland, JY Potassium triyttrium decafluoride, KY3F10, synthesized at high pressures and high temperatures SOLID STATE SCIENCES 5, 2003, 757-764. Potassium triyttrium decafluoride, KY3F10, has been studied at high pressures and high temperatures using in situ synchrotron angle-dispersive X-ray powder diffraction in a Paris-Edinburgh cell and syntheses in a multi-anvil apparatus. At ambient conditions this compound exhibits a 2 x 2 x 2-fluorite superstructure (Fm (3) over barm, Z = 8, a = 11.54315(1) Angstrom) with yttrium atoms displaced from the ideal fcc positions. Upon compression to above 7.5 GPa at room temperature, a new polymorph is formed (Pm (3) over barn, Z = 1, a = 5.70485(8) Angstrom for the sample synthesized at 10.5 GPa and 298 K) with potassium and yttrium atoms in the ideal fluorite positions. Fluorine atoms are disordered and split on partially occupied sites. The same phase of KY3F10 is obtained at lower pressures and high temperatures. This new structure is discussed in relation to other fluorite superstructures. TREOR 2003-26 Masciocchi, N Galli, S Sironi, A Barea, E Navarro, JAR Salas, JM Tabares, LC Rich structural and magnetic chemistry of cobalt(II) pyrimidin-2-olate and pyrimidin-4-olate complexes. Synthesis, X-ray powder diffraction studies, and thermal behavior CHEMISTRY OF MATERIALS 15, 2003, 2153-2160. Two new cobalt(II) species containing the pyrimidin-4-olate ligand (4-pymo) have been prepared and fully characterized by spectroscopic, thermal, and ab initio X-ray powder diffraction methods. The magnetic properties of both these species and Co(2-pymo)(2), an extended cobalt(II) compound containing the pyrimidine-2-olate ligand (2-pymo), are also reported. Co(4-pymo)(2)(H2O)(4) (1) [orthorhombic, Pcab, a = 13.5233(4) Angstrom, b = 12.9617(3) Angstrom, and c = 6.7925(2) Angstrom] consists of D-4h octahedral monomers, bearing axial 4-pymo ligands, interlinked by an extensive network of OH...X (X = O, N) hydrogen bonds. Upon heating, it loses water and transforms into an amorphous (above 150 degreesC) (2a) or a polycrystalline above 320 degreesC) Co(4-pymo)(2) phase (2b) [orthorhombic, Imma, a = 6.5720(8) Angstrom, b = 6.6209(8) Angstrom, and c = 20.688(2) Angstrom]. In the latter, C-2v pseudo-tetrahedral cobalt(II) ions are linked by 4-pymo ligands in the unusual N,O-exo-bidentate mode, generating 2D layers of nearly square meshes, thus significantly differing from the Co(2-pymo)(2) analogue (3), in which N,N'-exo-bidentate bridges generate an acentric, 3D diamondoid network. The thermal dependence of the magnetic susceptibility has been studied for all the above compounds (1, 2a, 2b, and 3) in the 2-300 K temperature range. The magnetic behavior of 1 is dominated by spin-orbit coupling of magnetically isolated octahedral Co(II) centers. The extended materials 2a and 2b show antiferromagnetic exchange between distorted tetrahedral metal centers, whereas 3 behaves as a spin-canted antiferromagnet, a ferromagnetic ordering taking place below a critical temperature, T-c = 23 K; 3 can thus be considered as a molecular magnet. Indeed, magnetic hysteresis studies on 3 at 4.8 K yield a coercitive field H-coer = 3900 G and a remnant magnetization M-rem = 279 cm(3) G mol(-1). TREOR 2003-27 Cecconi, F Dominguez, S Masciocchi, N Midollini, S Sironi, A Vacca, A Complexation of beryllium(II) ion by phosphinate ligands in aqueous solution. Synthesis and XRPD structure determination of Be[(PhPO2)(2)CH2](H2O)(2) INORGANIC CHEMISTRY 42, 2003, 2350-2356. Two bifunctional ligands, phenyl(carboxymethyl)phosphinate (ccp(2-)) and P,P'-diphenylmethylenediphosphinate (pcp(2-)), have been tested as chelating agents of beryllium(II). Both ligands have the same charge and a similar chelating structure, but whereas the 1:1 adduct of pcp(2-), Be(pcp)((HO)-O-2)(2), could be isolated as a white powder, no pure compound could be isolated from solutions containing beryllium(II) and ccp(2-). Instead, the solutions were examined by means of potentiometry and Be-9 NMR spectroscopy. Analysis of the potentiometric titration data with the program HYPERQUAD suggested the formation of the complex species BeL, [BeHL](+), [BeL2](2-), and [BeHL2](-) (L = ccp). The formation constants for these species were determined at 25 degreesC and / = 0.5 mol dm(-3) NaCIO4. The Be-9 NIVIR spectra are consistent with this model. The formation constants found for the ccp(2-) complexes are lower than those reported for related phosphonate ligands. However, the effective stability constant (which gives a better indication of the intrinsic coordinating capacity of the ligand at a particular pH) of the complex [Be(ccp)(2)](2-) at pH < 4 is greater than the effective constants of the corresponding phosphonoacetate and methylenediphosphonate complexes. The structure of Be(pcp)(H2O)(2) was determined by X-ray powder diffraction methods and consists of discrete molecules interconnected by an extended 2D network of hydrogen bonds, resulting in a stacking of double layers with a polar core and a lipophilic surface. Crystal data: C13H16BeO6P2, fw 339.21, monoclinic P2(1)/c, a 16.174(1) Angstrom, b = 8.979(1) Angstrom, c = 10.929(1) Angstrom, beta = 90.398(9)degrees, V = 1587.2(3) Angstrom(3), Z = 4. TREOR 2003-28 Boullay, P Mercurio, D Bencan, A Meden, A Drazic, G Kosec, M An XRPD ab-initio structural determination of La2RuO5 JOURNAL OF SOLID STATE CHEMISTRY 170, 2003, 294-302. The crystal structure of a new oxide, La2RuO5, was determined ab initio using conventional laboratory X-ray powder diffraction. Combining X-ray and electron diffraction techniques, we found that the new phase crystallized in the monoclinic system with the space group P2(1)/c (SG no.14) and the cell parameters a 9.1878(2) Angstrom, b=5.8313(2) Angstrom, c 7.9575(2) Angstrom and beta=100.773(2)degrees (V=418.8 Angstrom(3), Z=4). The structural determination with the Patterson method and Fourier difference syntheses and the final Rietveld refinement were performed by means of the JANA2000 program. The structure is built up from the regular stacking, of a two octahedra thick [LaRuO4](infinity) zigzag perovskite slab and an original similar to3.4 Angstrom thick [LaO](infinity) slab which constitutes the key feature of this new structure. (C) 2002 Elsevier Science (USA). All rights reserved. TREOR 2003-29 Juarez-Arellano, EA Bucio, L Hernandez, JA Camarillo, E Carbonio, RE Orozco, E Synthesis, crystal structure, and preliminary study of luminescent properties of InTbGe2O7 JOURNAL OF SOLID STATE CHEMISTRY 170, 2003, 418-423. A new indium terbium germanate InTbGe2O7, which is a member of the thortveitite family, was prepared as a polycrystalline powder material by high-temperature solid-state reaction. This new compound crystallizes in the monoclinic system, space group C2/c (No. 15), with unit cell parameters a = 6.8818(2)Angstrom, b = 8.8774(3)Angstrom, c = 9.7892(4)Angstrom, beta = 101.401 (1)degrees V = 586.25(4)Angstrom(3) and Z = 4. Its structure was characterized by Rietveld refinement of powder laboratory X-ray diffraction data. It consists of octahedral sheets that are held together by sheets of isolated Ge2O7 diorthogroups composed of two tetrahedra sharing a common vertex. It contains only one octahedral site occupied by In3+ and Tb+3 cations. The characteristic mirror plane in the thortveitite (SC2Si2O7) space group (C2/m, No. 12) is not present in this new compound. Besides, in InTbGe2O7, the Ge-O-Ge angle bridging two diorthogroups is 156.8(2)degrees as compared to the one in thortveitite, which is 180degrees. On the other hand, luminescent properties were observed when it is excited with 376.5 nm wavelength. The luminescence spectrum shows typical transitions from the D-5(4) multiplet belonging to the trivalent terbium ion. TREOR 2003-30 Hassfjell, S Kongshaug, KO Romming, C Synthesis, crystal structure and chemical stability of bismuth(III) complexed with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid (H8DOTMP) DALTON TRANSACTIONS 2003, 1433-1437. The potential use of the alpha-particle emitting compounds Bi-212/213 -DOTMP and Pb-212-DOTMP in therapy of bone-associated cancers, and medical interest in bismuth compounds, motivated this study. Syntheses of the Bi(III) and Pb(III) complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid (H8DOTMP) are reported. Extensive pH-stability was found for both complexes, in the pH range 0-13 for Bi-DOTMP and pH 4-14 for Pb-DOTMP. Furthermore, both complexes formed within 1 min in the pH range 6-10 at 10 muM metal-ion and 15 muM DOTMP. Single crystals of [NaBi(H4DOTMP)] and polycrystalline [Bi(H5O2)(H4DOTMP)] were formed and characterized by single crystal and powder X-ray diffraction methods, respectively. The structure of the anion was found in both salts to exhibit a square antiprismatic eight-coordination with a four-fold axis of symmetry. TREOR 2003-31 Bellitto, C Bauer, EM Ibrahim, SA Mahmoud, MR Righini, G Synthesis, X-ray powder structure, and magnetic properties of layered Ni-II methylphosphonate, [Ni(CH3PO3)(H2O)], and Ni-II octadecylphosphonate, [Ni{CH3-(CH2)(17)-PO3}(H2O)] CHEMISTRY-A EUROPEAN JOURNAL 9, 2003, 1324-1331. [Ni(CH3PO3)(H2O)] (1) and [Ni[CH3-(CH2)(17)-PO3}(H2O)] (2) were synthesised by reaction of NiCl2 . 6H(2)O and the relevant phosphonic acid in water in presence of urea. The compounds were characterised by elemental and thermogravimetric analyses, UV-visible and IR spectroscopy, and their magnetic properties were studied by using a SQUID magnetometer. The crystal structure of I was determined ''ab initio" from X-ray powder diffraction data and refined by the Rietveld method. The crystals of 1 are orthorhombic, space group Pmn2(1), with a = 5.587(1), b = 8.698(1), c = 4.731(1) Angstrom. The compound has a hybrid, layered structure made up of alternating inorganic and organic layers along the b direction of the unit-cell. The inorganic layers consist of Ni-II ions octahedrally coordinated by five phosphonate oxygen atoms and one oxygen atom from the water molecule. These layers are separated by bilayers of methyl groups and van der Waals contacts are established between them. A preliminary structure characterisation of compound 2 suggests the crystallisation in the orthorhombic system with the following unit-cell parameters: a = 5.478(7), b = 42.31(4), c = 4.725(3) Angstrom. The oxidation state of the Ni ion in both compounds is +2, and the electronic configuration is d(8) (S = 1), as determined from static magnetic susceptibility measurements above 50 K. Compound 1 obeys the Curie-Weiss law at temperatures above 50 K; the Curie (C) and Weiss (0) constants were found to be 1.15 cm(3) K mol(-1) and -32 K, respectively. The negative value of theta indicates an antiferromagnetic exchange coupling between near-neighbouring Ni-II ions. No sign of 3D antiferromagnetic long-range order is observed down to T = 5 K, the lowest measured temperature. Compound 2 is paramagnetic above T= 50 K, and the values of C and 0 were found to be 1.25 cm(3) K mol(-1) and - 24 K, respectively. Below 50 K the magnetic behavior of 2 is different from that of 1. Zero-field cooled (zfc) and field-cooled (fc) magnetisation plots do not overlap below T= 21 K. The irreversible magnetisation, DeltaM(fc-zfc), obtained as a difference from fc and zfc plots starts to increase at T= 20 K, on lowering the temperature, and it becomes steady at T= K. The presence of spontaneous magnetisation below T = 20 K indicates a transition to a weak-ferromagnetic state for compound 2. TREOR, N-TREOR 2003-32 Yamada, H Shi, WS Nishikubo, K Xu, CN Determination of the crystal structure of spherical particles of SrAl2O4 : Eu prepared by the spray method JOURNAL OF THE ELECTROCHEMICAL SOCIETY 150, 2003, E251-E254. The crystal structure of spherical particles of Sr0.88Eu0.12Al2O4 synthesized by the spray method has been investigated by powder X-ray diffraction measurements. After annealing at 1300degreesC for 2 h, the spheres of Sr0.88Eu0.12Al2O4 crystallize in the hexagonal form with a = 5.1160(2) Angstrom, c = 8.3722(3) Angstrom, V = 189.77(1) Angstrom(3), Z = 2, and space group P6(3)22, which is distinct from the structure (monoclinic P2(1)) reported so far. This stable crystal structure was refined by the Rietveld method, and it was found that it consists of a nondistorted stuffed tridymite structure, and the doped Eu2+ ion is located at the same 2b site as the Sr2+ ion. Furthermore, it is suggested that such an abnormal stabilization of the hexagonal form at ambient temperature is associated with defects of the oxygen ion at the 2d site based on the electron density map from Fourier synthesis. TREOR 2003-33 Ivashkevich, LS Lyakhov, AS Selevich, AF Lesnikovich, AI Ab initio structure determination of In2H2(P2O7)(P4O12))(P4O12) from X-ray powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE 218, 2003, 32-36. The crystal structure of In2H2(P2O7)P4O12) has been determined from X-ray powder diffraction data. The structure is orthorhombic, space group Pmmn (No. 59), with unit cell dimensions a = 12.9398(2) Angstrom, b = 11.3725(3) Angstrom, c = 5.0385(1) Angstrom, V = 741.45(3) Angstrom, Z = 2, and D-x = 3.23 g/cm(3). The structure has been solved by direct methods using EXPO program and refined by FULLPROF package. The final R-Bragg value was 4.6%. Positions of hydrogen atoms were not defined. Indium cation has sixfold oxygen coordination being surrounded by two diphosphate and four cyclotetraphosphate groups. Probable scheme of hydrogen bonding is discussed. TREOR 2003-34 Simon-Masseron, A Paillaud, JL Patarin, J Mu-21: A three-dimensional microporous zincophosphate obtained by direct synthesis and reversible dehydration of the zincophosphate Mu-19 CHEMISTRY OF MATERIALS 15, 2003, 1000-1005. A zincophosphate named Mu-21 (Zn4P8O32H12(C5H12NO)(4)) was obtained in solvothermal conditions from a ZnO/H3PO4/N-methylmorpholine/ethylene glycol mixture, and its structure was solved ab initio from powder data. Mu-21 crystallized in the orthorhombic space group P 2(1)2(1)2(1) with a = 10.4200(1), b = 10.4523(2), c = 11.6221(2) Angstrom, and V = 1265.80(3) Angstrom(3). Mu-21 was also obtained by reversible dehydration of the zincophosphate Mu-19 at 80 degreesC. This material was characterized by P-31, H-1 MAS NMR, and SEM. TREOR 2003-35 Kiang, YH Xu, W Kaufman, MJ Ab initio structure determination of rofecoxib from powder diffraction data using molecular packing analysis method and direct space method INTERNATIONAL JOURNAL OF PHARMACEUTICS 252, 2003, 213-223. Crystal structures of a COX-II inhibitor, rofecoxib (Vioxx(R)) were solved ab initio from X-ray powder diffraction pattern using both molecular packing analysis and direct space methods. The X-ray powder pattern was indexed into a tetragonal cell. Packing energies were generated and analyzed in eight most frequently found tetragonal space groups. The two space groups with the lowest total energy, P4(1)2(1)2 and P4(3)2(1)2, were used for direct space method with a Monte-Carlo/Simulated Annealing searching algorithm. Structural solutions obtained from direct space method were evaluated using molecular packing energy analysis. The structures solved ab initio from this work were compared to the single crystal structure deposited in the Cambridge Structural Database. TREOR 2003-36 Burton, A Elomari, S Medrud, RC Chan, IY Chen, CY Bull, LM Vittoratos, ES The synthesis, characterization, and structure solution of SSZ-58: A novel two-dimensional 10-ring pore zeolite with previously unseen double 5-ring subunits JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125, 2003, 1633-1642. The synthesis, structure solution, and characterization of the novel zeolite SSZ-58 are described. SSZ-58 was synthesized under hydrothermal conditions using 1-butyl-1-cyclooctylpyrrolidinium cation as a structure-directing agent. The framework topology of SSZ-58 was determined with the FOCUS Fourier recycling method. SSZ-58 possesses 12 tetrahedral atoms in the asymmetric unit of its highest topological symmetry, and to date it is the most complex zeolite structure solved from powder data. Rietveld refinement of synchrotron powder X-ray diffraction data in space group Pmma confirmed the proposed model. SSZ-58 contains layers of atoms that are linked together by double five-membered rings (D5R), or 5(2)4(5) subunits, that have not been observed before in any zeolite or zeotype structures. SSZ-58 possesses a two-dimensional channel system consisting of 10-membered ring pores that intersect to form large Cavities circumscribed by 12- and 16-membered ring pores. TREOR, DICVOL 2003-37 Huq, A Stephens, PW Subtleties in crystal structure solution from powder diffraction data using simulated annealing: Ranitidine hydrochloride JOURNAL OF PHARMACEUTICAL SCIENCES 92, 2003, 244-249. Recent advances in crystallographic computing and availability of high-resolution diffraction data have made it relatively easy to solve crystal structures from powders that would have traditionally required single crystal samples. The success of direct space methods depends heavily on starting with an accurate molecular model. In this paper we address the applicability of using these methods in finding subtleties such as disorder in the molecular conformation that might not be known a priori. We use ranitidine HCl as our test sample as it is known to have a conformational disorder from single crystal structural work. We redetermine the structure from powder data using simulated annealing and show that the conformational disorder is clearly revealed by this method (C) 2003 Wiley-Liss, Inc. TREOR 2003-38 Jorda, JL McCusker, LB Baerlocher, C Morais, CM Rocha, J Fernandez, C Borges, C Lourenco, JP Ribeiro, MF Gabelica, Z Structure analysis of the novel microporous aluminophosphate IST-1 using synchrotron powder diffraction data and HETCOR MAS NMR MICROPOROUS AND MESOPOROUS MATERIALS 65, 2003, 43-57. A combination of advanced powder diffraction and NMR techniques have allowed the structure of the novel microporous aluminophosphate IST-1 (\(CH3NH2)(4)(CH3NH3+)(4)(OH-)(4)\[Al12P12O48] to be elucidated. The framework structure was determined in the non-centrosymmetric space group Pca2(1) (a = 9.61523(1) Angstrom, b = 8.67024(1) Angstrom, c = 16.21957(2) Angstrom) from high-resolution synchrotron powder diffraction data using the program FOCUS. Extra framework species were then located on difference electron density maps. A hydroxyl group was found to bridge between two of the framework Al atoms, and one methylamine species, presumably protonated, could be located in the channels where it H-bonds to three framework oxygens. The most unusual feature of the structure is the second methylamine molecule, which bonds directly to a framework Al atom. The structure is entirely consistent with P-31 and Al-27 MAS NMR studies, which showed there to be three P (all 4-coordinate) and three At (one 4-, one 5- and one 6-coordinate) sites, and with C-13 MAS NMR, which showed there to be two different types of methylamine species in equal amounts. Assignment of the P-31, Al-27 and C-13 MAS NMR signals could be deduced from the crystallographic data, P-31-Al-27 HETCOR spectra and ab initio calculations. N-TREOR 2003-39 Blomqvist, H Ronnebro, E Kyoi, D Sakai, T Noreus, D Structural characterization of Mg3MnH similar to 6 - a new high-pressure phase synthesized in a multi-anvil cell at 6 GPa JOURNAL OF ALLOYS AND COMPOUNDS 358, 2003, 82-86. With modem X-ray diffraction refinement methods it was shown to be possible to identify a new Mg3MnH-6 phase from a minute sample volume in spite of poor crystallinity and coexisting impurity phases. The new hydride was synthesized at 6 GPa in a high-pressure multi-anvil cell at 873 K. A monoclinic unit cell was found with a=8.827(2), b=4.657(2), c=4.676(2) Angstrom and beta=105.74(2)degrees, space group P2(1)/m (no. 11), Z = 2, V = 184.99 Angstrom(3). Manganese is surrounded by a distorted cube of magnesium with average Mn-Mg distances of 2.78(2) Angstrom. The cubes share edges in the b and c directions of the unit cell but are separated by a distance of approximate to 3.6 Angstrom along a, forming a layered structure. The hydrogen positions were not possible to determine, as only a small sample amount could be prepared. If the metal atom structure of the title compound is compared to the already known Mg3MnH7 it can be concluded that Mg3MnH-6 also consists of manganese hydrido complexes counterbalanced by magnesium ions, but with a different alignment of the magnesium cubes. N-TREOR 2003-40 Couhorn, U Dronskowski, R Alkali-metal ortho-hydroxyphenolates: Syntheses and crystal structures from powder X-ray diffraction ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 629, 2004, 2554-2558. Colorless and highly air- and moisture-sensitive powders of M[o-C6H4O(OH)] with M = K, Rb, or Cs have been synthesized from reaction mixtures of the appropriate alkali metal and catechol in thf. All compounds were structurally characterized by means of powder X-ray diffraction using the Rietveld profile refinement technique including restraints for the C-C/C-O bond distances and the C-C-C angles. The atomic arrangements of M[o-C6H4O(OH)] (K: monoclinic P2(1)/c; Rb/Cs: orthorhombic Pbcm) are characterized by polymeric chains of (1)(infinity)[M(1)([4])O(2)([2])eta(6)] units connected by hydrogen bonds, thereby making up layered structures similar to the one of catechol. The coordinatively unsaturated alkali metals are forming edge-sharing MO4 pyramids and exhibit asymmetrical eta(6)-interactions with the phenylene rings. The symmetry of the unit cells increases with increasing size of the cation, and this results in a decrease of the monoclinic angle from 118.5degrees (catechol) to 93.7degrees (K compound), eventually leading to orthorhombic cells for the Rb and Cs compounds. DICVOL 2003-41 ??? Guillou, N Livage, C Drillon, M Ferey, G The chirality, porosity, and ferromagnetism of a 3D nickel glutarate with intersecting 20-membered ring channels ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 42, 2003, 5314-5317. 2003-42 Tedesco, E Della Sala, F Favaretto, L Barbarella, G Albesa-Jove, D Pisignano, D Gigli, G Cingolani, R Harris, KDM Solid-state supramolecular organization, established directly from powder diffraction data, and photoluminescence efficiency of rigid-core oligothiophene-S,S-dioxides JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125, 2003, 12277-12283. The "rigid-core" material 3,5-dimethyl-2,3'-bis(3-methylthiophene)-dithieno[3,2-b:',3'-d]thiophene -4,4-dioxide (DTTOMe4) has the highest photoluminescence ever reported for thiophene-based molecules in the solid state. We report the structure of this material, determined directly from powder X-ray diffraction data using the Genetic Algorithm method for structure solution, followed by Rietveld refinement, and the structural properties are discussed in relation to the structures of the corresponding subsystems DTTO and DTTOMe. While the crystal structures of the latter compounds contain cofacial dimers, the crystal structure of DTTOMe4 comprises layers of molecules aligned in an antiparallel fashion. Intermediate neglect of differential overlap with single configuration interaction (INDO/SCI) calculations on the intermolecular interactions in the three crystal structures show that the different solid-state photoluminescence efficiencies of DTTOMe4, DTTOMe, and DTTO cannot be correlated with the different types of dipole-dipole alignment in the solid state. Instead, photoluminescence efficiencies correlate well with the rate of formation of nonradiatively decaying charge-transfer pairs upon photoexcitation. Because of larger intermolecular distances in DTTOMe4, the photoluminescence is less effectively quenched by charge-transfer processes than in DTTOMe and DTTO. DICVOL 2003-43 Boudaren, C Auffredic, JP Louer, M Louer, D A powder X-ray diffraction study of lead chloride oxalate Pb2Cl2(C2O4): ab initio structure determination and thermal behavior POWDER DIFFRACTION 18, 2003, 205-213. Mixed lead chloride oxalate, Pb2Cl2(C2O4), has been obtained in a polycrystalline form in the course of a study on precursors of nanocrystalline PZT-type oxides. Its crystal structure has been solved ab initio from powder diffraction data collected using a monochromatic radiation from a conventional X-ray source. The symmetry is monoclinic, space group C2/m, the cell dimensions are a = 5.9411(3) Angstrom, b = 5.8714(4) Angstrom, c = 9.4212(4) Angstrom, beta = 95.232(4)degrees and Z = 2. The structure consists of a stacking of complex double sheets, built from lead polyhedra, parallel to (001) and connected together through oxalate groups. The lead atom is nine-fold coordinated by four 0 atoms from one bidentate and two monodentate oxalate groups and five Cl atoms. The polyhedron can be described as a highly distorted square antiprism mono-capped by a Cl atom. The thermal behavior of lead chloride oxalate, in vacuum and in air, is carefully described from temperature-dependent powder diffraction and thermogravimetric measurements. It is shown that reaction pathways are complicated by the identification of various oxide chloride phases. DICVOL 2003-44 ??? Barthelet, K Adil, K Millange, F Serre, C Riou, D Ferey, G Synthesis, structure determination and magnetic behaviour of the first porous hybrid oxyfluorinated vanado(III)carboxylate: MIL-71 or V-2(III)(OH)(2)F-2{O2C-C6H4-CO2}center dot H2O JOURNAL OF MATERIALS CHEMISTRY 13, 2003, 2208-2212. A new type of three-dimensional vanadium(III) dicarboxylate, MIL-71 or V-2(III)(OH)(2)F-2{O2C-C6H4-CO2}.H2O, has been obtained under hydrothermal conditions from aqueous mixtures of vanadium, 1,4-benzenedicarboxylic acid, and HF. MIL-71cal or (V2O2F2)-O-IV{O2C-C6H4-CO2} is obtained by calcination of the parent compound in air at 250 degreesC. The three-dimensional structure of MIL-71 (S.G.: Cmmm; a = 21.4477(8) Angstrom, b = 7.1449(2) Angstrom, c = 3.8246(2) Angstrom, and Z = 2) consists of layers built from corner-sharing {(VO2)-O-III(OH)(2)F-2} octahedra connected by the terephthalate linkers. The role of fluorine in this structure is understood by comparison with the already known hybrid vanado(III)carboxylates. The thermal behavior of the two solids has been investigated using TGA and X-ray thermodiffractometry. Finally, magnetic measurements performed on both MIL-71 and MIL-71cal reveal a canted antiferromagnetic behavior with Neel temperatures below 20 K. DICVOL 2003-45 Corma, A Rey, F Valencia, S Jorda, JL Rius, J A zeolite with interconnected 8-, 10- and 12-ring pores and its unique catalytic selectivity NATURE MATERIALS 2, 2003, 493-497. One of the major goals in catalysis is to improve the capabilities of microporous materials. This can be accomplished by synthesizing new zeolites; with controlled pore architectures. In particular, zeolites containing channels of different sizes in the same structure are desirable. Here, we report a zeolite containing fully interconnected 8-, 10- and 12-membered-ring pores, synthesized by combining the structure-directing effect of the organic 1,5-bis-(methylpyrrolidinium)-pentane and the framework isomorphic substitution of germanium for silicon. Analysis of the crystal structure determined by direct methods from synchrotron powder diffraction data reveals 16 independent tetrahedrally coordinated atoms. This thermally and hydrothermally stable zeolite structure, when synthesized in its acidic form by incorporating aluminium in the framework, presents unique catalytic shape-selectivity effects derived from its particular pore topology. DICVOL 2003-46 Stock, N Guillou, N Bein, T Ferey, G Inorganic-organic hybrid compounds: synthesis and crystal structure determination from powder diffraction data of Sn-2[O3PCH2C6H4CH2PO3] SOLID STATE SCIENCES 5, 2003, 629-634. A new tin diphosphonate, Sn-2[O3PCH2C6H4CH2PO3], was hydrothermally synthesized from alpha,alpha'-p-xylenediphosphonic acid and SnC2O4. The structure was solved and refined using X-ray powder diffraction data. It crystallizes in the triclinic space group P (1) over bar, with a = 4.9659(3), b = 5.4916(3), c = 11.1730(6) Angstrom, alpha = 87.841(3), beta = 93.827(4), gamma = 90.652(3)degrees, V = 303.79(8) Angstrom(3), Z = 1, R-WP = 0.107, R-P = 0.081, R-B = 0.075, R-F = 0.056. The structure is built up from [SnO3] polyhedra, containing a stereochemically active lone pair of electrons. These polyhedra are connected to a ladder-like structure by phosphonate groups, RPO32-, and through the organic pact of the diphosphonic acid to a layered structure. Thermogravimetric and IR spectroscopic studies are also presented. DICVOL 2003-47 Sanchez-Migallon, A de la Hoz, A Lopez, C Claramunt, RM Infantes, L Motherwell, S Shankland, K Nowell, H Alkorta, I Elguero, J The structure of N-1-hydroxylophine N-3-oxide (=1-hydroxy-2,4,5-triphenyl-1H-imidazole 3-oxide) in the solid state HELVETICA CHIMICA ACTA 86, 2003, 1026-1039. The crystal structure of 1-hydroxy-2,4,5-triphenyl-1H-imidazole 3-oxide (1) has been determined from laboratory X-ray powder-diffraction data. The two independent molecules in the asymmetric unit form chains via O-H ... O hydrogen bonds related by a twofold screw axis. One of the O ... O distances is extremely short (2.32(1) and 2.43(1) Angstrom). Solid-state NMR spectroscopy (CPMAS) combined with calculation of absolute shieldings (GIAO/B3LW/6-31G*) allowed us to determine that the compound behaves as if the O-H ... O hydrogen bond has the proton in the middle (single-well potential), resulting in the near identity of both N-15-NMR signals. DICVOL 2003-48 Boudaren, C Bataille, T Auffredic, JP Louer, D Synthesis, structure determination from powder diffraction data and thermal behaviour of titanium(IV) oxalate [Ti2O3(H2O)(2)](C2O4)center dot H2O SOLID STATE SCIENCES 5, 2003, 175-182. A titanium(IV) oxalate, [Ti2O3(H2O)(2)](C2O4).H2O, has been synthesised in a polycrystalline form in the course of the study of precursors of PZT type oxides. Its crystal structure has been solved ab initio from powder diffraction data collected with conventional monochromatic X-rays. The symmetry is orthorhombic, space group Cmca, with cell dimensions a = 15.494(2) Angstrom, b = 10.491 (1) Angstrom, c = 9.700(l) Angstrom and Z = 8. The structure consists of inorganic corrugated layers of corner-sharing TiO6 octahedra, which form infinite -Ti-O-Ti- connections, linked together by the oxalate anions. The titanium environment is discussed with regard to bond-valence calculations. The thermal behaviour of this compound has been studied by temperature-dependent X-ray diffraction and thermal analyses. In the course of the dehydration process, the partially dehydrated phase [Ti2O3(H2O)(2)](C2O4) has been isolated and its structure has been solved from in situ X-ray powder diffraction data. Its crystal structure determination has shown that the framework of the precursor is preserved. The complete decomposition scheme into anatase is also described. DICVOL 2003-49 ?? Takata, M Nishibori, E Sakata, M Wang, CR Shinohara, H Sc-2 dimer in IPR-violated C-66 fullerene: a covalent bonded metallofullerene CHEMICAL PHYSICS LETTERS 372, 2003, 512-518 The structure of an IPR-violated metallofullerene Sc-2@C-66 has been determined in the electron density level by the MEM/Rietveld method using synchrotron radiation powder data. The fundamental structure has been obtained by the Rietveld analysis. The cage structure of C-66 has been unambiguously identified as that of Isomer No. 4348. The obtained charge density by the MEM analysis shows that the encapsulated two Sc atoms form the covalent bonded Sc-2 dimer and that the charge density of dimer is overlapping with that of C-66 cage, indicating the existence of a covalent bond character between Sc-2 and the carbon cage. DICVOL 2003-50 ?? Cacela, C Baudot, A Duarte, ML Matos-Beja, AM Silva, MR Paixao, JA Fausto, R Low temperature polymorphism in 3-amino-1-propanol JOURNAL OF MOLECULAR STRUCTURE 649, 2003, 143-153. 3-Amino-1-propanol (3AP) was investigated by differential scanning calorimetry, and low temperature powder X-ray diffraction and Raman spectroscopy. Within the range of temperatures studied (-150-25 degreesC), 3AP was found to be able to crystallize in two monotropic polymorphs. Fast cooling rates produce an amorphous state that, on heating, crystallizes into the metastable polymorph. At higher temperatures, this metastable crystalline phase converts into the stable crystal. Using intermediate cooling rates, 3AP crystallizes as the metastable polymorph, the solid solid transition leading to conversion of this form into the stable polymorph occurring during the subsequent heating. Slower cooling rates enable formation of the stable crystal on cooling. The two crystalline polymorphs were structurally characterized by powder X-ray diffraction and Raman spectroscopy. It was concluded that different conformations are assumed by the individual molecules of 3AP in the two crystalline varieties, with the molecules assuming the all-trans configuration in the metastable crystalline state and having the heavy atom backbone trans but the NH2 and OH groups gauche in the-stable crystal. DICVOL 2003-51 Barthelet, K Riou, D Nogues, M Ferey, G Synthesis, structure, and magnetic properties of two new vanadocarboxylates with three-dimensional hybrid frameworks INORGANIC CHEMISTRY 42, 2003, 1739-1743. (V-III(OH))(2){C6H2(CO2)(4)}.4H(2)O (labeled MIL-60) and VIII(OH){(2)(O2C)C6H2(COOH)(2)}.H2O (labeled MIL-61) were hydrothermally synthesized from mixtures of VCl3, 1,2,4,5-benzenetetracarboxylic acid, and water heated for 3 days at 473 K The structure of MIL-60 was solved from single-crystal X-ray diffraction data in the triclinic centrosymmetric P1 (No. 2) space group with lattice parameters a = 6.3758(5) Angstrom, b = 6.8840(5) Angstrom, c = 9.0254(5) Angstrom, alpha = 69.010(2)degrees, beta = 85.197(2)degrees, gamma = 79.452(2)degrees, V = 363.53(5) Angstrom(3), and Z = 1. The structure of MIL-61 was ab initio determined from an X-ray powder diffraction pattern. MIL-61 crystallizes in the Pnma (No. 62) orthorhombic space group with lattice parameters a = 14.8860(1) Angstrom, b = 6.9164(l) Angstrom, c =10.6669(2) Angstrom, V = 1098.23(3) Angstrom(3), and Z = 4. Both structures contain the same inorganic building block that consists of trans chains Of (VO4)-O-III(OH)(2) octahedra. The three-dimensional frameworks of MIL-60 and MIL-61 are constituted by the linkage of these chains via the organic molecules so delimiting the channels or cages where the water molecules are encapsulated. The magnetic behavior of these two phases is presented: MIL-60 is paramagnetic, and MIL-61 antiferromagnetically orders below T-N = 55(5) K. DICVOL 2003-52 Guillou, N Livage, C van Beek, W Nogues, M Ferey, G A layered nickel succinate with unprecedented hexanickel units: Structure elucidation from powder-diffraction data, and magnetic and sorption properties ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 42, 2003, 644-647. DICVOL 2003-53 Ma, HA Jia, X Cui, QL Pan, YW Zhu, PW Liu, BB Liu, HJ Wang, XC Liu, J Zou, GT Crystal structures of C3N6H6 under high pressure CHEMICAL PHYSICS LETTERS 368, 2003, 668-672. In situ high-pressure energy-dispersive X-ray diffraction (EDXRD) experiments on melamine (C3N6H6) have been carried out using diamond anvil cell (DAC) with synchrotron radiation source. In the pressure range from ambient pressure up to 14.7 GPa, two pressure-induced structure phase transitions, from monoclinic to triclinic structure at about 1.3 GPa and from triclinic to orthorhombic structure at about 8.2 GPa, are observed. The crystal structures of melamine at different pressures are built by using Materials Studio (MS) based on the principle of energy minimization. DICVOL 2003-54 Khan, MS Al-Mandhary, MRA Al-Suti, MK Corcoran, TC Al-Mahrooqi, Y Attfield, JP Feeder, N David, WIF Shankland, K Friend, RH Kohler, A Marseglia, EA Tedesco, E Tang, CC Raithby, PR Collings, JC Roscoe, KP Batsanov, AS Stimson, LM Marder, TB Synthesis and optical characterisation of platinum(II) poly-yne polymers incorporating substituted 1,4-diethynylbenzene derivatives and an investigation of the intermolecular interactions in the diethynylbenzene molecular precursors NEW JOURNAL OF CHEMISTRY 27, 2003, 140-149. A series of 1,4-diethynylbenzene (1) derivatives, H-Cequivalent toC-R-Cequivalent toC-H with R=C6H3NH2 (2), C6H3F(3), C6H2F2-2,5 (4), C6F4 (5), C6H2(OCH3)(2)-2,5 (6) and C6H2 ((OC8H17)-C-n)(2)-2,5 (7) has been synthesised and their crystal structures determined by single crystal (2-5) or powder (6, 7) X-ray diffraction. The Cequivalent toCH...pi(Cequivalent toC) hydrogen bonds dominating structure 1 are gradually replaced by Cequivalent toC-H...F ones with the increase of fluorination (3-->5), or completely replaced by Cequivalent toCH...N and NH...pi(Cequivalent toC) bonds in 2, and Cequivalent toCH...O in 6 and 7. The related platinum-based polymers, trans-[Pt((PBu3)-Bu-n)(2)-Cequivalent toC-R-Cequivalent toC-](n) (R=as above and C6H4,) have been prepared and characterised by spectroscopic methods and thermogravimetry, which show that the amino- and methoxy-derivatives have lowest thermal stability while the fluorinated ones exhibit increasing thermal stability with increasing fluorination. Optical spectroscopic measurements reveal that substituents on the aromatic spacer group do not create strong donor-acceptor interactions along the rigid backbone of the organometallic polymers. DICVOL 2003-55 Nockemann, P Cremer, U Ruschewitz, U Meyer, G Mercurous azide, Hg-2(N-3)(2) ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 629, 2003, 2079-2082. White polycrystalline mercurous azide, Hg-2(N-3)(2), is obtained by combining aqueous solutions of NaN3 and Hg-2(NO3)(2).2H(2)O (made viscuous by addition of tetramethoxysilane and heating at 65 degreesC). The crystal structure was solved and refined from X-ray powder diffraction data (monoclinic, P2(1)/n, a = 596.07(2) pm, b = 1259.07(4) pm, c = 357.95(1) pm, beta 103.253(2)degrees, Z = 2, R-B = 0.0519). Solid Hg-2(N-3)(2) contains, essentially, molecules of that composition with Hg-Hg distances of 254.4(3) pm, Hg-N distances of 218(2) pm and Hg-Hg-N angles of 178.7(6)degrees. Weak intermolecular interactions with Hg-N distances starting at 280(3) pm lead to a three-dimensional structure. 2003-56 Nalini, G Subbanna, GN Row, TNG Studies on n=2 Aurivillius phases: structure of the series Bi3-xLaxTiNbO9 (0 <= x <= 1) MATERIALS CHEMISTRY AND PHYSICS 82, 2003, 663-671. The crystal structures of the solid solutions of Bi3-xLaxTiNbO9 (0 less than or equal to x less than or equal to 1) have been analyzed by powder X-ray diffraction with supporting evidence from selected area electron diffraction (SAD). The structure of the starting member (x = 0) is verified to be in the orthorhombic space group A2(1) am while the end member (x = 1) is determined to crystallize in the centrosymmetric orthorhombic space group Pmcb. The structure of x = 1 phase is solved by ab initio powder diffraction. The intermediate compositions belong to the space group A2(1) am as confirmed by Rietveld refinements. Rietveld refinements on all the compositions reveal that the La3+ ion is disordered only in the A site and not in the [Bi2O2](2+) layer. The tilt in the Ti/NbO6 octahedra decreases with increasing x. 2003-57 ??? Ju, J Lin, JH Li, GB Yang, T Li, HM Liao, FH Loong, CK You, LP Aluminoborate-based molecular sieves with 18-octahedral-atom tunnels ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 42, 2003, 5607-5610 2003-58 ??? AU Yebra-Rodriguez, A Martin-Ramos, JD del Rey, F Viseras, C Lopez-Galindo, A Effect of acid treatment on the structure of sepiolite CLAY MINERALS 38, 2003, 353-360. An ab initio determination of the structure of sepiolite after acid treatment (HCI 0.5 N for 24 h) was carried out using X-ray powder diffraction data. After acid treatment, the sections normal to the a and c axes presented discontinuities, similar to2.25 Angstrom wide, parallel to the (0 10) plane, with no electronic density maxima, thus suggesting that adjacent planes are joined by van der Waals-like residual links. Partial dissolution was detected oil both octahedral and tetrahedral sheets, beginning by breaking the ribbons not along the edges, but in the centre, thus creating a 5.20 x 6.79 Angstrom tunnel along the a axis. By interrupting the tetrahedral sheet, this mechanism changes the phyllosilicate-like nature of the sepiolite to an inosilicate-like structure. 2003-59 ??? Plevert, J Sanchez-Smith, R Gentz, TM Li, HL Groy, TL Yaghi, OM O'Keeffe, M Synthesis and characterization of zirconogermanates INORGANIC CHEMISTRY 42, 2003, 5954-5959. Six new zirconogermanates have been prepared under hydrothermal conditions using amines as bases. There are four new structure types (ASU-n) with a common motif of ZrGe5. ASU-23 is a layered structure: ZrGe3O8(OH)F.[C10H26N4].H2O, space group P2(1)/n, a = 6.7957(8) Angstrom, b = 12.700(1) Angstrom, c = 24.293(3) Angstrom, beta = 97.936(2)degrees, V = 2076.4(4) Angstrom(3). ASU-24 is a pillared layered structure: Zr3Ge6O18(OH2,F)(4)F-2.[C6H18N2](2).[C6H17N2](2).2H(2)O, space group P2(1)/n, a = 7.4249(3) Angstrom, b = 25.198(1) Angstrom, c = 11.3483(5) Angstrom, beta = 90.995(1)degrees, V = 2122.9(2) Angstrom(3). This material has the lowest framework density (FD) of any oxide material that we are aware of (FD = 8.48 metal atoms/nm(3)). Two other materials form three-dimensional open-frameworks, ASU-25: ZrGe3O9.[C3H12N2], space group P112(1)/a, a = 13.1994(4) Angstrom, b = 7.6828(2) Angstrom, c = 11.2373(3) Angstrom, gamma = 91.233(3)degrees, V = 1139.29(5) Angstrom(3). The other is ASU-26: ZrGe3O9.[C2H10N2], space group Pn, a = 13.7611(3) Angstrom, b = 7.7294(2) Angstrom, c = 11.2331(3) Angstrom, beta = 104.793(1)degrees, V = 1155.21(4) Angstrom(3). ASU-25 is related to the mineral umbite K2ZrSi3O9.H2O. The germanium equivalent has been prepared through the inorganic route: K2ZrGe3O9.H2O, space group P2(1)2(1)2(1), a = 13.6432(6) Angstrom, b = 7.4256(3) Angstrom, c = 10.3973(4) Angstrom, V = 1053.33(8) Angstrom(3). The structural relationships between ASU-25 and its inorganic counterpart are described. The thermal decomposition of the germanium umbite generated the cyclic trigermanate K2ZrGe3O9, analogue of the mineral wadeite, crystallizing in the orthorhombic system, a = 7.076 Angstrom, b = 12.123 Angstrom, c = 10.451 Angstrom, V = 904.5 Angstrom(3). 2003-60 Crossland, CJ Evans, JSO Synthesis and characterisation of a new high pressure polymorph of Cu2WS4 CHEMICAL COMMUNICATIONS iss 18, 2003, 2292-2293. In this communication we report the synthesis and structural characterisation of a new body centred polymorph of Cu2WS4 prepared using hydrothermal methods. I-Cu2WS4 crystallises in space group I (4) over bar 2m with cell parameters a = b = 5.44427(8), c = 10.0687(2) Angstrom and has a new structure type containing layers of edge-sharing CuS4 and WS4 tetrahedra. 2003-61 Migdal-Mikuli, A Mikuli, E Hetmanczyk, L Natkaniec, I Holderna-Natkaniec, K Lasocha, W Phase transitions, structural changes and molecular motions in [Zn(NH3)(4)](BF4)(2) studied by neutron scattering, X-ray powder diffraction and nuclear magnetic resonance JOURNAL OF SOLID STATE CHEMISTRY 174, 2003, 357-464. Nuclear magnetic resonance (H-1 NMR and F-19 NMR) measurements performed at 90-295K, inelastic incoherent neutron scattering (IINS) spectra and neutron powder diffraction (NPD) patterns registered at 22-190 K, and X-ray powder diffraction (XRPD) measurements performed at 86-293 K, provided evidence that the crystal of [Zn(NH3)(4)](BF4)(2) has four solid phases. The phase transitions occurring at: T-C3 = 101 K, T-C2 = 117 K and T-C1 = 178 K, as were detected earlier by differential scanning calorimetry (DSC), were connected on one hand only with an insignificant change in the crystal structure and on the other hand with a drastic change in the speed of the anisotropic, uniaxial reorientational motions of the NH3 ligands and BF4- anions (at T-C3 and at T-C2) and with the dynamical orientational order-disorder process ("tumbling") of tetrahedral [Zn(NH3)(4)](2+) and BF4- ions (at T-C1). The crystal structure of [Zn(NH3)(4)](BF4)(2) at room temperature was determined by XRPD as orthorhombic, space group Pnma (No. 62), a = 10.523 Angstrom, b 7.892 Angstrom, c = 13.354 Angstrom and Z = 4. Unfortunately, it was not possible to determine the structure of the intermediate and the low-temperature phase. However, we registered the change of the lattice parameters and unit cell volume as a function of temperature and we can observe only a small deviation from near linear dependence of these parameters upon temperature in the vicinity of the T-C1 phase transition. 2003-62 Kiang, YH Huq, A Stephens, PW Xu, W Structure determination of enalapril maleate Form II from high-resolution X-ray powder diffraction data JOURNAL OF PHARMACEUTICAL SCIENCES 92, 2003, 1844-1853. The crystal structure of polymorphic Form II of enalapril maleate, a potent angiotensin-converting enzyme inhibitor, was determined from high-resolution X-ray diffraction data using the direct space method. Enalapril maleate Form II crystallizes in space group P2(1)2(1)2(1), Z = 4, with unit cell parameters a = 33.9898(3) Angstrom, b = 11.2109(1) Angstrom, c = 6.64195(7) Angstrom, and V = 2530.96(5) Angstrom(3). By treating the molecules as rigid bodies and using the bond lengths and angles obtained from the X-ray single crystal structures of Form I, which were solved almost 20 years ago, the total degrees of freedom of enalapril maleate were reduced from 25 to 12. This reduction in total degrees of freedom allowed the simulated annealing to complete within a reasonable computation time. In the crystal structure of Form II, the crystal packing, hydrogen-bonding pattern, and conformation of enalapril maleate resemble those in the structure of Form I. The crystal packing and conformation of enalapril maleate in the two polymorphic forms may explain the similarity of the thermal properties, C-13 nuclear magnetic resonance, Fourier transform infrared, and Raman spectra of Forms I and II. In both structures, the conformations of the main peptide chains, which are considered responsible for binding the active angiotensin-converting enzyme sites, remain largely unchanged. Lattice energy calculation showed that Form 11 is slightly more stable than Form I by 3.5 kcal/mole. 2003-63 Evans, IR Howard, JAK Evans, JSO alpha-Bi2Sn2O7 - a 176 atom crystal structure from powder diffraction data JOURNAL OF MATERIALS CHEMISTRY 13, 2003, 2098-2103. Pyrochlore-type bismuth tin oxide, Bi2Sn2O7, is a technologically important material used in applications such as catalysis and gas sensing. Its room temperature structure has been solved by a method of simulated annealing of combined X-ray and neutron diffraction data, followed by Rietveld refinement. With 176 crystallographically independent atoms in the asymmetric unit, it is one of the largest structures solved to-date from powder diffraction data. In addition to the number of unique atoms, additional crystallographic difficulty stems from the fact that the true symmetry of this structure is lower than the apparent metric symmetry of the unit cell. 2003-64 Irran, E Bein, T Stock, N Inorganic-organic hybrid materials: synthesis and crystal structure determination from powder diffraction data of Pb-2(O3PCH2C6H4CH2PO3) JOURNAL OF SOLID STATE CHEMISTRY 173, 2003, 293-298. A new lead diphosphonate, Pb-2(O3PCH2C6H4CH2PO3) was hydrothermally synthesized from tetraethyl alpha,alpha'-p-xylenediphosphonate and Pb(NO3)(2). The structure was solved and refined using X-ray powder diffraction data. It crystallizes in the monoclinic space group P2(1)/c, with a = 467.84(2), b = 2007.98(9), c = 639.10(2) pm, beta = 101.020(3)degrees, V = 589.31(4) 10(6) pm, Z = 2 wR(p) = 0.034, R-p = 0.0277 R(F)2 = 0.061, R-F = 0.036. The structure is built from corner-linked [PbO4] polyhedra, containing a lone pair of electrons. These polyhedra are connected to layers by phosphonate groups, RPO32- and through the organic diphosphonic acid to a three-dimensional structure. Thermogravimetric as well as IR spectroscopic studies are also presented. 2003-65 Paul-Boncour, V Filipek, SM Marchuk, I Andre, G Bouree, F Wiesinger, G Percheron-Guegan, A Structural and magnetic properties of ErFe2D5 studied by neutron diffraction and Mossbauer spectroscopy JOURNAL OF PHYSICS-CONDENSED MATTER 15, 2003, 4349-4359. A neutron powder diffraction study of ErFe2D5, synthesized under 1 GPa hydrogen pressure, shows that it crystallizes at room temperature in an orthorhombic structure described by the Pmn2(1) space group with a = 5.42 Angstrom, b = 5.79 Angstrom, c = 8.00 Angstrom. The deuterium atoms order preferentially in some A(2)B(2) and AB(3) interstitial sites. Below 5 K the erbium moments order in a canted magnetic structure, with an erbium moment of 6.6 mu(B) at 1.4 K. The Fe-57 Mossbauer spectra of ErFe2D5 from 4.2 to 300 K indicate that there are no ordered Fe moments at zero field. These results are discussed in relation to the influence of hydrogen absorption on the magnetic interactions. 2003-66 Dinnebier, RE Carlson, S Hanfland, M Jansen, M Bulk moduli and high-pressure crystal structures of minium, Pb3O4, determined by X-ray powder diffraction AMERICAN MINERALOGIST 88, 2003, 996-1002. We report the pressure dependence of the crystal structure of lead tetroxide (P less than or equal to 41.05 GPa, T 298 K) using high-resolution angle-dispersive X-ray powder diffraction. Pb3O4 shows two reversible phase transitions in the measured pressure range. The crystal structures of the modifications identified have in common frameworks of Pb+4O6 octahedra and irregular Pb+2O4+1 respectively Pb2+O6+1 polyhedra. At ambient conditions, Pb3O4 crystallizes in space group P4(2)/mbc (phase 1). Between 0.11 and 0.3 GPa it exhibits a displacive second order phase transition to a structure with space group Pbam (phase II). A second displacive phase transition occurs between 5.54 and 6.6 GPa to another structure with space group Pbam (phase 111) but halved c dimension. A non-linear compression behavior over the entire pressure range is observed, which can be described by two Vinet relations in the ranges from 0.28 to 5.54 GPa and from 6.6 to 41.05 GPa. The extrapolated bulk moduli of the high-pressure phases were determined to be K-0 = 21(2) GPa for phase 11 and K-0 = 91(3) GPa for phase III. The crystal structures of all phases were refined from X-ray diffraction powder data collected at several pressures between 0.06 and 41.05 GPa. Except for their cell dimensions, phases I and 11 were found to be isostructural to the corresponding phases at low temperatures, whereas phase III can be derived from the Sr2PbO4 aristotype. With increasing pressure, the lone pair which is localized at Pb2+ adopts increasingly pure s-character, which is reflected by the similar coordination polyhedra of Ph2+ in Pb3O4 (phase 111) and of Sr2+ in Sr2PbO4. 2003-67 ???? Habereder, T Noth, H Chemistry of boron, part 250 - 2-Triorgano-silyl, -germyl, -stannyl and -plumbyl derivatives of 1,3-diisopropyl-benzo-1,3,2-diazaborolidine and related compounds and their reactions with (eta(2)-C2H4)Pt(PPh3)(2) APPLIED ORGANOMETALLIC CHEMISTRY 17, 2003, 525-538. A series of 1,3-diisopropyl-benzo-1,3,2-diazaborolidines 1-6 carrying ER3 substituents of Group 14 at the boron atom (E = C, Si, Ge, Sn, Pb; R = Me, Ph) have been prepared. Their molecular structures have been determined. As expected, the B-E bond length increases along this series. Moreover, the orientation of the isopropyl groups relative to the ER3 substituent is influenced by the steric demand of these substituents. The B-11 NMR data show a deshielding of the boron nucleus as the atomic weight of E increases. Oxidative addition reactions with (eta(2)-C2H4)Pt(PPh3)(2) were successful only for the bromo derivative I and the trimethylstannyl derivative 5a, they failed for the triphenylsilyl, triphenylgermyl. and triphenylstannyl compounds, indicating that steric effects play an important role in the successful oxidative addition to boryl-substituted bis(triphenylphosphane)platinum(II) complexes. The triphenylplumbyl derivative 6 reacted with (eta(2)-C2H4)Pt(PPh3)(2) to give cis- and trans-diphenyl-bis(triphenylphosphane)platinum besides Ph(Ph3Pb)Pt(PPh3)(2). Obviously, the Pb-C bond is more reactive than the Pb-B bond. Cis-Platinum-boryl complexes were also obtained from (Me2N)(2)B-SnMe3 and (Me2N)(2)B-GeMe3 while the boranes tmpB(SnMe3)(2) and (Pr2NB)-Pr-i(SnMe3)(2) were unreactive. 2003-68 Li, LY Jin, XL Li, GB Wang, YX Liao, FH Yao, GQ Lin, JH Novel rare earth polyborates. 2. Syntheses and structures CHEMISTRY OF MATERIALS 15, 2003, 2253-2260. Three novel hydrated rare earth polyborates, Ln[B8O11(OH)(5)] (Ln = La-Nd) (1), Ln[B9O13-(OH)(4)].H2O (Ln = Pr - Eu) (2), and Ce[B5O8(OH)]NO3.3H(2)O (3) have been synthesized by using boric acid as a flux at 240 degreesC, starting from rare earth oxides or nitrates and an excess of boric acid. All these polyborates crystallize in monoclinic structures (P2(1)/n) and consist of borate sheets as the fundamental unit, that is, [LnB(6)O(11)] sheet in 1 and 2 and [CeB5O9] sheet in 3. The borate sheets all contain a nine-membered borate ring, of which the rare earth cations are located around the center. The borate frameworks in 1 and 3 are two-dimensional, which are interlinked via ionic Ln-O bonds forming 3D structures. While in 2 the borate framework is three-dimensional with small channels filled by water molecules. Annealing the hydrated polyborates I and 2 at moderate temperature leads to two anhydrous pentaborates, alpha-LnB(5)O(9) (4) for Ln = Pr-Eu and beta-LnB(5)O(9) (5) for Ln = La, Ce. The structure of beta-LaB5O9 has been determined by an ab initio method using powder X-ray diffraction data. It crystallizes in a monoclinic structure in the space group P2(1)/c with a = 6.4418(l) Angstrom, b = 11.6888(3) Angstrom, c = 8.1706(2) Angstrom, and beta = 105.167(1)degrees. The structure of beta-LnB(5)O(9) contains buckled nine-membered ring borate sheets that are interlinked by BO3 groups forming a three-dimensional framework. The Eu3+-doped beta-LaB5O9 materials show dominant D-5(0 -->) F-7(2) emission and a low quenching concentration (0.6 at. %). 2003-69 Park, H Barbier, J Hammond, RP Crystal structure and polymorphism of PbAlBO4 SOLID STATE SCIENCES 5, 2003, 565-571. Two polymorphs of the new borate compound, PbAlBO4, have been synthesized in microcrystalline form and their crystal structures have been refined from powder neutron diffraction data. The low-temperature form, alpha-PbAlBO4, crystallizes in the Pnma space group with a = 6.9209(5) Angstrom, b = 5.7134(4) Angstrom, c = 8.0215(6) Angstrom, Z = 4. Its structure is built of straight [010] chains of edge-shared AlO6 octahedra bridged by BO3 groups and Pb2+ cations. The high-temperature form, beta-PbAlBO4, is obtained by heating the a form to 1048 K followed by quenching in air. It crystallizes in the Pbcn space group with a = 7.0423(3) Angstrom, b = 9.8989(3) Angstrom, c = 9.4281(3) Angstrom, Z = 8. The structure of beta-PbAlBO4 contains zig-zag chains of AlO6 octahedra bridged by BO3 groups and Pb2+ cations and is related to the structure of alpha-PbAlBO4 by unit-cell twinning. The detailed crystal chemical analysis of the alpha- and beta-PbAlBO4 structures shows that the alpha-->beta transformation is driven by a decrease in density and the relief of bonding and non-bonding, interactions around the Pb2+ cations. 2003-70 Brunelli, M Wright, JP Vaughan, GRM Mora, AJ Fitch, AN Solving larger molecular crystal structures from powder diffraction data by exploiting anisotropic thermal expansion ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 42, 2003, 2029-2032. 2003-71 Brinks, HW Hauback, BC The structure of Li3AlD6 JOURNAL OF ALLOYS AND COMPOUNDS 354, 2003, 143-147. The structure of Li3AlD6 has been determined by combined synchrotron X-ray and neutron diffraction. The space group is R3 with unit-cell dimensions a = 8.07117(10) and c = 9.5130(2) Angstrom. The structure consists of isolated and close to regular AlD63- octahedra, which are connected via six-coordinated Li. The Al-D distances are 1.734-1.754 Angstrom, and the Li-D distances are 1.892-2.120 Angstrom. The shortest D-D distance of 2.395 Angstrom is found within the octahedra. The structure can be described as a distorted bcc structure of AlD63- units with all tetrahedral sites filled with Li. 2003-72 AU Kongshaug, KO Fjellvag, H Novel coordination polymers based on nickel(II) and 2,6-naphthalenedicarboxylate SOLID STATE SCIENCES 5, 2003, 303-310. The two coordination polymers [Ni(ndc)(lutidine)(2)(H2O)(2)], CPO-3, and [Ni-3(ndc)(3)(pyridine)(4)], CPO-4, were obtained by hydrothermal reactions between 2,6-naphthalenedicarboxylic acid (ndc), 3,4-lutidine and nickel(II) nitrate (CPO-3) and ndc, pyridine and nickel(II) nitrate (CPO-4), respectively. In CPO-3, the combination of octahedral nickel(II) ions and ndc ligands leads to the formation of infinite chains. CPO-4 is based on linear trinuclear building units of octahedral nickel(II) ions that are crosslinked via the ndc ligands to form a 3D-structure. The crystal structure of CPO-3 was solved from synchrotron powder X-ray data, while the crystal structure of CPO-4 was solved from conventional single-crystal X-ray data. Crystal data for CPO-3: monoclinic space group Cc (No. 9), a = 14.8583(2), b = 20.3985(3), c = 10.7258(1) Angstrom, beta = 129.0067(6)degrees, V = 2526.14(5) Angstrom(3) and Z = 4. Crystal data for CPO-4: monoclinic space group P2(1)/c (No. 14), a = 11.491(3), b = 17.917(4), c = 12.781(3) Angstrom, beta = 116.142(7)degrees, V = 2362.2(9) Angstrom(3) and Z = 2. The thermal and magnetic properties of both compounds were investigated. 2003-73 Renaudin, G Bertheville, B Yvon, K Synthesis and structure of an orthorhombic low-pressure polymorph of caesium magnesium hydride, CsMgH3 JOURNAL OF ALLOYS AND COMPOUNDS 353, 2003, 175-179. CsMgH3 was synthesized by heating mixtures of the binary hydrides in an autoclave at 600 K and a hydrogen pressure of 150 bars. Synchrotron X-ray and neutron powder diffraction reveals a new structure having orthorhombic symmetry (space group Pmmn, a = 9.9958(1), b = 6.13271(6), c = 8.57364(9) Angstrom for the hydride). In contrast to the trigonal high-pressure polymorph, magnesium centred [MgH6] octahedrons are condensed into triangular rather than linear [3MgH(3)](3-) trimers, and these trimers are connected via four corners to two-dimensional slabs rather than via six corners to a three-dimensional network. The Mg-D distances in the deuteride range from 1.94 to 1.96 Angstrom at the periphery to 2.00-2.08 Angstrom at the centre of the trimers. The Mg displacements within the octahedrons suggest repulsive Mg2+-Mg2+ interactions. 2003-74 Harvey, HG Teat, SJ Tang, CC Cranswick, LM Attfield, MP Synthesis and characterization of three novel cation-containing (NH4+/(CHNH3+)-H-3-N-7/NH3+C2H4NH3+) aluminum diphosphonates INORGANIC CHEMISTRY 42, 2003, 2428-2439. Three new aluminum diphosphonates (C3H7NH3){AIF[(HO)O2PC2H4PO3]} (1) (orthorhombic, Pnma, a = 8.2048(l) Angstrom, b = 6.90056(6) Angstrom, c = 19.6598(4) Angstrom, Z = 4), (H3NC2H4NH3)[AI(OH)(O3PC2H4PO3)] (2) (monoclinic, P2(1)/n, a = 11.142(3) Angstrom, b = 7.008(2) Angstrom, c = 12.903(5) Angstrom, = 96,24(7)degrees, Z = 4), and (NH4)2[AIF(O3PCH2PO3)](3) (orthorhombic, Cmcm, a = 16.592(2) Angstrom, b = 7.5106(g) Angstrom, c = 7.0021 (9) Angstrom, Z = 4) have been synthesized by solvothermal methods in the presence of linear organic ammonium cations (for 1 and 2) and ammonium cations (for 3) and their structures determined using powder, microcrystal, and single-crystal X-ray diffraction data, respectively. All three materials contain a similar one-dimensional chain motif which is related to that found in the mineral Tancoite. This chain motif consists of corner-sharing octahedra (AIO(4)F(2) for 1 and 3 and AIO(6) for 2) linked together through the bridging CPO3 tetrahedra of the diphosphonate groups. These chains are unusual in that each diphosphonate moiety acts as a bisbidentate ligand that is coordinated to the same two metal centers through both of the O3PC-groups of the diphosphonate ligand. The arrangement of the Tancoite-like chains and charge compensation cations in the structures of compounds 1-3 is seen to be dependent upon the nature of the diphosphonic acid and organoammonium/ammonium cations. Careful selection of these two components may provide a method to design future materials in this system. 2003-75 ????? Jeong, HK Nair, S Vogt, T Dickinson, LC Tsapatsis, M A highly crystalline layered silicate with three-dimensionally microporous layers NATURE MATERIALS 2, 2003, 53-58. Layered silicates with three-dimensional microporosity within the layers have the potential to enable new applications in catalysis, adsorption and ion-exchange. Until now no such materials have been reported. However, here we present the synthesis and structure of AMH-3, a silicate with three-dimensionally microporous layers, obtained in high purity and crystallinity. AMH-3 is composed of silicate layers containing eight-membered rings in all three principal crystal directions, and spaced by strontium cations, sodium cations and water molecules. Because of its three-dimensional pore structure, acid and thermal stability, this layered material could find applications in polymer-silicate composites for membrane applications, for synthesis of combined microporous-mesoporous materials, and for the formation of new zeolites and microporous films. Its existence also opens new possibilities for the synthesis of other layered silicates with multidimensional microporous framework layers. 2003-76 Plevert, J Gentz, TM Groy, TL O'Keeffe, M Yaghi, OM Layered structures constructed from new linkages of Ge-7(O,OH,F)(19) clusters CHEMISTRY OF MATERIALS 15, 2003, 714-718. Three new germanate solids, ASU-19, ASU-20-DAPe, and ASU-20-DACH, have been synthesized under hydrothermal conditions using respectively 1,4-diaminobutane (DAB), 1,5-diaminopentane (DAPe), and 1,4-diaminocyclohexane (DACH) as bases. The structures of ASU-19 and ASU-20-DACH have been characterized by single-crystal X-ray diffraction: ASU-19, Ge14O29X4.[GeOX2].[H(2)DAB](3).3.8H(2)O (X = F or OH), space group P (1) over bar, a = 11.4191(5), b = 12.05250, c = 18.1847(8) Angstrom, alpha = 90.704(1)degrees, beta = 92.635(1)degrees, gamma = 91.389(1)degrees, V = 2499.1(2) Angstrom(3); ASU-20-DACH: Ge7O14X3.[H(2)DACH](1.5).2H(2)O, space group C2/c, a = 15.9525(11), b = 17.5476(12), c = 19.0027(13) Angstrom, beta = 109.446(1)degrees, and V = 5015.90 Angstrom(3). The structure of ASU-20-DAPe, Ge7O14X3.[H(2)DAPe](1.5).H2O, has been determined from X-ray powder diffraction data: space group C2/c, a = 16.3180(5), b = 16.6125(4), c = 17.8898(6) Angstrom, beta = 99.684(2)degrees, V = 4780.5(3) Angstrom(3). All three structures are based on the assembly of the same cluster Ge-7(O,OH,F)(19). The two ASU-20 structures consist of a slab of four-connected clusters. In ASU-19, the same layers are connected pairwise through a GeO2X2 spacer, generating a slab structure, with slab thickness ca. 20 Angstrom. The existence of the same layer in the presence of three different organic bases shows the adaptability of the structures to molecules differing in size, shape, and symmetry. 2003-77 Bie, LJ Wang, YX Lin, JH Loong, CK Richardson, JW You, LP Dong, C Synthesis and structure of n=5 member of the A(n+1)Mn(n)O(3n+3)(A(2)O) series CHEMISTRY OF MATERIALS 15, 2003, 516-522. La4Ba2.6Ca1.4(Mn4Ca)O-19, a novel hexagonal perovskite-intergrowth manganate, was synthesized by solid-state reaction. It crystallizes in the space group C2/m (no. 12) with the lattice parameters of a = 9.8394(4) Angstrom, b = 5.6823(2) Angstrom, c = 15.6435(3) Angstrom, and beta = 102.093(5), cell volume of 855.21(5) Angstrom(3), and Z = 2. The structure was investigated by electron, X-ray, and neutron diffraction techniques and fully resolved by refinements of both X-ray and neutron powder diffraction data. The structure can be described as alternate stacking of 6H-type hexagonal perovskite blocks and graphite-like Ca2O sheets. In the hexagonal perovskite block, Mn and Ca cations occupy the octahedral sites of the corner-shearing and face-shearing octahedra, respectively. Preferred La/Ba and Ca/La substitution at the ratio of 7:3 was observed over specific crystallographic sites. La(4)Ba(2.6)Cal(1.4)(Mn4Ca)O-19 is an n = 5 member of the A(n+1)Mn(n)O(3n+3)(Ca2O) series in which 1/5 of the Mn atoms in the 6H-hexagonal perovskite blocks are replaced by Ca. A structural principle that is based on alternate stacking of close-packed [AO(3)] layers and graphite-like sheets is introduced for structural prediction of new hexagonal perovskite intergrowth compounds. 2003-78 Dinnebier, RE Vensky, S Jansen, M Crystal and molecular structure of rubidium peroxodicarbonate Rb-2[C2O6] CHEMISTRY-A EUROPEAN JOURNAL 9, 2003, 4391-4395. We report the crystal structure of rubidium peroxodicarbonate, which was synthesized by electrocrystallization at T = 257 K, from laboratory X-ray powder diffraction data. The compound crystallizes in the monoclinic space group P2(1)/c with four formula units per unit cell and cell parameters of a=7.9129(1), b=10.5117(1), c=7.5559(1) Angstrom, beta=102.001(1)degrees, and V=614.75(1) Angstrom(3). The packing can be considered as a strongly distorted CsCl type of structure. The conformation of the peroxodicarbonate anion was found to be planar (C-2h symmetry), in contrast to the staggered conformation of the peroxodicarbonate anion in the respective potassium peroxodicarbonate. ne different conformation is attributed to packing effects. 2003-79 Botez, CE Stephens, PW Nunes, C Suryanarayanan, R Crystal structure of anhydrous delta-D-mannitol POWDER DIFFRACTION 18, 2003, 214-218. The crystal structure of anhydrous delta-D-mannitol (C6H14O6) was solved from high-resolution synchrotron X-ray powder diffraction data collected on a mixture containing 20% and 80% w/w of beta- and delta-D-mannitol, respectively. The direct space simulated annealing program PSSP, and Rietveld analysis employing GSAS were used to determine and refine the structure. The polymorph has monoclinic symmetry, space group P2(1) with a = 5.089 41(5) Angstrom, b = 18.2504(2) Angstrom, c = 4.917 02(5) Angstrom, and beta = 118.303(2)degrees. There is one molecule in the irreducible volume of the unit cell. The pattern of hydrogen bonding is significantly different than the previously known a and 8 forms. 2003-80 Friese, K Honnerscheid, A Jansen, M Crystal structure determination of systematically intergrown compounds: Li-5(OH)(2)Br-3 and Li-2(OH)Br ZEITSCHRIFT FUR KRISTALLOGRAPHIE 218, 2003, 536-541. We carried out a structure refinement of a crystal which was composed of two phases. Phase I was up to now unknown and corresponds to Li-5(OH)(2)Br-3 with lattice parameters a = 4.02335(1), c = 21.5638(1) Angstrom, space group Mm2. Phase H is Li-2(OH)Br with lattice parameters a = 4.04594(3) Angstrom and space group Pm3m. The two phases have the a, b-plane in common and consequently part of the reflections overlap systematically. We performed a joint structure refinement of the two phases taking into account all reflections. The structure of Li-5(OH)(2)Br-3 is characterized by anti-perovskite like double layers of composition 2 x Li-2(OH)Br, which alternate with rock-salt like layers of composition LiBr. Results for Li-2(OH)Br are in good agreement with literature and confirm the correctness of the underlying model and the usefulness of the method employed in structure refinement.We carried out a structure refinement of a crystal which was composed of two phases. Phase I was up to now unknown and corresponds to Li-5(OH)(2)Br-3 with lattice parameters a = 4.02335(1), c = 21.5638(1) Angstrom, space group I (4) over bar m2. Phase II is Li-2(OH)Br with lattice parameters a = 4.04594(3) Angstrom and space group Pm (3) over barm. The two phases have the a, b-plane in common and consequently part of the reflections overlap systematically. We performed a joint structure refinement of the two phases taking into account all reflections. The structure of Li-5(OH)(2)Br-3 is characterized by anti-perovskite like double layers of composition 2 x Li-2(OH)Br, which alternate with rock-salt like layers of composition LiBr. Results for Li-2(OH)Br are in good agreement with literature and confirm the correctness of the underlying model and the usefulness of the method employed in structure refinement. 2003-81 Bauer, EM Bellitto, C Ibrahim, SA Mahmoud, MR Righini, G Ni(II)octadecylphosphonate: an inorganic/organic layered weak-ferromagnet POLYHEDRON 22, 2003, 2463-2469. Ni[CH3(CH2)(17)PO3] . H2O was prepared and characterized by several techniques and the magnetic properties were measured by using a SQUID magnetometer. Preliminary refinement of the X-ray diffraction powder data by structure-less Le Bail fitting could be obtained and the compound was found to crystallise in the orthorhombic space group Pmn2(1) with a = 5.478(7) Angstrom, b = 42.31(4) Angstrom, c = 4.725(3) Angstrom. Ni(II)octadecyl phosphonate is lamellar and the structure consists of alternating inorganic and organic layers. The inorganic layers are interspersed by by-layers of the octadecyl substituent and van der Waals contacts are established between them. IR spectroscopy revealed all-trans configuration of the hydrocarbonic chain. A tilt angle of 48.2degrees between the chain axis and the (ac) plane could be estimated. The temperature dependence of the molar susceptibility plotted as 1/chi vs. T is linear above 100 K and it follows the Curie-Weiss law. The Curie, C, constant suggests the presence of Ni(II) ion in the S = I spin state and the negative Weiss, theta, constant is indicative of antiferromagnetic nearest neighbour exchange interactions. Zero-field and field-cooled chi vs. T plots were then recorded. The plots show no overlap below 20 K, thus indicating that the compound is in an ordered magnetic state. The critical temperature has been located at the onset of the X vs. T plot and was found to be T-N = 21 K. The magnetization vs. field plots, measured at different temperatures, provide the indication that the compound is a weak-ferromagnet below TN. 2003-82 Howard, CJ Zhang, ZM Structures and phase transition in the layered perovskite La0.6Sr0.1TiO3: a new orthorhombic structure solved from high-resolution diffraction in combination with group theoretical analysis JOURNAL OF PHYSICS-CONDENSED MATTER 15, 2003, 4543-4553. The crystal structure of the layered perovskite La0.6Sr0.1TiO3 at room temperature has been solved by synchrotron x-ray powder diffraction in combination with group theoretical analysis. The structure is orthorhombic in Cmmm, on a cell with a = 7.7556(l), b = 7.7349(l) and c = 7.7910(l) Angstrom. It is believed that this is also the structure adopted by La2/3TiO3. Pertinent features are the alternation of fully and partly occupied layers of La (Sr) cations, and out-of-phase tilting of the TiO6 octahedra around an axis perpendicular to the direction of the cation ordering. The compound undergoes a second order transition to a tetragonal structure, the transition temperature being estimated as 360degreesC. 2003-83 Ciurchea, D Structure and superconducting properties of (Bi,Pb): 2223 superconductor with 3D excess conductivity INTERNATIONAL JOURNAL OF MODERN PHYSICS B 17, 2003, 2851-2861. The full pattern decomposition method by Le Bail was applied to a single phase orthorhombic (Bi,Pb):2223 superconductor with an accentuated three dimensional excess conductivity The space group Pmam, with the lattice parameters a = 5.2598, b = 5.5381, c = 37.174 Angstrom was found. The Fourier maps derived show that delocalization of the Sr atoms induces terracing of the Cu/Ca/Cu superconducting stacking of 0.3 Angstrom, close to the c-axis coherence length, yielding the three dimensional character of the conduction evidenced by the resistivity measurements. 2003-84 Coste, S Gautier, E Evain, M Bujoli-Doeuff, M Brec, R Jobic, S Kanatzidis, MG NaV1-xP2S6 (x=0.16): A new compound with infinite straight (1/infinity)[V0.837P2S6](-) chains that exfoliate forming gels CHEMISTRY OF MATERIALS 15, 2003, 2323-2327. The new 1D chalcogenophosphate material NaV0.837(6)P2S6 has been synthesized and its structure determined by X-ray powder diffraction analysis. This compound crystallizes in the monoclinic space group P2(1)/n with a = 6.9677(3) Angstrom, b = 5.9059(2) Angstrom, c = 21.4537(s) Angstrom, and beta = 92.962(2)degrees [Z = 4, V = 881.66(8) Angstrom(3)]. The Rietveld refinement led to R-p/R-wp = 0.0208/0.0271 (for 94 parameters refined). The material is isostructural with 1D-NaCrP2S6 and contains infinite (1/infinity)[V0.837(6)P2S6](_) chains consisting of randomly occupied edge-sharing [VS6] octahedra defining zigzag (1/infinity)[VS4] ribbons that are capped by tetradendate [P2S6] ethane-like groups linked to three successive [VS6] polyhedra. Because of the nonstoichiometry of the phase, the charge balance can be written as Na+(V4+)(0.486)(V3+)(0.351)(P4+)(2)(S2-)(6). NaV0.837(6)P2S6 is soluble in strongly polar organic solvents such as N-methylformamide (NMF). The exfoliation of NaV0.837(6)P2S6 in NMF leads to gels or to colored colloidal solutions with complex fluid behavior that depends strongly on concentration. 2003-85 Dinnebier, RE Vensky, S Panthofer, M Jansen, M Crystal and molecular structures of alkali oxalates: First proof of a staggered oxalate anion in the solid state INORGANIC CHEMISTRY 42, 2003, 1499-1507. The molecular and crystal structures of solvent-free potassium, rubidium, and cesium oxalates have been determined ab initio from high-resolution synchrotron and X-ray laboratory powder patterns. In the case of potassium oxalate K2C2O4 (a = 10.91176(7) Angstrom, b = 6.11592(4) Angstrom, c 3.44003(2) Angstrom, orthorhombic, Pbam, Z = 2), the oxalate anion is planar, whereas in cesium oxalate Cs2C2O4 (a = 6.62146(5) Angstrom, b = 11.00379(9) Angstrom, c = 8.61253(7) Angstrom, beta = 97.1388(4)degrees, monoclinic, P2(1)/c, Z = 4) it exhibits a staggered conformation. For rubidium oxalate at room temperature, two polymorphs exist, one (beta-Rb2C2O4) isotypic to potassium oxalate (a = 11.28797(7) Angstrom, b = 6.29475(4) Angstrom, c = 3.62210(2) Angstrom, orthorhombic, Pbam, Z 2) and the other (alpha-Rb2C2O4) isotypic to cesium oxalate (a = 6.3276(1) Angstrom, b = 10.4548(2) Angstrom, c = 8.2174(2) Angstrom, beta = 98.016(1)degrees, monoclinic, P2(1)/c, Z = 4). The potassium oxalate structure can be deduced from the AlB2 type, and the cesium oxalate structure from the Hg99As type, respectively. The relation between the two types of crystal structures and the reason for the different conformations of the oxalate anion are discussed. 2003-86 Wunschel, M Dinnebier, RE Carlson, S Bernatowicz, P van Smaalen, S Influence of the molecular structures on the high-pressure and low-temperature phase transitions of plastic crystals ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 59, 2003, 60-71. The crystal structures of tert-butyl-tris(trimethylsilyl)silane, Si[C(CH3)(3)](1) [Si(CH3)(3)](3) (Bu1), and di-tert-butyl-bis(trimethylsilyl)silane, Si[C(CH3)(3)](2) [Si(CH3)(3)](2) (Bu2), at room temperature and at 105 K have been determined by X-ray powder diffraction; the high-pressure behavior for pressures between 0 and 5 GPa is reported. The room-temperature structures have cubic Fm (3) over barm symmetry (Z = 4) with a = 13.2645 (2) Angstrom, V = 2333.87 (4) Angstrom(3) for Bu1 and a = 12.9673 (1) Angstrom, V = 2180.46 (3) Angstrom(3) for Bu2. The molecules are arranged in a cubic close packing (c.c.p.) and exhibit at least 48-fold orientational disorder. Upon cooling both compounds undergo a first-order phase transition at temperatures T c = 230 (5) K (Bu1) and Tc = 250 (5) K (Bu2) into monoclinic structures with space group P2(1)/n. The structures at 105 K have a = 17.317 (1), b = 15.598 (1), c = 16.385 (1) Angstrom, gamma = 109.477 (4)degrees, V = 4172.7 (8) Angstrom(3) and Z = 8 for Bu1 and a = 17.0089 (9), b = 15.3159 (8), c = 15.9325 (8) Angstrom, gamma = 110.343 (3)degrees, V = 3891.7 (5) Angstrom(3) and Z = 8 for Bu2. The severe disorder of the room-temperature phase is significantly decreased and only a two- or threefold rotational disorder of the molecules remains at 105 K. First-order phase transitions have been observed at pressures of 0.13-0.28 GPa for Bu1 and 0.20-0.24 GPa for Bu2. The high-pressure structures are isostructural to the low-temperature structures. The pressure dependencies of the unit-cell volumes were fitted with Vinet equations of state and the bulk moduli were obtained. At still higher pressures further anomalies in the pressure dependencies of the lattice parameters were observed. These anomalies are explained as additional disorder-order phase transitions. 2003-87 Asthalter, T Franz, H van Burck, U Messel, K Schreier, E Dinnebier, R Structure and dynamics of octamethyl-ethinyl-ferrocene: an organometallic rotator phase JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 64, 2003, 677-684. The onset of dynamics and the structural changes of octamethyl-ethinyl-ferrocene around a solid-solid phase transition at 248 K have been investigated using the novel technique of quasielastic nuclear forward scattering (QNFS) in a temperature range between 61 and 257 K at a photon energy of 14.413 keV, as well as X-ray powder diffraction at various energies. A pronounced hysteresis for both the dynamical and the structural properties is observed and confirmed by differential-scanning calorimetry. We assign the observed phenomena to a first-order transition from a low-symmetry low-temperature phase to a high-symmetry high-temperature plastically crystalline phase with nearly cubic symmetry. Possible mechanisms for this transition are discussed in the light of our results. 2003-88 Harvey, HG Hu, J Attfield, MP Synthesis, structural characterization, and readsorption behavior of a solid solution aluminum phosphite/ethylenediphosphonate series CHEMISTRY OF MATERIALS 15, 2003, 179-188. Members of the new solid solution aluminum phosphite/ ethylenediphosphonate series, Al-2[(O3PC2H4PO3)(1-x)(HPO3)(2x)](H2O)(2)F-2 . H2O (0 less than or equal to x less than or equal to 0.32), have been prepared and fully characterized. The full dehydration behavior of the parent material of this series, Al-2[O-3-PC2H4PO3](H2O)(2)F-2.H2O (x = 0) has been resolved. On heating the material to 230 degreesC the extraframework water is the primary species desorbed and the framework structure remains intact as determined from the crystal structure of the partially dehydrated material, Al-2[O3PC2H4Po3](H2O)(2)F-2.0.51(3)H2O. Above 150 degreesC, but more noticeably above 200 C, framework water is lost, resulting in the formation of 4- and 5-coordinated Al centers. By 340 degreesC all the framework water and some fluorine is lost resulting in the collapse of the crystalline material. The phosphite substituted materials (0 less than or equal to x less than or equal to 0.32) are shown, by diffraction and spectroscopic techniques, to be single-phase solid solutions. Rietveld refinement of the structure of the x = 0.19 member reveals that a random substitution of phosphite groups for diphosphonate species exists throughout the bulk of the material and that the remainder of the framework remains unaltered by incorporation of this moiety. The readsorption behavior of the materials (0 less than or equal to x less than or equal to 0.32) indicates that the temperature at which the extraframework water is first removed decreases as x increases and that the amount of water lost and degree of readsorption increase as x increases. These results indicate that the porosity of the materials can be controlled in a manner conducive to their rational design. 2003-89 ??? Allen, S Warmingham, NR Gover, RKB Evans, JSO Synthesis, structure and thermal contraction of a new low-temperature polymorph of ZrMo(2)(O)8 CHEMISTRY OF MATERIALS 15, 2003, 3406-3410. 2003-90 Meejoo, S Kariuki, BM Kitchin, SJ Cheung, EY Albesa-Jove, D Harris, KDM Structural aspects of the beta-polymorph of (E)-4-formylcinnamic acid: Structure determination directly from powder diffraction data and elucidation of structural disorder from solid-state NMR HELVETICA CHIMICA ACTA 86, 2003, 1467-1477. Among the derivatives of (E)-cinnamic acid for which the solid-state photochemical properties have been studied, (E)-4-formylcinnamic acid (1) has already received much attention. Given the inability to prepare single crystals of the beta-polymorph of 1 that are of suitable size and quality for structural characterization by single-crystal X-ray diffraction, the structure of this material was determined directly from powder X-ray-diffraction data by means of the genetic-algorithm technique for structure solution, followed by Rieveld refinement. High-resolution solid-state C-13-NMR was also applied to elucidate details of structural disorder concerning the orientation of the formyl group, and provided independent support for the disorder model established form the Rietveld refinement. The reported structure establishes that the beta-phase of 1 is not structurally anomalous among photoreactive (E)-cinnamic acid crystals, and finally resolves a long-standing controversy concerning the structural properties of this material. 2003-91 Mora, AJ Fitch, AN Ramirez, BM Delgado, GE Brunelli, M Wright, J Structure of lithium benzilate hemihydrate solved by simulated annealing and difference Fourier synthesis from powder data ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 59, 2003, 378-383. The crystal structure of lithium benzilate hemihydrate (C14H11O3-Li+.0.5H(2)O) was solved from synchrotron powder diffraction data. This compound crystallizes in the monoclinic space group P2(1)/a. The structure was solved via the direct space search for two benzilate fragments using the simulated-annealing program DASH, localization of the lithium ions and water molecule from a difference Fourier map, and a restrained Rietveld refinement (R-wp = 0.0687). The structure is a coordination polymer of [Li-2(C14H11O3) (2).H2O](2) tetramers building helical fourfold one-dimensional channels parallel to [010]. Inside the channels the tetrahedral coordination spheres of the lithium ions contain hydroxyl and carbonyl groups, and water molecules. The water molecule functions as the cohesive entity forming extended hydrogen-bonded chains running along [010], and bifurcated donor hydrogen bonds with the two nearest carboxylates. At the outer edge of the channels, weaker intermolecular C-H...Ph hydrogen bonds along [100] and [001] contribute to the supramolecular aggregation of the structure. 2003-92 Dinnebier, R Muller, J New insights into an old reaction. High-resolution X-ray powder diffraction of Wiberg's aminoalane intermediate INORGANIC CHEMISTRY 42, 2003, 1204-1210. In accordance with the procedure described by E. Wiberg, Me3Al-NH3 was heated as a bulk material in inert atmosphere to give a colorless liquid which slowly loses methane. Close to the end of this elimination reaction, the melt crystallized to give a microcrystalline powder of (Me2AlNH2)(x). The structure of this intermediate has been solved by the method of high-resolution X-ray powder diffraction. The compound crystallizes in the monoclinic space group C2/c with the cell parameters of a = 15.0047(6) Angstrom, b = 8.7500(2) Angstrom, c = 24.4702(8) Angstrom, and beta = 107.290(2)degrees, with eight trimers (Me(2)AINH(2))(3) Per unit cell. These trimers crystallize in a boat conformation in contrast to the known trimers of the same composition where a twist-boat conformation had been found by single crystal determination. Different conformers of (Me2AINH2)3 have been investigated by theoretical methods (HF/6-31G(d), B3LYP/6-31 G(d), B3LYP/6-311G(d,p), MP2(fc)/6-31 G(d), and MP2(fc)/6-311G(d,p)). The twist-boat and the chair conformer correspond to minima at the potential energy surface, whereas the boat conformer corresponds to a first-order transition state (relative energies of 0.45-2.56 kJ/mol (boat) and 6.66-11.91 kJ/mol (chair)). Relaxed scans of the potential energy surface at the HF/6-31G(d) and B3LYP/6-31G(d) levels have shown that the boat conformer (C-s symmetry) connects two enantiomers of the twist-boat form (C-2 symmetry). 2003-94 Jorgensen, JD Avdeev, M Hinks, DG Burley, JC Short, S Crystal structure of the sodium cobaltate deuterate superconductor NaxCoO2 center dot 4xD(2)O (x approximate to 1/3) PHYSICAL REVIEW B 68, iss 21, 2003, 214517 Neutron and x-ray powder diffraction have been used to investigate the crystal structures of a sample of the newly-discovered superconducting sodium cobaltate deuterate compound with composition Na0.31(3)CoO2.1.25(2)D2O and its anhydrous parent compound Na0.61(1)CoO2. The anhydrous parent compound Na0.61(1)CoO2 has two partially occupied Na sites sandwiched, in the same plane, between CoO2 layers. When Na is removed to make the superconducting composition, the Na site that experiences the strongest Na-Co repulsion is emptied while the occupancy of the other Na site is reduced to about one third. The deuterate superconducting compound is formed by coordinating four D2O molecules (two above and two below) to each remaining Na ion in a way that gives Na-O distances nearly equal to those in the parent compound. One deuteron of the D2O molecule is hydrogen bonded to an oxygen atom in the CoO2 plane and the oxygen atom and the second deuteron of each D2O molecule lie approximately in a plane between the Na layer and the CoO2 layers. This coordination of Na by four D2O molecules leads in a straightforward way to ordering of the Na ions and D2O molecules consistent with the observation of additional shorter-range scattering features in the diffraction data. The sample studied here, which has T-c=4.5 K, has a refined composition of Na0.31(3)CoO2.1.25(2)D2O, in agreement with the expected 1:4 ratio of Na to D2O. These results show that the optimal superconducting composition should be viewed as a specific hydrated compound, not a solid solution of Na and D2O (H2O) in NaxCoO2.D2O. The hydrated superconducting compound may be stable over a limited range of Na and D2O concentration, but studies of T-c and other physical properties vs Na or D2O composition should be viewed with caution until it is verified that the compound remains in the same phase over the composition range of the study. 2003-95 Jurgens, B Irran, E Senker, J Kroll, P Muller, H Schnick, W Melem (2,5,8-triamino-tri-s-triazine), an important intermediate during condensation of melamine rings to graphitic carbon nitride: Synthesis, structure determination by X-ray powder diffractometry, solid-state NMR, and theoretical studies JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125, 2003, 10288-10300. Single-phase melem (2,5,8-triamino-tri-s-triazine) C6N7(NH2)(3) was obtained as a crystalline powder by thermal treatment of different less condensed C-N-H compounds (e.g., melamine C3N3(NH2)(3), dicyandiamide H4C2N4, ammonium dicyanamide NH4[N(CN)(2)], or cyanamide H2CN2, respectively) at temperatures up to 450 degreesC in sealed glass ampules. The crystal structure was determined ab initio by X-ray powder diffractometry (Cu Kalpha(1): P2(1)/c (No. 14), a = 739.92(1) pm, b = 865.28(3) pm, c = 1338.16(4) pm, beta = 99.912(2)degrees, and Z = 4). In the solid, melem consists of nearly planar C6N7(NH2)(3) molecules which are arranged into parallel layers with an interplanar distance of 327 pm. Detailed C-13 and N-15 MAS NMR investigations were performed. The presence of the triamino form instead of other possible tautomers was confirmed by a CPPI (cross-polarization combined with polarization inversion) experiment. Furthermore, the compound was characterized using mass spectrometry, vibrational (IR, Raman), and photoluminescence spectroscopy. The structural and vibrational properties of molecular melem were theoretically studied on both the B3LYP and the MP2 level. A structural optimization in the extended state was performed employing density functional methods utilizing LDA and GGA. A good agreement was found between the observed and calculated structural parameters and also for the vibrational frequencies of melem. According to temperature-dependent X-ray powder diffractometry investigations above 560 degreesC, melem transforms into a graphite-like C-N material. 2003-96 Hauback, BC Brinks, HW Jensen, CM Murphy, K Maeland, AJ Neutron diffraction structure determination of NaAlD4 JOURNAL OF ALLOYS AND COMPOUNDS 358, 2003, 142-145. The structure of NaAlD4 has been determined from Rietveld-type refinements of powder neutron diffraction data at 8 and 295 K. The space group is I4(1) la with a = 501.19(l) and c = 1131.47(5) pm at 295 K. The Na atoms are surrounded by eight D atoms from eight different [AlD4](-) tetrahedra in the geometry of a distorted square antiprism. The two different Na-D distances are nearly equal: 240.3(2) and 240.5(2) pm at 8 K and 243.1(2) and 243.9(2) pm at 295 K. The Al-D distance is 162.7(2) and 162.6(2) pm at 8 and 295 K, respectively. 2003-97 Cheung, EY Kitchin, SJ Harris, KDM Imai, Y Tajima, N Kuroda, R Direct structure determination of a multicomponent molecular crystal prepared by a solid-state grinding procedure JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 125, 2003, 14658-14659. 2003-98 Schwarz, U Akselrud, L Rosner, H Ormeci, A Grin, Y Hanfland, M Structure and stability of the modulated phase Sb-II PHYSICAL REVIEW B 67, 2003, iss 21, 214101. The crystal structure of Sb-II has been determined using angle-dispersive x-ray diffraction of synchrotron radiation. The crystal structure comprises an interpenetrating assembly of a tetragonal host sublattice with symmetry I422 and a tetragonal guest sublattice of symmetry I422, which realize common a axes but different c axes. Weak extra peaks that are also reported in recent investigations performed independently are attributed to modulation waves of the atomic positions in both sublattices. A refinement using full profiles of powder-diffraction data was performed in the four-dimensional superspace group L--111(I422):L--111(I422). The structural investigation is accompanied by ab initio full-potential band-structure calculations confirming the experimentally determined modification sequence. Fitting equations of state to the results of these computations generates pressure-volume relations which are in excellent agreement with the experimental data. On the basis of total-energy calculations, an earlier proposed crystal structure of the tetragonal phase has to be reconsidered in the light of the composite arrangement in Sb-II. 2003-99 Hummer, K Puschnig, P Ambrosch-Draxl, C Ab initio study of anthracene under high pressure PHYSICAL REVIEW B 67, 2003, iss 18, 184105. The pressure effect on the internal molecular orientation, the electronic and optical properties of crystalline anthracene is calculated up to 10.2 GPa by performing density-functional calculations. As the only input for our ab initio calculations we use the lattice parameters experimentally determined by x-ray powder diffraction under pressure and optimize the internal geometry with respect to the three angles theta, chi, and delta, which define the orientation of the molecules inside the unit cell. For the optimized structures the isothermal bulk moduli, the electronic band structures, and dielectric tensors as a function of the unit-cell volume are calculated. The structure optimizations using the local-density approximation and the generalized gradient approximation exchange-correlation potentials give very similar results and agree well with the internal geometry determined from experiment. This gives rise to the conclusion that the application of such approximations for the description of organic molecular crystals within density-functional theory is valid. Moreover, the electron distribution clearly shows a finite density between the molecules in the unit cell, which increases with pressure due to the enhancement of the intermolecular interactions. These findings support the interpretation that the bonding mechanism in anthracene is not solely van der Waals interaction. 2003-100 Lotsch, BV Senker, J Kockelmann, W Schnick, W Investigation of structural and dynamic properties of NH4[N(CN)(2)] by means of X-ray and neutron powder diffraction as well as vibrational and solid-state NMR spectroscopy JOURNAL OF SOLID STATE CHEMISTRY 176, 2003, 180-191. The crystal structure, spectroscopic and thermal properties of ammonium dicyanamide NH4[N(CN)(2)] have been thoroughly investigated by means of temperature-dependent single-crystal X-ray and neutron powder diffraction, vibrational and MAS-NMR spectroscopy as well as thermoanalytical measurements. The comprehensive elucidation of structural details is of special interest with respect to the unique solid-state transformation of ammonium dicyanamide into dicyandiamide. This reaction occurs at temperatures >80degreesC and it represents the isolobal analogue of Wohler's historic transformation of ammonium cyanate into urea. NH4[N(CN)(2)] crystallizes in the monoclinic space group P2(1)/c with lattice constants a = 3.7913(8)1 b = 12.412(2), c = 9.113(2) Angstrom, beta = 91.49(2)degrees and Z = 4 (single-crystal X-ray data, T = 200 K). The temperature dependence of the lattice constants shows anisotropic behavior, however, no evidence for phase transitions in the investigated temperature range was observed. The hydrogen positions could be localized by neutron diffraction (10-370 K), and the temperature-dependent behavior of the ammonium group has been analyzed by Rietveld refinements using anisotropic thermal displacement parameters. They were interpreted by utilizing a rigid body model and extracting the libration and translation matrices of the ammonium ion by applying the TLS formalism. The results obtained by the diffraction methods were confirmed and supplemented by vibrational spectroscopy and solid-state 1 5 N and C-13 MAS-NMR investigations. 2003-101 Pospisil, M Capkova, P Weissmannova, H Klika, Z Trchova, M Chmielova, M Weiss, Z Structure analysis of montmorillonite intercalated with rhodamine B: modeling and experiment JOURNAL OF MOLECULAR MODELING 9, 2003, 39-46. The intercalation process and the structure of montmorillonite intercalated with [rhodamine B](+) cations have been investigated using molecular modeling (molecular mechanics and molecular dynamics simulations), X-ray powder diffraction and IR spectroscopy. The structure of the intercalate depends strongly on the concentration of rhodamine B in the intercalation solution. The presence of two phases in the intercalated structure was revealed by modeling and X-ray powder diffraction: (i) phase with basal spacing 18 Angstrom and with bilayer arrangement of guests and (ii) phase with average basal spacing 23 Angstrom and with monolayer arrangement of guests. In both phases the monomeric and dimeric arrangement can coexist in the interlayer space. Three types of dimers in the interlayer structure have been found by modeling: (i) H-dimer (head-to-head arrangement) present in the 18 Angstrom phase, (ii) sandwich type of the head-to-tail arrangement (present in the 23 Angstrom phase) and (iii) J-dimer (head-to-tail arrangement) present in the 23 Angstrom phase. 2003-102 Mairesse, G Roussel, P Vannier, RN Anne, M Nowogrocki, G Crystal structure determination of alpha-, beta- and gamma-Bi4V2O11 polymorphs. Part II: crystal structure of alpha-Bi4V2O11 SOLID STATE SCIENCES 5, 2003, 861-869. The crystal structure of alpha-Bi4V2O11 was solved in the A2 space group and refined using combined X-ray single crystal and neutron powder diffraction data in the following unit cell a = 16.5949(3) Angstrom (3 x a(m) = 5.5316 Angstrom), b = 5.6106(1) Angstrom, c = 15.2707(3) Angstrom, gamma = 90.260(2)degrees. It is built upon [Bi2O2](2+) layers spaced with vanadium-oxygen slabs where the vanadium atoms exhibit three different oxygen environments. The main characteristic of these V-O slabs is a well defined dimeric unit with two trigonal bipyramids sharing one edge and connected to two VO tetrahedra. These rigid blocks extend along [100] and are spaced with a disordered area where different V-O trigonal bipyramids are interconnected. A possible scheme to explain the actual 6a(m) superlattice is proposed. It also accounts for the diffusion lines systematically observed along [100] by SAED. A relationship between the crystal structures of the three Bi4V2O11 polymorphs and their corresponding conductivity is tentatively suggested. 2003-103 Ouyang, X Tsai, TY Chen, DH Huang, QJ Cheng, WH Clearfield, A Ab initio structure study from in-house powder diffraction of a novel ZnS(EN)(0.5) structure with layered wurtzite ZnS fragment CHEMICAL COMMUNICATIONS iss 7, 2003, 886-887. The solvothermal reaction of elemental zinc with sulfur in ethylenediamine ( en) as solvent yields [ZnS.0.5(NH2CH2CH2NH2)], 1, an unprecedented ethylenediamine pillared ZnS layered compound, containing two dimensional (2-D) boat-type 6-membered rings, which was characterized by ab initio structure solution from powder diffraction data (SDPD). 2003-104 Birkett, HE Cherryman, JC Chippendale, AM Evans, JSO Harris, RK James, M King, IJ McPherson, GJ Structural investigations of three triazines: solution-state NMR studies of internal rotation and structural information from solid-state NMR, plus a full structure determination from powder x-ray diffraction in one case MAGNETIC RESONANCE IN CHEMISTRY 41, 2003, 324-336. Three model 2,4,6-tris(amino)-1,3, 5-triazines, structurally related to a dyestuff molecule previously studied by NMR, were synthesized in order to enable the effects of rotamer exchange on the NMR spectra to be investigated in more detail. Two of the compounds are novel. Internal rotation of the triazine ring substituents was studied by variable-temperature solution-state H-1, C-13 and N-15 NMR spectroscopy. All the expected rotamers were detected for each molecule. Rotamer exchange rates varied from slow to fast over the temperature range -40 to 90degreesC, as observed for the dyestuff molecule itself. Solid-state C-13 and N-15 NMR provided information about the structures of the solid molecules. A full crystal structure determination from high-resolution powder x-ray diffraction was achieved for one of the molecules using simulated annealing techniques. Ab initio MO and N-15 NMR chemical shift calculations, based on energy-minimized structures derived from the x-ray structure determination, enabled the effect of intermolecular hydrogen bonding on the N-15 NMR chemical shifts to be studied. The results compared favourably with the experimental solid-state N-15 NMR shifts. 2003-105 Rocquefelte, X Boucher, F Gressier, P Ouvrard, G First-principle study of the intercalation process in the LixV2O5 system CHEMISTRY OF MATERIALS 15, 2003, 1812-1819. A theoretical study of the lithium intercalated LixV2O5 System has been performed using a dual approach, based on A initio calculations and experimental data. Two main aspects have been investigated: the atomic structure of each phase and the voltage of a lithium battery with a positive electrode made of LixV2O5. This approach leads to proposal of the full atomic arrangement for the different phases obtained during the reaction. Particularly, a structural arrangement is proposed for the debated omega-Li3V2O5 phase, based on a full simulation of its X-ray powder diagram. For the first time, an antiferromagnetic ordering is envisioned for xi-Li2V2O5. Finally, a very good simulation of the experimental open circuit voltage (OCV) curve of the battery, from x = 0 to x = 3, is obtained when the magnetic interactions are considered. 2003-106 Vors, JP Gerbaud, V Gabas, N Canselier, JP Jagerovic, N Jimeno, ML Elguero, J The structure of the agrochemical fungicidal 4-chloro-3-(3,5-dichlorophenyl)-1H-pyrazole (RPA 406194) and related compounds TETRAHEDRON 59, 2003, 555-560. The difficulties to obtain convenient monocrystals of the important fungicide RPA 406194 have been overcome by a combination of solid state C-13 NMR, X-ray powder diffraction and molecular modeling. The compound, a 3-aryl tautomer, crystallizes forming infinite chains of molecules bonded by N-H...N hydrogen bonds, leading to needle-shaped crystals. The tautomerism (equilibrium constant and energy barrier) of this compound in solution has been studied. 2003-107 Mairesse, G Roussel, P Vannier, RN Anne, M Pirovano, C Nowogrocki, G Crystal structure determination of alpha, beta and gamma-Bi4V2O11 polymorphs. Part I: gamma and beta-Bi4V2O11 SOLID STATE SCIENCES 5, 2003, 851-859. Using combined X-ray single crystal and neutron powder thermodiffraction data, the crystal structure of the high temperature gamma-form of Bi4V2O11 was confirmed and accurately refined in the I4/mmm space group and that of the beta-form was entirely determined in the centrosymmetric Amam space group. The two-fold superlattice characterising the beta structure is the result of an ordering process involving corner-sharing V-O tetrahedra and disordered trigonal bipyramids. A possible scheme for the gamma <----> beta phase transition is proposed. 2003-108 Wallwork, KS Pring, A Taylor, MR Hunter, BA A model for the structure of the hydrated aluminum phosphate, kingite determined by ab initio powder diffraction methods AMERICAN MINERALOGIST 88, 2003, 235-239. The crystal structure of kingite, Al-3(PO4)(2)(F,OH)(2).8(H2O,OH), a secondary mineral from a Cambrian-Precambrian phosphate deposit at Tom's Quarry, near Kapunda, South Australia, has been determined from a powder sample using synchrotron X-ray diffraction data. The structure was determined ab initio by direct methods and refined to R-Bragg = 0.022 and R-wp = 0.039 using the Rietveld method. The triclinic structure was solved and refined in the space group P (1) over bar1, a = 9.377(1), b = 10.113(1), c = 7.138(1) Angstrom, alpha = 97.60(1), beta = 100.88(1), gamma = 96.01(1)degrees, V = 653.0(1) Angstrom(3), Z = 2. The structure of kingite contains finite strings of three corner sharing Alphi(6) octahedra (where phi represents O, OH-, F-, or H2O). These strings are cross-linked via PO4 tetrahedra to produce layers that are perpendicular to [100]. The layers are linked via hydrogen bonding through H2O located in the interlayer space. Kingite is shown to have a different stoichiometry to that reported earlier. The relationship of kingite to the structures of wavellite, Al-3(PO4)(2)(OH)(3).5H(2)O, and mitryaevaite, Al-5(PO4)(2)[(P,S)O-3(OH,O)](2)F-2(OH)(2)(H2O)(8).6.48H(2)O, are briefly discussed. 2003-109 Serre, C Ferey, G Synthesis and structure determination from powder data of the first organically templated tin(IV) phosphate: MIL-76 or (Sn3O2)-O-IV(H2O)(HPO4)(4).{H2N-C2H4-NH2}(2.5.){H2O}(2) CHEMICAL COMMUNICATIONS iss 15, 2003, 1818-1819. The first organically templated tin(IV) phosphate has been isolated and its structure solved from powder X-ray diffraction data; it exhibits a one-dimensional inorganic network built up from chains of trimers of tin( IV) octahedra on which phosphate tetrahedral groups are grafted interacting with water molecules and organic moieties. 2003-110 Mulagaleev, RF Soloviev, LA Blokhin, AI Kirik, SD Synthesis and structure of [Pd(NH3)(4)][cis-Pd(NH3)(2)(SO3)(2)][Pd(NH3)(3)(SO3)] center dot H2O RUSSIAN JOURNAL OF COORDINATION CHEMISTRY new palladium compound 29, 2003, 256-260. [Pd(NH3)(4)][cis-Pd(NH3)(2)(SO3)(2)][Pd(NH3)(3)(SO3)] . H2O (I) was synthesized and its structure was studied by X-ray powder diffraction method. In the course of the synthesis, the initial trans-diamminesulfite anionic complex is transformed into the cis-configuration. Further heating in aqueous solution results in isomerization of a substance into a neutral complex [Pd(NH3)(3)(SO3)]. Crystals I are triclinic: a = 10.3297(2) Angstrom, b = 14.1062(3) Angstrom, c = 6.853 1(1) Angstrom, alpha = 101.36(0)degrees, beta = 92.74(0)degrees, gamma = 92.71(0)degrees, space group P (1) over bar. Structure I consists of the columns with alternating cis-[pd(NH3)(2)(SO3)(2)](2-) and [Pd(NH3)(3)(SO3)] complexes and [Pd(NH3)(4)](2+) ions between the columns. 2003-111 Ouyang, X Tsai, TY Chen, DH Huang, QJ Cheng, WH Clearfield, A Ab initio structure study from in-house powder diffraction of a novel ZnS(EN)(0.5) structure with layered wurtzite ZnS fragment (pg 886, 2003) CHEMICAL COMMUNICATIONS iss 9, 2003, 1107-1107 2003-112 Laco, JII Structural studies of poly[(2S,3S)-2,3-dimethoxybutylene alkanamide]s POLYMER 44, 2003, 1935-1940. The structural characterization of a series of stereoregular polyamides 4,n (n = 8, 10, 12), which were obtained from polycondensation of (2S,3S)-2,3-dimethoxy-1,4-butanediamine with aliphatic dicarboxylic acids, has been carried out. X-ray diffraction of powder and fiber samples were analyzed together with electron diffraction patterns of single crystals obtained by isothermal crystallization in solution. Experimental results based on lattice parameters data were used to build a preliminary crystal model using the Cerius program. The main characteristic of the proposed model is the presence of intermolecular hydrogen bonds along the crystal a direction, similarly arranged to conventional nylons. 2003-113 Celotti, G Landi, E A misunderstood member of the nagelschmidtite family unveiled: structure of Ca5Na2(PO4)(4) from X-ray powder diffraction data JOURNAL OF THE EUROPEAN CERAMIC SOCIETY 23, 2003, 851-858. During the development of procedures to synthesize carbonate hydroxyapatite with properties resembling those of biological material, a new phase was found to form after high temperature treatments in the presence of sodium. The compound was isolated and analytically characterized, leading to its identification as Ca5Na2(PO4)(4): an analogous Ca-Na phosphate was previously described, but with rather poor diffraction data and uncertain stoichiometry. Accurate XRD powder patterns revealed a hexagonal cell, space group P6(3)mc (186), a = 10.64 Angstrom, c = 21.71 Angstrom, Z = 6, rho = 2.93 g/cm(3), with the a axis double and the c axis triple those of the subcell typical of alpha-phases in the well-known system A(2)XO(4) (or ABXO(4)). The complete structural determination was carried out and the relevant aspects and properties discussed. 2003-114 Grzywa, M Rafalska-Lasocha, A Lasocha, W X-ray powder diffraction data of potassium mu-oxo-bis(oxodiperoxovanadate)(4-) hydrate K-4[O{VO(O-2)(2)}(2)]H2O POWDER DIFFRACTION 18, 2003, 248-251. The potassium mu-Oxo-bis(oxodiperoxovanadate)(4-) hydrate K-4[O{VO(O-2)(2)}(2)]*H2O was prepared, and its X-ray powder diffraction patterns have been recorded at room temperature. The unit cell parameters were refined to a=6.7097(1)Angstrom, b=9.9574(1)Angstrom, c=15.8250(3)Angstrom, beta=93.69(6)degrees, space group P2(1)/c (14). The sample of K4V2O11*H2O was characterized by IR spectroscopy and analytical investigation. Results of crystal structure refinement by Rietveld method are presented; final R-F and R-wp are 13 and 16%, respectively. 2003-115 Wunschel, M Dinnebier, RE Carlson, S Van Smaalen, S High-pressure phase transitions in tetrakis(trimethylsilyl)silane Si[Si(CH3)(3)](4) HIGH PRESSURE RESEARCH 23, 2003, 425-437. The compound tetrakis(trimethylsilyl)silane S-i[Si(CH3,)(3)](4) (TSi) has been studied at room temperature for pressures up to 2 1.5(1) GPa, using X-ray powder diffraction with synchrotron radiation. Three different phases are reported in the investigated pressure range. The c.c.p.-type structure is stable up to a pressure of 0.19(1) GPa (Fm (3) over barm, a = 13.52110)Angstrom, V = 2471.95(1)Angstrom(3), Z = 4 at 0.02(1)GPa). It shows a severe orientational disorder of the molecules. At pressures 0.19(1)-0.71(1)GPa a monoclinic phase (HP1) is found with space group P2(1)/n and Z=8 (a = 17.746(1)Angstrom, b = 16.098(1)Angstrom, c= 16.871(1)Angstrom, gamma = 111.437(5)degrees and V = 4486.3(8) Angstrom(3) at 0.24(1)GPa). Another monoclinic phase (HP2) exists at pressures 0.52(1)-8.67(5)GPa. This phase has a smaller unit cell than the HP1 phase with Z(.)=2 (a =8.3778(8)Angstrom, b=9.1050(7)Angstrom, c= 13.3024(8)Angstrom, gamma= 111.63(1)degrees and V = 943.22(6) Angstrom(3) at 1.73(2)GPa). The pressure dependencies of the unit-cell volumes are successfully described by Mumaghan or Vinet-type equations of state. The structures at different pressures and temperatures of TSi and related compounds are described as distorted superstructures of the c.c.p. arrangement. The occurrence of different superstructures is rationalized as the result of an optimized packing of ordered molecules of various shapes. 2003-116 Fantin, G Fogagnolo, M Bortolini, O Masciocchi, N Galli, S Sironi, A Polymorphism of dehydrocholic acid: crystal structure of the beta-phase and guest-mediated solid phase conversion NEW JOURNAL OF CHEMISTRY 27, 2003, 1794-1800. Dehydrocholic acid may be obtained in two polymorphic forms: alpha and beta. The complete characterization and the crystal structure of the beta-phase (obtained by unconventional powder diffraction methods) are described and discussed. Conversion of the alpha-form into the thermodynamically more stable beta-polymorph may be obtained through a room temperature solvent-mediated process. On the other hand, transformation of the beta-form into the alpha-form is realized through two distinct pathways: via a temperature-mediated process or as a guest-mediated solid state conversion, without the intervention of an amorphous state. R-(+)-Methyl p-tolyl sulfoxide is the guest of choice for this unusual beta-to-alpha transformation. 2003-117 Barea, E Navarro, JAR Salas, JM Masciocchi, N Galli, S Sironi, A [Cu(4-oxopyrimidinate)(2) center dot nH(2)O]infinity: a robust sodalite type metal-organic framework exhibiting a rich host-guest chemistry POLYHEDRON 22, 2003, 3051-3057. Reaction of Cu2+ salts with 4-hydroxypyrimidine (4-Hpymo) in water:ammonia (9:1) solutions at room temperature leads to formation of either [Cu(4-pymo)(2)(NH3)(2)(H2O)(2)] (1) or [Cu(4-pymo)(2)(.)nH(2)O](infinity) (2), depending on which crystal nucleation process occurs. Selective formation of 2 is possible by using non-coordinating Et3N as a base. X-ray diffraction analyses have been performed in both cases showing that 1 is a mononuclear compound in which the heterocyclic ligands monodentately coordinate the copper ions through the N1 nitrogen atom. 2 is a 3D socialite type open framework, in which each 4-pymo ligand bridges two copper ions through both nitrogen atoms in the N,N'-exobidentate mode. Heating 1 at 110 degreesC in air generates an amorphous phase (2a), which shows the same chemical analysis and spectroscopic properties as dehydrated 2. Crystalline [Cu(4-pymo)(2.)nH(2)O](infinity) (2), possesses interesting physico-chemical properties related to its porous nature. Indeed, this material reversibly absorbs N-2 and water vapour with minimal structural changes. 2003-118 2002-lacking previously in the SDPD-Database 2002-1 Ivashkevich, LS Lyakhov, AS Selevich, AE Ilieva, D Lesnikovich, AL The crystal structure Of Y2P4O13 from X-ray powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE, 217, 2002, 605-608. The crystal structure Of Y2P4O13 has been determined. from X-ray powder diffraction data. Y2P4O13 crystallizes in the orthorhombic space group C222(1) (No. 20) with a = 17.2817(7) Angstrom, b = 6.9823(4) Angstrom, c = 8.5391(3) Angstrom, V = 1030.38(8) Angstrom(3), and Z = 4. The structure has been solved by direct methods using EXPO program and refined by FULLPROF package. The final R-Bragg value was 9.1%. The tetraphosphate anion has the point group 2 symmetry. The yttrium atom is seven-coordinated forming strongly distorted octahedron with one bifurcated vertex. There are infinite chains of oxygen-bridged ittrium atoms miming parallel to the b axis and linked together by the tetraphosphate anions with formation of three-dimensional network. TREOR 2002-2 Filaretov, AA Zhizhin, MG Olenev, AV Gurkin, AA Bobylev, AP Lazoryak, BI Danilov, VP Komissarova, LN Hydrothermal synthesis, structures, and properties: Indium hydrogen phosphates (MIn)-In-I(HPO4)(2) (M-I = K, Rb, and NH4) RUSSIAN JOURNAL OF INORGANIC CHEMISTRY 47, 2002, 1773-1789. Mixed hydrogen phosphates KIn(HPO4)(2) (I), beta(2)-RbIn(HPO4)(2) (II), and (NH4)In(HPO4)(2) (III) were prepared in the In2O3-MH2PO4-H3PO4-HF, In2O3-M2CO3-H3PO4-HF (where M = K or Rb), and In2O3(NH4)Cl-H3PO4 systems under hydrothermal conditions (200degreesC, 20 atm, 96 h). The phosphates were characterized by IR and Raman spectroscopy, thermal analysis, and electron probe microanalysis. The structure of compound II was established by single-crystal X-ray diffraction analysis. The crystal structures of compounds I and III were determined by the Rietveld method. All compounds crystallized in the monoclinic system (space group P2(1)/c, Z= 4); a = 9.6232(1) Angstrom, b = 8.2573(1) Angstrom, c = 9.4571(1) Angstrom, beta = 115.72(1)degrees, R-p = 0.0465, R-wp = 0.0619 for I; a = 9.705(2) Angstrom, b = 8.367(2) Angstrom, c = 9.528(2) Angstrom, beta = 116.60(3)degrees, R-1 = 0.0503, wR(2) = 0.1464 for II; a = 9.6651(1) Angstrom, b = 8.2763(1) Angstrom, c = 9.5964(1) Angstrom, beta = 116.146(1)degrees, R-p = 0.0380, R-wp = 0.0553 for III. The structures of indium hydrogen phosphates can be described as a mixed framework {In[HPO4](2)}(3infinity)(-) of octahedra and tetrahedra. Large cavities in the framework are occupied by monovalent cations. Second-harmonic-generation measurements demonstrated that the crystal structures of compounds I-III have a center of symmetry. TREOR 2002-3 Zhang, QA Nakamura, Y Oikawa, K Kamiyama, T Akiba, E New alkaline earth aluminum hydride with one-dimensional zigzag chains of [AlH6]: Synthesis and crystal structure of BaAlH5 INORGANIC CHEMISTRY 41, 2002, 6941-6943. The title hydride and its deuteride were successfully synthesized. The crystal structure of the deuteride was determined by time-of-flight neutron powder diffraction. BaAlD5 crystallizes with a new orthorhombic structure in space group Pna2(1) (No. 33), cell parameters a = 9.194(1) Angstrom, b = 7.0403(9) Angstrom, and c = 5.1061(6) Angstrom, Z = 4. BaAlH5 is the first example that contains one-dimensional zigzag chains of [AlH6] along the crystallographic c axis. TREOR 2002-4 Cunin, F Deudon, C Favier, F Mula, B Pascal, JL First anhydrous gold perchlorato complex: ClO2Au(CIO4)(4). Synthesis and molecular and crystal structure analysis INORGANIC CHEMISTRY 41, 2002, 4173-4178. Chlorine trioxide, Cl2O6, reacts with Au metal, AuCl3, or HAuCl4.nH(2)O to yield the well-defined chloryl salt, ClO2.Au(ClO4)(4). The crystal and molecular structure of ClO2Au(CIO4)(4) was solved by a Rietveld analysis of powder X-ray diffraction data. The salt crystallizes in a monoclinic cell, space group C2/c, with cell parameters a = 15.074(5), b = 5.2944(2), and c = 22.2020(2) Angstrom and beta = 128.325(2). The structure displays discrete ClO2+ ions lying in channels formed by Au(CIO4)(4)(-) stacks. Au is located in a distorted square planar environment: Au-O = 1.87 and 2.06 Angstrom. [ClO4] groups are monodentate with ClOb = 1.53 and ClOt = 1.39 Angstrom (mean distances; O-b, oxygen bonded to Au; O-t, free terminal oxygen). A full vibrational study of the Au(ClO4)(4)(-) anion is supported by DFT calculations. TREOR 2002-5 Filaretov, AA Zhizhin, MG Komissarova, LN Danilov, VP Chernyshev, VV Lazoryak, BI Synthesis and structure of the new ammonium indium phosphate (NH4)In(OH)PO4 JOURNAL OF SOLID STATE CHEMISTRY 166, 2002, 362-368. A new ammonium indium phosphate (NH4)In(OH)PO4 was prepared by hydrothermal reaction in the In2O3-NH4H2PO4-NH3/OH system (T = 200degreesC, autogenous pressure, 7 days). The formula (NH4)In(OH)PO4 was determined on the basis of chemical and thermal analysis (TG/DSC), X-ray powder diffraction and IR-spectroscopy. (NH4)In(OH)PO4 crystallizes in the tetragonal system with space group P4(3)2(1)2 (No. 96), a - 9.4232(1) Angstrom, 11. 1 766(1) Angstrom, V = 992.45(2) Angstrom(3); Z= 8. The crystal structure was refined by the Rietveld method (R-w = 6.35%, R-p = 5.10%). The second-harmonic generation study confirmed that structure of (NH4)In(OH)PO4 does not have a center of symmetry. The cis-InO4(OH)(2) octahedra form helical chains, parallel to the c-axis. The In-O-In bonds are nearly equidistant. The chains are interconnected by phosphate tetrahedra and create tunnels containing the NH4+ ions along the c-axis. (NH4)In(OH)PO4 is isostructural with RbIn(OH)PO4. TREOR 2002-6 Kubota, Y Honda, T Plevert, J Yamashita, T Okubo, T Sugi, Y Synthesis of a new molecular sieve using DABCO-based structure-directing agent CATALYSIS TODAY 74, 2002, 271-279. A new 1,4-diazabicyclo[2.2.2]octane (DABCO)-based quaternary ammonium compound is designed, synthesized, and used as structure-directing agent (SDA) for molecular sieve synthesis. Several 1,1'-alkylenedi(4-aza-1-azonia-2,5-dimethyl-bicyclo [2.2.2] octane) type SDAs are used in all-silica synthesis mixtures. Among the SDAs tested, the use of 1, 1'-butylenedi-(4-aza-1-azonia-2,5 5-dimethylbicyclo[2.2.2]octane) gives a new phase (GUS-1), whereas the use of other SDAs gives zeolite beta ((*)BEA), ZSM-12 (MTW), and ZSM-5 (MR). The GUS-1 is indexed in the orthorhombic crystal class with refined lattice constants a = 16.4206(4) Angstrom, b = 20.0540(4) Angstrom and c = 5.0464(1) Angstrom. The crystalline architecture of GUS-1 shows the same [001] projection of the framework as that of mordenite (MOR), and is characterized by a one-dimensional 12-membered ring channel system that is closely related to the channels of ZSM-12. The GUS-1 is stable to heat upon calcination at 700 degreesC in air. The calcined material exhibits adsorption capacity that is comparable to typical large-pore one-dimensional microporous silicates. The behavior of the SDA during synthesis is also discussed. TREOR 2002-7 Jensen, TR Hazell, RG Christensen, AN Hanson, JC Hydrothermal synthesis of lithium zinc phosphates: Structural investigation of twinned alpha-Li4Zn(PO4)(2) and a high temperature polymorph beta-Li4Zn(PO4)(2) JOURNAL OF SOLID STATE CHEMISTRY 166, 2002, 341-351. The system LiOH:Zn(NO3)(2):H3PO4:H2O was investigated using hydrothermal synthesis techniques in the temperature range 20degreesC < T < 602degreesC and pressure range, 1 < p < 2.8 kbar, and the crystallization fields of some lithium zinc orthophosphates are reported. Small crystals of a twinned lithium zinc phosphate, alpha-Li(4)ZH(PO4)(2) were prepared and a structural investigation was performed using synchrotron X-ray diffraction: monoclinic, space group P2(1) /a, a = 8.096(2) Angstrom, b = 10.242(2) Angstrom, c = 8.106(2) Angstrom, beta = 104.73(3)degrees, V = 650.1(2) Angstrom(3) and Z = 4. The refinement gave R(F) = 0.042 and wR(F-2) = 0.068 based on 968 independent reflections and 616 observed, F-o(2) > 3sigma(F-o(2)) (lambda = 0.9346(1) Angstrom). The cations are tetrahedrally coordinated to oxygen, and the structure can be viewed as layers of regular ZnO4 and PO4 tetrahedra interconnected by more distorted LiO4 tetrahedra. Thermal investigation using in situ powder X-ray diffraction in the temperature range 20degreesC < T < 900degreesC was performed. The reversible phase transition alpha --> Li4Zn(PO4)(2) was observed in agreement with previous investigations. A powder pattern measured at T = 900degreesC was indexed with a triclinic unit cell: space group, P (1) over bar, a = 5.173(3) Angstrom, b = 7.97(1) Angstrom, c = 9.92(1) Angstrom, alpha = 80.9(1)degrees, beta = 126.8(1)degrees and gamma = 106.0(1)degrees, V = 319.8(7) Angstrom(3) and Z = 2. The linear thermal expansion of alpha- and beta-Li4Zn(PO4)(2) are extracted from powder diffraction data in the temperature range RT to 900degreesC. 2002-8 Zhang, QA Nakamura, Y Oikawa, K Kamiyama, T Akiba, E Synthesis and crystal structure of Sr2AlH7: A new structural type of alkaline earth aluminum hydride INORGANIC CHEMISTRY 41, 2002, 6547-6549. The title hydride and its deuteride were successfully synthesized. The heavy atom structure and hydrogen positions were determined respectively by X-ray Powder diffraction and time-of-flight neutron powder diffraction, They crystallize with a new monoclinic structure in space group I2 (No. 5); cell parameters: a = 12.575(1) Angstrom, b = 9.799(1) Angstrom, c = 7.9911(8) Angstrom, beta = 100,270(4)degrees (hydride), a = 12.552(1) Angstrom, b = 9.7826(8) Angstrom, c = 7.9816(7) Angstrom, beta = 100.286(4)degrees (deuteride), Z = 8. Sr2AlH7 is the first example that consists of isolated [AlH6] units and infinite one-dimensional twisted chains of edge-sharing [HSr4] tetrethedra along the crystallographic c axis. 2002-9 Kongshaug, KO Fjellvag, H Coordination polymers constructed from paddle-wheel building units JOURNAL OF SOLID STATE CHEMISTRY 166, 2002, 213-218. The two structurally related coordination polymers [Cu(ndc) (pyridine)], CPO-2-Cu, and [Zn(ndc)(3,4-lutidine)], CPO-2-Zn, were obtained by hydrothermal reactions between 2,6-naphthalenedicarboxylic acid (ndc), pyridine and copper(II) nitrate (CPO-2-Cu) and ndc, 3,4-lutidine and zinc(II) nitrate (CPO-2-Zn), respectively. The compounds are based on the binuclear paddle-wheel building unit. In both compounds these building units are connected into 2D sheets by naphthalene rings. In the third dimension there are weaker interactions involving the axial ligands pyridine and 3,4-lutidine. The sheets are stacked so that large ID channels are formed into which the axial ligands protrude. The crystal structure of CPO-2-Cu was solved from synchrotron powder X-ray data, while the crystal structure of CPO-2-Zn was solved from conventional single-crystal X-ray data. Crystal data for CPO-2-Cu: Monoclinic space group C2/m (No. 12), a = 10.2252(2), b = 19.0915(4), c = 8.0521(2)Angstrom, beta = 98.824(1)degrees, V = 1553.30(7) Angstrom(3) and Z = 4. Crystal data for CPO-2-Zn: Triclinic space group P - 1 (No. 2), a = 7.540(1), b = 10.711(1), c = 11.196(2) Angstrom, alpha - 66.490(5)degrees, beta = 87.265(6)degrees, chi = 88.470(6)degrees, V = 828.2(2)Angstrom(3) and Z = 2. The thermal properties of both compounds were investigated as well as the magnetic properties of CPO-2-Cu. 2002-10 Evans, IR Evans, JSO Howard, JAK Variable temperature structural study of bismuth lead vanadate, BiPb2VO6 JOURNAL OF MATERIALS CHEMISTRY 12, 2002, 2648-2652. At room temperature, monoclinic BiPb2VO6 is a polar, noncentrosymmetric, second harmonic generation active material and its crystal structure is among the more complex to be solved ab initio from powder diffraction data. In its stability range, BiPb2VO6 also exists in a high symmetry, orthorhombic form. Both phases have been structurally characterized by a combination of X-ray and neutron diffraction data. Their mutual relationship, as well as that to the known compounds of the BiM(2)AO(6) (M = Mg, Ca, Mn, Cu, Zn, Pb and A = P, V, As) family, has been established. 2002-11 Moussa, SM Fenton, RR Hunter, BA Kennedy, BJ Polymorphism and phase transitions in bis(glycinato) copper(II). A powder diffraction study AUSTRALIAN JOURNAL OF CHEMISTRY 55, 2002, 331-341. Powder diffraction methods have been used to establish the structures of four known polymorphs of bis(glycinato)copper(II). The two cis-modifications are orthorhombic, and the two trans-complexes are monoclinic. Refinements of the structures, including the location of the hydrogen/deuterium atoms have been achieved utilizing Rietveld analysis of powder data. The cis-monohydrate complex crystallizes in the space group P2(1)2(1)2(1) with lattice parameters a 10.8053(3), b 5.2101(1), and c 13.4983(4) Angstrom. Upon dehydration, contraction along the a- and c- axes and elongation of the b-axis is observed. The anhydrous cis-complex also crystallizes in the space group P212121 with lattice parameters a 10.0673(7), b 5.3152(4), and c 13.212(1) Angstrom. The trans-hydrated complex crystallizes in the space group I2/a with lattice parameters a 14.8218(3), b 5.2321(1), and c 9.6408(2) Angstrom, and beta 87.243(1)degrees. Dehydration of the complex affords the anhydrous modification which crystallizes in the space group P2(1)/c with lattice parameters a 7.0831(6), b 5.1459(4), and c 9.4431(9) Angstrom, and beta 107.506(4)degrees. In all four modifications a network of hydrogen bonds stabilizes the complex. This study illustrates the current capabilities of powder diffraction techniques. 2002-12 Landskron, K Huppertz, H Senker, A Schnick, W Multianvil synthesis, X-ray powder diffraction analysis, P-31-MAS-NMR, and FTIR spektroscopy as well as material properties of gamma-P3N5, a high-pressure polymorph of binary phosphorus(V) nitride, built up from distorted PN5 square pyramids and PN4 tetrahedra ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 628, 2002, 1465-1471. The high-pressure phase gamma-P3N5 was synthesized at a pressure of I I GPa and a temperature of 1500 degreesC in a multianvil apparatus. Partially crystalline P3N5 has been used as a starting material. The crystal structure was solved by direct methods on the basis of X-ray powder diffraction data and it was refined by the Rietveld method (Imm2, a = 1287.21(4), b = 261.312(6), c 440.03(2) pm, Z = 2, R-p = 0.073, wR(p) = 0.094, R-F = 0.048). gamma-phosphorus nitride crystallizes in a three-dimensional network structure built up from corner sharing PN4 tetrahedra and trans-edge sharing distorted PN5 square pyramids. In the P-31-MAS-NMR spectrum two sharp isotropic resonances with an intensity ratio of I : 2.02(5) are observed at -11.95(3) and -101.72(7) ppm, respectively The IR-spectroscopic and thermal properties of gamma-P3N5 are described. Measurement of the Vickers hardness resulted in a value of 9.7(21) GPa for sintered polycrystalline gamma-P3N5, which is significantly higher than that for the partially crystalline normal pressure modification Of P3N5 (5.1(7) GPa). 2002-13 Li, HM Ju, J Lin, JH Synthesis and crystal structure of layered beryllium polyborate H2BeB4O8 CHINESE JOURNAL OF INORGANIC CHEMISTRY 18, 2002, 764-768. A new layered beryllium polyborate H2Be4O8 was synthesized in molten boric acid flux. It crystallizes in the monoclinic space group P2(1)/n with lattice constants a = 17.75640(15) Angstrom, b =4.2948(1) Angstrom, c =7.1532(1) Angstrom, beta = 96. 8797 (9)degrees and V = 541.574 (9) Angstrom(3). The crystal structure, determined by powder X-ray diffraction techniques, is composed of double three-membered ring unit [BeB4O11], which is further connected by corner-sharing to form two-dimensional layers. The two-dimensional layers are stacked along [100] direction and form three-dimensional structure via hydrogen bonding. 2002-14 ??? Bock, H Hinz-Hubner, D Ruschewitz, U Naumann, D Structure of bis(pentafluorophenyl)xenon, Xe(C6F5)(2) ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 41, 2002, 448-450. 2002-15 Grins, J Esmaeilzadeh, S Hull, S Structure and ionic conductivity of Bi6Cr2O15, a new structure type containing (Bi12O14)(n)(8n+) columns and CrO42- tetrahedra JOURNAL OF SOLID STATE CHEMISTRY 163, 2002, 144-150. Powder samples of the Cr6+-containing compound Bi6Cr2O15 were prepared by solid state reaction of Bi2O3 and Cr2O3 in air at 650degreesC. The structure was solved and refined using high-resolution neutron powder diffraction data in space group Ccc2, with anisotropic thermal displacement parameters a = 12.30184(5), h = 19.87492(7), and c = 5.88162(2) Angstrom, V= 1438.0 Angstrom(3), and 126 variables to R-F = 1.8%. Bi6Cr2O15 exhibits a new structure type that contains (Bi12O14)(n)(8n+) columns, of the kind previously found only for phases isotypic with Bi13MO4VO34. Each column is surrounded by eight CrO42- tetrahedra. The ionic conductivity of Bi6Cr2O15 was determined by impedance measurements to be 3.5 X 10(-5) (Omega cm)(-1) at 600degreesC. 2002-16 Solovyov, LA Zaikovskii, VI Shmakov, AN Belousov, OV Ryoo, R Framework characterization of mesostructured carbon CMK-1 by X-ray powder diffraction and electron microscopy JOURNAL OF PHYSICAL CHEMISTRY B 106, 2002, 12198-12202. The model of structure and structural transformation of the mesostructured carbon material CMK-1 was established by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) investigations. The investigations showed that the enantiomeric carbon subframeworks formed within the pores of the MCM48 mesoporous template used for the material synthesis displaced with respect to one another without significant distortions after the dissolution of the silica wall of the template. The model proposed agrees well with TEM images observed. The XRD structural modeling of CMK- I done using the continuous density function technique allowed perfect fit of the calculated to the experimental powder diffraction pattern and provided geometric characteristics of the material texture. The structural characteristics obtained agreed fairly well with TEM analysis and with previously reported adsorption data. 2002-17 Solovyov, LA Shmakov, AN Zaikovskii, VI Joo, SH Ryoo, R Detailed structure of the hexagonally packed mesostructured carbon material CMK-3 CARBON 40, 2002, 2477-2481. Detailed investigation of the ordered mesoporous CMK-3 carbon using XRD structural modeling based on the continuous electron density representation and the Rietveld technique allowed deriving comprehensive and consistent information on the material anatomy. The electron density distribution map agrees with carbon 'bridges', which seem to be attributed to the material interconnecting carbon nanorods in the CMK-3 mesostructure. These carbon 'bridges' are supposed to be derived from former complementary mesopores of the SBA-15 template used. 2002-18 James, M Watson, JN The synthesis and crystal structure of doped uranium brannerite phases U1-xMxTi2O6 (M=Ca2+, La3+, and Gd3+) JOURNAL OF SOLID STATE CHEMISTRY 165, 2002, 261-265. Doped uranium brannerite phases (U1-xMxTi2O6; M = Ca2+, La3+ and Gd3+; x < 0.5) were synthesized at 1400degreesC; the range of solid solution was found to vary depending on whether sintering took place in argon or air. Powder X-ray diffraction revealed that these phases crystallized to form monoclinic (C2/m) structures. In particular, the crystal structures of U0.74Ca0.26Ti2O6 (1) (a = 9.8008(2); b = 3.7276(1); c = 6.8745(1); beta = 118.38(1); V = 220.97(1); Z = 2; R-P = 7.3%; R-B = 4.6%) and U0.55La0.45Ti2O6 (2) (a = 9.8002(7); b = 3.7510(3); c = 6.9990(5); beta = 118.37(4); V = 226.40(3); Z = 2; R-P = 4.5%; R-B = 2.9%) were refined from powder neutron diffraction data, revealing planes of corner and edge-sharing TiO6 octahedra separated by 8-fold coordinate U/M atoms. The oxygen sites within these structures were found to be fully occupied, confirming that the doping of lower valence M atoms occurs in conjunction with the oxidation of U(IV) to U(V). 2002-19 ??? AU Gover, RKB Withers, ND Allen, S Withers, RL Evans, JSO Structure and phase transitions of SnP2O7 JOURNAL OF SOLID STATE CHEMISTRY 166, 2002, 42-48. SnP2O7 is a member of the ZrP2O7 family of materials, several of which show unusual thermal expansion behavior over certain temperature ranges and which show a number of displacive phase transitions on cooling from high temperature. Here we describe the structural properties of SnP2O7 from 100 to 1243K as determined by X-ray and neutron powder diffraction. These studies reveal that SnP2O7 shows two phase transitions in this temperature range. At room temperature the material has a pseudo-cubic 3 X 3 X 3 superstructure. Electron diffraction studies show that the symmetry of this structure is P2(1)3 or lower. On warming to similar to 560 K it undergoes a phase transition to a structure in which the subcell reflections show a triclinic distortion; above 830 K the subcell reflections show a rhombohedral distortion. Significant hysteresis in cell parameters is observed between heating and cooling. The structure of SnP2O7 is discussed with references to other members of the AM(2)O(7) family of materials. 2002-20 Toraya, H Yamazaki, S Simulated annealing structure solution of a new phase of dicalcium silicate Ca2SiO4 and the mechanism of structural changes from alpha-dicalcium silicate hydrate to alpha(L)'-dicalcium silicate via the new phase ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 58, 2002, 613-621. A new phase of dicalcium silicate (Ca2SiO4) was formed by heating alpha-dicalcium silicate hydrate [alpha-Ca-2 (SiO4H)OH = alpha-C-2 SH] at temperatures of similar to663-763 K, and it was transformed into alpha'(L)-Ca2SiO4 (= alpha'(L)-C2S) above similar to1193 K. The crystal structure of the new phase (hereafter called x-C2S) has been determined by simulated annealing and refined by the Rietveld method using synchrotron radiation powder diffraction data. The structure consists of isolated SiO4 tetrahedra and a three-dimensional CaOn polyhedral network, forming a new structural type of dicalcium silicate. A structural change from alpha-C2SH to x-C2S is compelled by large displacements of SiO4 tetrahedra, accompanied by dehydration, in the direction perpendicular to the two-dimensional Ca(O,OH)(n) polyhedral network in alpha-C2SH. With increasing temperature, sizes of CaOn polyhedra in x-C2S become too large to confine Ca atoms at the sixfold to eightfold coordination sites. Then the structure of alpha-C2S is transformed into alpha'(L)-C2S, having eightfold to tenfold coordination sites for the Ca atoms. 2002-21 Harris, KDM Johnston, RL Turner, GW Tedesco, E Cheung, EY Kariuki, BM Recent advances in the opportunities for solving molecular crystal structures directly from powder diffraction data MOLECULAR CRYSTALS AND LIQUID CRYSTALS 389, 2002, 123-129. For those solids that can be prepared only as microcrystalline powders, and are not suitable for investigation by single crystal diffraction methods, it is necessary to carry out structure determination using powder diffraction data. Here we highlight recent developments in the opportunities for solving molecular crystal structures from powder diffraction data, focusing on a direct-space strategy in which a hypersurface based on the powder profile R-factor R-wp is searched using a Genetic Algorithm. Recent fundamental developments are described, and the application of the method is illustrated by the structure determination of two oligopeptide materials. 2002-22 Kaduk, JA Use of the Inorganic Crystal Structure Database as a problem solving tool ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 58, 2002, 370-379. The information in the Inorganic Crystal Structure Database (ICSD) can be used to determine the structures of new compounds by analogy; this database is thus a useful tool for practical problem solving. A model for the structure of (NH4)Fe(CO3)(OH)(2) [Cmcm, a = 6.6154 (6), b = 12.0639 (10), c = 6.0263 (5) Angstrom, Z = 4] was found by searching the ICSD for compounds with C-centered orthorhombic cells and containing C, H, N and O. [Al(H2O)(6)](2)[Al(H2O)(5)(SO4)](2)-(H3O)(2)(SO4)(5) [P (1) over bar, a = 12.5881 (5), b = 13.0726 (5), c = 7.3354 (2) Angstrom, alpha = 108.162 (2), beta = 70.536 (2), gamma = 112.658 (2)degrees, Z = 1] is isostructural to a Cr compound of the same stoichiometry, which was located by searching on the formula type ANX = A4B7X52. Suitable models for MgCl2(H2O)(4) [P2(1)/c, a = 5.9001 (9), b = 7.2709 (7), c = 8.4199 (7) Angstrom, beta = 111.007 (15)degrees, Z = 2], MgCl2(H2O)(2) [C2/m, a = 7.3886 (29), b = 8.5498 (24), c = 3.6488 (17) Angstrom, beta = 98.96 (3)degrees, Z = 2], and MgCl2(H2O) [Pnma, a = 8.899 (7), b = 3.6339 (20), c = 11.398 (8) Angstrom, Z = 4] were located by combining searches on chemistry and formula type. Quantum-chemical calculations were performed on all five structures to locate the H-atom positions and to obtain quantitative understanding of the hydrogen bonding important in all the structures. 2002-23 Not yet in the SDPD-Database for 2001 2001-1 Zaske, L Perrin, MA Leveiller, F Docetaxel: Solid state characterization by X-ray powder diffraction and thermogravimetry JOURNAL DE PHYSIQUE IV, 11, 2001, 221-226. Docetaxel, a stoichiometric hydrate containing three water molecules per molecule of drug substance, is thermodynamically stable under ambient conditions of pressure, temperature and relative humidity. Dehydration of this form was subjected to X-ray powder diffraction (XRPD) and thermogravimetric experiments. To obtain a better understanding of the observed structural changes between trihydrate and dehydrated forms, the crystalline structure of docetaxel was refined using high resolution XRPD data coupled with an ab initio direct space method. DIOCVOL 2001-2 Francis, RJ Jacobson, AJ Synthesis, structure, and properties of a three-dimensional open-framework niobium fluorogermanate (NGH-5) CHEMISTRY OF MATERIALS 13, 2001, 4676-4680. The low-temperature hydrothermal. synthesis and crystal structure of a new open-framework niobium germanate phase is reported. (C6H18N2). Ge2.2Nb0.8O6.8F1.2 (NGH-5) was synthesized from GeO2, Nb2O5, and HF (aq) by using 1,4-trans-diaminocyclohexane (1,4-DACH) as an organic structure directing agent. The structure of NGH-5 was determined ab initio by using powder X-ray diffraction techniques and consists of a negatively charged three-dimensional Nb/Ge/O/F framework containing three orthogonal channel systems. Two of the channels are delimited by 10-membered rings of NbO5F octahedra and GeO4 tetrahedra; the third is delimited by an 8-membered ring. Charge-balancing (C6H18N2)(2+) cations are encapsulated within the framework and are located at the center of the 10-membered ring channels. The NGH-5 framework is characterized by a low framework density and is closely related to the recently reported zirconium germanate ASU-15. 2001-3 Benard-Rocherulle, P Tronel, H Louer, D Structure and thermal behaviour of new potassium and ammonium lanthanum sulfates from X-ray powder diffraction EPDIC 7: EUROPEAN POWDER DIFFRACTION, PTS 1 AND 2 MATERIALS SCIENCE FORUM 378-3, 2001, 476-481. beta -La(NH4)(SO4)(2) crystallises with the monoclinic symmetry [a = 6.9365(4) Angstrom, b = 9.0055(5) Angstrom, c = 5.4541(4) Angstrom, beta = 90.672(8)degrees and V = 340.68(3) Angstrom (3), S.G. Pn, Z = 2]. Its structure has been solved ab initio from X-ray powder diffraction data and refined by the Rietveld method (RF = 0.06 and R-wp = 0.10). The lanthanum atoms are nine-fold coordinated to sulfate oxygen atoms according to a monodentate-bidentate mode. Through bridging sulfate groups, the LaO9 polyhedra are joined into an anionic layer-like structure parallel to (010). To stabilise the structure the NH4+ cations lying between the layers form short contacts with the terminal O atoms in the sulfate groups, The thermal behaviour of beta -La(NH4)(SO4)(2) and alpha -LaK(SO4)(2), investigated by thermodiffractometry, is also described. The ammonium beta phase decomposes into the oxysulfate La2O2SO4 through the departure of ammonium sulfate in the first stage. According to a similar thermal treatment, the potassium a phase transforms into a polymorph (beta) and the phase transition process is reversible upon cooling, The diffraction patterns of these new varieties of LaK(SO4)(2) have been indexed. 2001-4 Kubota, S Yamane, H Shimada, M A powder diffraction study of Sr3Al10SiO20 ACTA CRYSTALLOGRAPHICA SECTION E-STRUCTURE REPORTS ONLINE 57, 2001, 160-161. In tristrontium decaaluminium silicon icosaoxide, Sr3Al10SiO20, (Al,Si)O-4 tetrahedra and AlO6 octahedra form a framework. Sr atoms occupy two large cavities of the framework. Sr2 and Al4 are on sites of 2/m symmetry, Al3 is on a twofold axis and Sr1 is on a mirror plane. The remaining Al and Si atoms are disordered over tetrahedral sites on general positions. 2001-5 Yang, Z Liang, JK Chen, XL Xu, T Xu, YP Synthesis and crystal structure of a new compound: CaGaBO4 JOURNAL OF ALLOYS AND COMPOUNDS 327, 2001, 215-219. A new compound CaGaBO4 was synthesized by solid state reaction at high temperature and its structure was solved by direct methods from X-ray powder diffraction data. The refinement was carried out using the Rietveld method, and the final refinement converged with R-p=10.2% and R-wp=14.5%. It crystallizes in the orthorhombic system with the space group Ccc2 and lattice parameters a=15.473(1) Angstrom, b=8.2940(8) Angstrom, c=5.8392(6) Angstrom, and Z=8. The crystal structure of CaGaBO4 is formed by BO3-triangle groups, GaO4-tetrahedron groups that are linked to chains along the c-axis, and six-coordinated calcium groups, in which there is a channel of similar to5 Angstrom in diameter along the c-axis. The XRD results show that no phase transition occurs between -173 and 227 degreesC. The lattice parameters and expansion coefficients were calculated. 2001-6 Aubauer, C Irran, E Klapotke, TM Schnick, W Schulz, A Senker, J A theoretical and experimental study on the Lewis acid-base adducts (P4E3)center dot(BX3) (E = S, Se; X = Br, I) and (P4Se3)center dot(NbCl5) INORGANIC CHEMISTRY 40, 2001, 4956-4965. The Lewis acid-base adducts (P4E3). (BX3) (E = S, Se; X = Br, I) and (P4Se3). (NbCl5) have been prepared and characterized by Raman, IR, and solid-state P-31 MAS NMR spectroscopy. Hybrid density functional calculations (B3LYP) have been carried out for both the apical and the basal (P4E3). (BX3) (E = S, Se; X = Br, I) adducts. The thermodynamics of all considered species has been discussed. In accordance with solid-state P-31 MAS NMR and vibrational data, the X-ray powder diffraction structures Of (P4S3). (BBr3) [monoclinic, space group P2(1)/m (No. 11), a = 8.8854(l) Angstrom, b = 10.6164(2) Angstrom, c = 6.3682(l) Angstrom, beta = 108.912(1)degrees, V = 568.29(2) Angstrom (3), Z = 2] and (P4S3). (BI3) [orthorhombic, space group Pnma (No. 62), a = 12. 5039(5) Angstrom, b = 11.3388(5) Angstrom, c = 8.9298(4) Angstrom, V = 1266.09(9) Angstrom (3), Z = 4] indicate the formation of an apical P4S3 Complex in the reaction Of P4S3 with BX3 (X = Br, I). Basal adducts are formed when P4Se3 is used as the donor species. Vibrational assignment for the normal modes of these adducts has been made on the basis of comparison between theoretically obtained and experimentally observed vibrational data. 2001-7 ???? Francis, RJ Jacobson, AJ The first organically templated open-framework niobium silicate and germanate phases: Low-temperature hydrothermal syntheses of [(C4N2H11)Nb3SiO10] (NSH-1) and [(C4N2H11)Nb3GeO10] (NGH-1) ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 40, 2001, 2879-2881. 2001-8 Haas, H Jansen, M Synthesis and characterisation of Na5OAsO4 ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 627, 2001, 1013-1016. Na5AsO5 was prepared from a mixture of Na2O and Na4As2O7 by solid state reaction at 500 degreesC in closed silver crucibles. The crystal structure (X-ray powder data, profilematching: Pbcm, a = 596.4(1). b = 1643.3(1), c = 642,1(1)pm, Z = 4. R-p = 0.0764- R-wp = 0.1019) shows unchanged AsO43--tetrahedra and strings of cis-condensed ONa6-octahedra. IR and Raman data are given. 2001-9 Haas, H Jansen, M Na4SeO5, a novel Pentaoxoselenate(VI) - Synthesis, charakterisation, and comparison with Na4MoO5 ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 627, 2001, 755-760. Na4SeO5 was prepared by high pressure solid state reaction at 500 degreesC and at a hydrostatic pressure of 2.5 Gpa from a mixture of Na2O and Na2SeO4 in silver crucibles and Na4MoO5 by solid state reaction at 450 degreesC from a mixture of Na2O and MoO3. The crystal structures of both new compounds were solved and refined using X-ray powder methods (Profilematching Na4SeO5: P (1) over bar, a = 988.3(1), b = 988.4(1), c = 558.6(l)pm, a = 9625(1)degrees, beta = 96.24(1)degrees, gamma = 113.41(1)degrees, R-p = 0.0783, R-wp = 0,1037. Profilematching Na4MoO5: pi, a = 999.5(1), b = 1002.0(1), c = 565.1(1) pm, Rp = 0.0623, alpha = 96.54(1)degrees, beta = 96.29(1)degrees, gamma = 113.35(1)degrees, R-p = 0.0623, R-wp = 0.0867), Both compounds contain novel XO54- anions of approximately tetragonal pyramidal shape. The crystal structures are consistent with spectroscopic data (IR, Raman). 2001-10 Wannek, C Harbrecht, B Phase equilibria in the palladium-rich part of the gallium-palladium system. The crystal structures of Ga3Pd7 and Ga1-xPd2+x JOURNAL OF ALLOYS AND COMPOUNDS 316, 2001, 99-106. The phase relations between the palladium-rich phases of the gallium-palladium system are clarified by combining preparative methodologies with powder X-ray diffraction and thermochemical analyses. A modified phase diagram of the palladium-rich part of the system is presented. The structure of Ga3Pd7, decomposing peritectoidally at 881(2)degreesC, was determined by powder X-ray diffraction and refined by a Rietveld profile fit. Ga3Pd7 adopts a new structure type with monoclinic space group symmetry: C2/m, Z = 2, a = 1359.46(2) pm, b=405.510(5) pm, c=544.339(6) pm, beta =105.2219(7)degrees, wR(p) = 0.082. The structure can be seen as a strongly distorted, ordered variant of a respective GaxPd1-x fcc solid solution. It comprises two structural motifs: layers of columns of fused (GaPd6/2)(2) prisms are formally separated by equiatomic GaPd layers. The impact of the composition on the structure of Co2Si-type Ga1-xPd2+x was studied. There exists a symmetry relation between the cubic close-packed arrangement of atoms and the structures of the Co2Si-type branch of AB(2) phases with Pearson symbol oP12 and space group symmetry Pnma. 2001-11 Van Tendeloo, G Garlea, O Darie, C Bougerol-Chaillout, C Bordet, P The fine structure of YCuO2+x delafossite determined by synchrotron powder diffraction and electron microscopy JOURNAL OF SOLID STATE CHEMISTRY 156, 2001, 428-436. YCuO2 delafossite crystallizes into two stacking variants; hexagonal 2H or rhombohedral 3R, depending on the preparation conditions. The structure of the fully oxygenated material YCuO2.50 has been determined as orthorhombic (a(O) = 6.1961 Angstrom; b(O) = 11.2158 Angstrom; c(O) = 7.1505 Angstrom; space group Pnma). The structure is based on the hexagonal 2H structure (a(O) = a(H)root3; b(O) = c(H); c(O) = 2a(H)). Upon incomplete oxidation, a different YCuOZ phase with ideal composition YCuO2.33 and lattice parameters a(H root)3, a(H)root3, c(H) is also formed. Diffraction patterns are often very complex because of the presence of planar defects and intergrowth of both phases. Under electron beam irradiation, oxygen is released from the structure and one phase gradually transforms into the other. 2001-12 Boy, I Stowasser, F Schafer, G Kniep, R NaZn(H2O)(2)[BP2O8]center dot H2O: A novel open-framework borophosphate and its reversible dehydration to microporous sodium zincoborophosphate Na[ZnBP2O8]center dot H2O with CZP topology CHEMISTRY-A EUROPEAN JOURNAL 7, 2001, 834-839. Crystals of NaZn(H2O)(2)[BP2O8]. H2O were grown under mild hydrothermal conditions at 170 degrees C. The crystal structure (solved by X-ray single-crystal methods: hexagonal. P6(1)22 (no. 178). a = 946.2(2). c = 158.3.5(1) pm. V = 1227.8(4) 10(6) pm(3). Z = 6) exhibits a chiral octahedral-tetrahedral framework related to the CZP topology and contains helical ribbons of corner-linked berate and phosphate tetrahedra. Investigation of the thermal behavior up to 180 degrees C shows a (reversible) dehydration process: this leads to the microporous compound Na[ZnBP2O8].H2O. which has the CZP topology. The crystal structure of Na[ZnBP2O8].H2O was determined by X-ray powder diffraction by using a combination of simulated annealing, lattice-energy minization, and Rietveld refinement procedures (hexagonal, P6(1)22 (no. 178), a = 954.04(2), c = 1477.80(3) pm, V = 1164.88(5) . 106 pm(3), Z = 6). The essential structural difference caused by the dehydration concerns the coordination of Zn3+ changing from octahedral to tetrahedral arrangement. 2001-13 Amoros, P Marcos, MD Roca, M Alamo, J Beltran-Porter, A Beltran-Porter, D Crystal structure of a new polytype in the V-P-O system: is omega-VOPO4 a dynamically stabilised metastable network? JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS, 62, 2001, 1393-1399. omega -VOPO4 has been prepared by thermal decomposition of different oxovanadium hydrogen phosphates, namely VO(HPO4) nH(2)O (n = 2(alpha), 2(beta) and 4) and beta -NH4(VO2)(HPO4). The omega -VOPO4 phase only remains well crystallised at relatively high temperatures. Its crystal structure has been determined ab initio from X-ray powder diffraction data collected at 4750C. The cell is tetragonal (space group P4(2)/mmc) with a = 4.8552(3) Angstrom and c = 8.4301(6) Angstrom. Starting positional parameters were obtained by direct methods, and the structure was refined using Rietveld profile refinement principles. Disorder of two oxygen sublattices is observed. To rationalise some features of the crystal structure of this new phase, a dynamic model is proposed and discussed. 2001-14 Kongshaug, KO Fjellvag, H Lillerud, KF The synthesis and characterization of a new manganese phosphate templated by piperazine JOURNAL OF SOLID STATE CHEMISTRY 156, 2001, 32-36. An organically templated manganese phosphate, Mn-6(H2O)(2) (HPO4)(4)(PO4)2 .C4N2H12.H2O, has been synthesized hydrothermally and characterized by synchrotron powder X-ray diffraction, thermogravimetric analysis, and magnetic measurements, The compound is structurally closely related to both a magnesium phosphate and an iron phosphate, and crystallizes in the triclinic space group P-1 (No, 2) with a = 12.81926(12) Angstrom, b = 15,87361(20) Angstrom, c = 6.47912(7) Angstrom, a = 99.8660(11)degrees, beta = 90,3913(10)degrees, gamma = 103.4265(9)degrees, V = 1261.928(25) Angstrom (3), and Z = 2, The structure consists of anionic sheets of manganese phosphate separated by piperazinium cations and water molecules, The basic building unit of the inorganic layers is a hexamer of edge-sharing Mn polyhedra. Magnetic susceptibility measurements and bond valence calculations confirm the assignment of high-spin Mn2+ (d(5)) in the title compound. 2001-15 Instruments Ferreira, FF Granado, E Carvalho, W Kycia, SW Bruno, D Droppa, R X-ray powder diffraction beamline at D10B of LNLS: application to the Ba2FeReO6 double perovskite JOURNAL OF SYNCHROTRON RADIATION 13, 2006, 46-53. A new beamline, fully dedicated to X-ray powder diffraction (XPD) measurements, has been installed after the exit port B of the bending magnet D10 at the Brazilian Synchrotron Light Laboratory (LNLS) and commissioned. The technical characteristics of the beamline are described and some performance indicators are listed, such as the incoming photon flux and the angular/energy resolutions obtainable under typical experimental conditions. The results of a Rietveld refinement for a standard sample of Y2O3 using high-resolution data are shown. The refined parameters match those found in the literature, within experimental error. High-resolution XPD measurements on Ba2FeReO6 demonstrate a slight departure from the ideal cubic double-perovskite structure at low temperatures, not detected by previous powder diffraction experiments. The onset of the structural transition coincides with the ferrimagnetic ordering temperature, T(c)similar or equal to 315 K. Subtle structural features, such as those reported here for Ba2FeReO6, as well as the determination and/or refinement of complex crystal structures in polycrystalline samples are ideal candidate problems to be investigated on this beamline. Knapp, M Baehtz, C Ehrenberg, H Fuess, H The synchrotron powder diffractometer at beamline B2 at HASYLAB/DESY: status and capabilities JOURNAL OF SYNCHROTRON RADIATION 11, 2004, 328-334. The synchrotron powder diffraction beamline B2 at HASYLAB/DESY is described. The beamline is capable of high-resolution powder diffraction as well as time-resolved studies and offers several sophisticated ancillary equipments for special applications. A newly developed image-plate system allows for kinetic studies with good resolution in the minutes range. Numerous sample environments allow for various standard applications including structure solution, kinetic studies and in situ observations under flexible and well defined conditions. Representative examples are shown for these setups, which are also supported for experiments of external users. Fitch, AN The high resolution powder diffraction beam line at ESRF JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 109, 2004, 133-142. The optical design and performance of the high-resolution powder diffraction beam line BM16 at ESRF are discussed and illustrated. Some recent studies carried out on BM16 are described, including crystal structure solution and refinement, anomalous scattering, in situ measurements, residual strain in engineering components, investigation of microstructure, and grazing-incidence diffraction from surface layers. The beam line is built on a bending magnet, and operates in the energy range from 5 keV to 40 keV. After the move to an undulator source in 2002, it will benefit from an extented energy range up to 60 keV and increased flux and resolution. It is anticipated that enhancements to the data quality will be achieved, leading to the solution of larger crystal structures, and improvements in the accuracy of refined structures. The systematic exploitation of anisotropic thermal expansion will help reduce the effects of peak overlap in the analysis of powder diffraction data. Krimmer, B Gilles, R Zeitelhack, K Schneider, R Montermann, G Boysen, H Fuess, H A new detector system for the structure powder diffractometer SPODI at the FRM-II in Garching APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING 74, 2002, S154-S156. This article describes the concept of one of the new technical features of the structure powder diffractometer SPODI: the array of position-sensitive detectors including the read-out electronics. 80 single-He3 detectors each with an active length of 300 mm will be arranged vertically in a detector bank. The position sensitivity enables us to evaluate larger parts of the Debye-Scherrer rings and to improve the determination of the 2theta positions of the Bragg peaks. The set-up of this detector system, which is called an individual counter array, is described. Test measurements with the prototype of the read-out electronics are presented. A software package will store the signals in a 2D matrix and allow various evaluation procedures of the data. Special applications 2006 Norrman, M Stahl, K Schluckebier, G Al-Karadaghi, S Characterization of insulin microcrystals using powder diffraction and multivariate data analysis JOURNAL OF APPLIED CRYSTALLOGRAPHY 39, 2006, 391-400. Twelve different microcrystalline insulin formulations were investigated by X-ray powder diffraction and were shown to have very characteristic patterns. Special methods 2006 Hundt, R Schon, JC Jansen, M CMPZ - an algorithm for the efficient comparison of periodic structures JOURNAL OF APPLIED CRYSTALLOGRAPHY 39, 2006, 6-16. The systematic comparison of the atomic structure of solid compounds has become an important task in crystallography, chemistry, physics and materials science, in particular in the context of structure prediction and structure determination of crystalline solids. In this work, an efficient and robust algorithm for the comparison of periodic structures is presented, which is based on the mapping of the point patterns of the two structures into each other. This algorithm has been implemented as the module CMPZ in the structure visualization and analysis program KPLOT. 2005 Earl, DJ Deem, MW Parallel tempering: Theory, applications, and new perspectives PHYSICAL CHEMISTRY CHEMICAL PHYSICS 7, 2005, 3910-3916. We review the history of the parallel tempering simulation method. From its origins in data analysis, the parallel tempering method has become a standard workhorse of physicochemical simulations. We discuss the theory behind the method and its various generalizations. We mention a selected set of the many applications that have become possible with the introduction of parallel tempering, and we suggest several promising avenues for future research. Helliwell, M Jones, RH Kaucic, V Logar, NZ The use of softer X-rays in the structure elucidation of microporous materials JOURNAL OF SYNCHROTRON RADIATION 12, 2005, 420-430. Microporous materials, such as zeolites and aluminophosphates, have many applications as molecular sieves and shape-selective catalysts. This is due to their three-dimensional frameworks, which contain regular pores and channels, to their high acidity, arising from Bronsted and Lewis acid active sites, and to the incorporation of transition metal atoms into framework sites. This review firstly provides an introduction into the nature and properties of these materials, and their important applications; the difficulties in their full characterization and possible methods of elucidating their structures are then outlined; finally, methods of characterization, utilizing 'softer X-rays' are introduced. The first method is the determination of low concentrations of transition metals, incorporated into the frameworks using single crystal anomalous dispersion crystallography; synchrotron radiation is used to tune to the absorption edge of the metal atom in question, in order to change its signal relative to that of the rest of the structure, thereby allowing the pinpointing of its positions and the determination of its concentration at each site in the framework. Secondly, the use of longer wavelengths in powder diffraction studies is described, which, by stretching out the powder pattern, thereby reduces the overlapping of the diffraction peaks, thus allowing the structure to be solved by conventional direct methods. Finally, the use of X-ray absorption spectroscopy to determine the metal incorporation and the nature of coordination at the metal atom sites, in Mn silicalite-1 and FAPO-36, are described. Vaughan, GBM Schmidt, S Poulsen, HF Multicrystal approach to crystal structure solution and refinement ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2005, 813-825. We present a method in which the contributions from the individual crystallites in a polycrystalline sample are separated and treated as essentially single crystal data sets. The process involves the simultaneous determination of the orientation matrices of the individual crystallites in the sample, the subsequent integration of the individual peaks, and filtering and summing of the subsequent integrated intensities, in order to arrive at a single-crystal like data set which may be treated normally. In order to demonstrate the method, we consider as a test case a small molecule structure, cupric acetate monohyrade. We show that it is possible to obtain a single-crystal quality structure solution and refinement, in which accurate anisotropic thermal parameters and hydrogen atom positions are obtained. Brouwer, DH Darton, RJ Morris, RE Levitt, MH A solid-state NMR method for solution of zeolite crystal structures JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 127, 2005, 10365-10370. Since zeolites are notoriously difficult to prepare as large single crystals, structure determination usually relies on powder X-ray diffraction (XRD). However, structure solution (i.e., deriving an initial structural model) directly from powder XRD data is often very difficult due to the diffraction phase problem and the high degree of overlap between the individual reflections, particularly for materials with the structural complexity of most zeolites. Here, we report a method for structure determination of zeolite crystal structures that combines powder XRD and nuclear magnetic resonance (NMR) spectroscopy in which the crucial step of structure solution is achieved using solid-state Si-29 double-quantum dipolar recoupling NMR, which probes the distance-dependent dipolar interactions between naturally abundant Si-29 nuclei in the zeolite framework. For two purely siliceous zeolite blind test samples, we demonstrate that the NMR data can be combined with the unit cell parameters and space group to solve structural models that refine successfully against the powder XRD data. Coelho, AA A bound constrained conjugate gradient solution method as applied to crystallographic refinement problems JOURNAL OF APPLIED CRYSTALLOGRAPHY 38, 2005, 455-461. Small modifications to the conjugate gradient method for solving symmetric positive definite systems have resulted in an increase in performance over LU decomposition by a factor of around 84 for solving a dense system of 1325 unknowns. Performance is further increased in the case of applying upper- and lower-bound parameter constraints. For structure solution employing simulated annealing and the Newton - Raphson method of non-linear least squares, the overall performance gain can be a factor of four, depending on the applied constraints. In addition, the new algorithm with bounding constraints often seeks out lower minima than would otherwise be attainable without constraints. The behaviour of the new algorithm has been tested against the crystallographic problems of Pawley refinement, rigid-body and general crystal structure refinement. Masciocchi, N Sironi, A Structural powder diffraction characterization of organometallic species: the role of complementary information COMPTES RENDUS CHIMIE 8, 2005, 1617-1630. X-ray powder diffraction (XRPD) has been employed in the last years as an active structural tool, well beyond its classical usage in qualitative, quantitative and microstructural analyses. The complexity of the materials studied by this method has steadily grown, allowing the full structural characterization of molecular systems, of organic and organometallic nature. Here we emphasize that, when dealing with such moderately complex molecular materials, the power of XRPD can be enhanced not only by increasing the radiation flux or the instrumental resolution, but also (and cheaply) by using additional (experimental or computational) information. Hofmann, DWM Kuleshova, L New similarity index for crystal structure determination from X-ray powder diagrams JOURNAL OF APPLIED CRYSTALLOGRAPHY 38, 2005, 861-866. A new similarity index for automated comparison of powder diagrams is proposed. In contrast to traditionally used similarity indices, the proposed method is valid in cases of large deviations in the cell constants. The refinement according to this index closes the gap between crystal structure prediction and automated crystal structure determination. The opportunities of the new procedure have been demonstrated by crystal structure solution of un-indexed powder diagrams of some organic pigments (PY111, PR181 and Me-PR170). Trask, AV van de Streek, J Motherwell, WDS Jones, W Achieving polymorphic and stoichiometric diversity in cocrystal formation: Importance of solid-state grinding, powder X-ray structure determination, and seeding CRYSTAL GROWTH & DESIGN 5, 2005, 2233-2241. Solid-state grinding is explored as a means of selectively preparing specific stoichiometric or polymorphic modifications of crystalline supramolecular complexes, or cocrystals. In research involving cocrystals of the model pharmaceutical compound caffeine prepared via solid-state grinding and solution crystallization, it has been demonstrated that these two methods of preparation are not always coterminous with respect to the cocrystal product obtained. Examined herein are the structures of five previously unreported caffeine cocrystals with monocarboxylic acids, including formic acid, acetic acid, and trifluoroacetic acid. This system illustrates three different possibilities in performing cocrystal preparation via the dual methods of solid-state grinding and solution crystallization: (1) the same cocrystal can result from both methods; (2) different cocrystal stoichiometries can result from each method; (3) different cocrystal polymorphs can result from each method. Materials that at first could be prepared only by solid-state grinding were later induced to crystallize from solution by seeding with the grinding material. Because some cocrystals from grinding contained minor residual unreacted starting components, a phase-subtraction method was used to enable subsequent crystal structure determination from powder X-ray diffraction data. The findings herein assign a significance to solid-state grinding as a technique of choice in widespread screening efforts for novel supramolecular materials. Basso, S Fitch, AN Fox, GC Margiolaki, I Wright, JP High-throughput phase-diagram mapping via powder diffraction: a case study of HEWL versus pH ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY 61, 2005, 1612-1625. 44 samples of tetragonal hen egg-white lysozyme (HEWL) were obtained as a series of polycrystalline precipitates at 277 K and room temperature in the pH range between 6.56 and 3.33. The precipitates were investigated by the collection of high-resolution powder X-ray diffraction data at 295 K, which reveal the tetragonal or orthorhombic forms of lysozyme depending on the temperature and pH of crystallization. The use of a new robotic sample changer greatly facilitated these measurements. LeBail analyses of the powder patterns display a characteristic behaviour for the pH dependence of the tetragonal unit-cell parameters of HEWL crystallized at both temperatures. More detailed analysis shows that molecular replacement can give a suitable starting point for structural refinements, illustrating that powder data can be sufficient for this approach. Pawley or Rietveld refinements that fit a single model to four data sets simultaneously from four samples crystallized at pH values across the range studied benefit from improved powder data quality via the anisotropic changes in the unit cell. The Rietveld analysis gave an average structural model with excellent goodness of fit and stereochemistry. Margiolaki, I Wright, JP Fitch, AN Fox, GC von Dreele, RB Synchrotron X-ray powder diffraction study of hexagonal turkey egg-white lysozyme ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY 61, 2005, 423-432. The structure of turkey egg-white lysozyme (TEWL) has been refined from high-resolution X-ray powder diffraction data. The sample was rapidly obtained as a polycrystalline precipitate at high protein concentration using 0.5 M NaCl solvent pH 6 and was deposited in the PDB with code 1xft. The diffraction data were collected at room temperature. Molecular replacement was shown to give a suitable starting point for refinement, illustrating that powder data can be sufficient for this approach. Crystallographic models were then refined by combined Rietveld and stereochemical restraint analysis of the powder data (d(min) = 3.35 angstrom), resulting in the extraction of reliable lattice parameters and the refinement of the molecular conformation at room temperature. The structure is hexagonal [space group P6(1)22, unit-cell parameters a = 71.0862 (3), c = 85.0276 (5) angstrom] with 12 symmetry-related molecules in the unit cell, in agreement with previous studies. The results of our analysis are indicative of specific amino acids being disordered at this temperature. Upon cooling, a sudden drop in the lattice parameters at similar to 250 K is observed concurrently with the freezing of the mother liquor. The observation of severe peak broadening below this temperature indicates strain effects accompanying the freezing transition, which are found to be reversible. Finally, a correlation between the unit-cell parameters and the pH of the buffer solution is evident, in a similar manner to earlier observations on HEWL. Evans, JSO Evans, IR Beyond classical applications of powder diffraction CHEMICAL SOCIETY REVIEWS 33, 2004, 539-547. This article provides a short tutorial review of how laboratory powder diffraction methods can be used to establish a variety of "non-traditional'' pieces of information about solid state materials-information beyond simple phase identification or structure determination at a specific temperature. The examples show how unique insights into synthetic pathways, reaction mechanisms, reaction kinetics, polymorphism, phase transitions and physical properties can be obtained for a variety of different types of materials. Gilmore, CJ Barr, G Paisley, J High-throughput powder diffraction. I. A new approach to qualitative and quantitative powder diffraction pattern analysis using full pattern profiles JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 231-242. A new integrated approach to full powder diffraction pattern analysis is described. This new approach incorporates wavelet-based data pre-processing, non-parametric statistical tests for full-pattern matching, and singular value decomposition to extract quantitative phase information from mixtures. Every measured data point is used in both qualitative and quantitative analyses. The success of this new integrated approach is demonstrated through examples using several test data sets. The methods are incorporated within the commercial software program SNAP-1D, and can be extended to high-throughput powder diffraction experiments. Bhuvanesh, NSP Reibenspies, JH A novel approach to micro-sample X-ray powder diffraction using nylon loops JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 1480-1481. A novel method for sample mounting to obtain powder diffraction from very small amounts of samples ( ranging from micrograms down to a few nanograms), by using a combination of multiwire area detector, three- circle diffractometer, monochromatic Cu K alpha radiation and 10 mum nylon loops, has been developed. This method exploits customary single- crystal approaches to collect the powder diffraction pattern, which overcomes many of the limitations of conventional powder X- ray diffraction. Gozzo, F Schmitt, B Bortolamedi, T Giannini, C Guagliardi, A Lange, M Meister, D Maden, D Willmott, P Patterson, BD First experiments at the Swiss Light Source Materials Science beamline powder diffractometer JOURNAL OF ALLOYS AND COMPOUNDS 362, 2004, 206-217. The Materials Science beamline at the Swiss Light Source saw 'first light' in Spring 2001 and is presently undergoing commissioning and pilot experiment operation. In this article we concentrate on one of the three MS beamline stations, the Powder Diffractometer, and report on resolution tests and first experimental results. Using the high-resolution multi-crystal analyzer detector, full widths at half maximum (FWHM) smaller than 0.01degrees were measured with standard powders and FWHMs smaller than 0.003degrees were measured with a single Si(111) crystal and a very low-divergent incident beam. With the same detector, first residual stress measurements on low pressure plasma sprayed coatings were performed. Dynamic electric field-induced strain effects in relaxor perovskite crystals and the influence of water-soluble polymers on the early hydration of cement were studied using a fast read-out multistrip solid-state detector. Baerlocher, C McCusker, LB Prokic, S Wessels, T Exploiting texture to estimate the relative intensities of overlapping reflections ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 803-812. Additional information about the relative intensities of reflections that overlap in a powder diffraction pattern can be obtained from a polycrystalline sample in which the crystallites are preferentially oriented. If the data are collected and analyzed appropriately, more single-crystal-like reflection intensities can be extracted, and thereby more complex structures solved. This 'texture method' was implemented initially in reflection mode and its power demonstrated with the solution of the 117-atom structure of the hi-h-silica zeolite UTD-1F However, the experiment required a minimum of 3 days of synchrotron beamtime per sample. In an attempt to reduce the amount of beamtime needed and to simplify the experiment itself, a transmission mode alternative using an area detector was developed. Details of the sample preparation, data collection and data analysis for both geometries are described. The solution of the structures of the aluminophosphates Mu-9 (R(3) over bar c, a = 14.0696(1) Angstrom, c = 42.3113(4) Angstrom) and AIPO-M (Pbca, a = 9.7493(1) Angstrom, b = 29.1668(2) Angstrom, c = 9.3528(1) Angstrom) using reflection and transmission mode data, respectively, are provided as examples of the method. Habershon, S Cheung, EY Harris, KDM Johnston, RL An efficient algorithm for calculating whole-profile functions in crystal structure solution from powder diffraction data CHEMICAL PHYSICS LETTERS 390, 2004, 394-398. A method for calculation of the whole-profile powder diffraction R-factor R-wp, adapted specifically for use in direct-space structure solution, is shown to be faster by a factor of approximately 20 than standard methods for calculating R-wp. Dutour, J Guillou, N Huguenard, C Taulelle, F Mellot-Draznieks, C Ferey, G Chiolite, a case study for combining NMR crystallography, diffraction and structural simulation SOLID STATE SCIENCES, 6, 2004, 1059-1067. Chiolite has been selected as a test case for developing a general approach to solve inorganic structures from powders by combining NMR, modeling, and X-ray diffraction. The different steps of the strategy are successfully performed, building the candidate integrant units using NMR, simulating candidate crystal structures using the computational AASBU method, and checking the consistency of the candidate structures against the diffraction data analyzed with FOX computer program. Li, ZG Harlow, RL Foris, CM Li, H Ma, P Vickery, RD Maurin, MB Toby, BH New applications of electron diffraction in the pharmaceutical industry: Polymorph determination by using a combination of electron diffraction and synchrotron X-ray powder diffraction techniques MICROSCOPY AND MICROANALYSIS 8, 2002, 134-138. Electron diffraction has been recently used in the pharmaceutical industry to study the polymorphism in crystalline drug substances. While conventional X-ray diffraction patterns could not be used to determine the cell parameters of two forms of the microcrystalline GP IIb/IIIa receptor antagonist roxifiban, a combination of electron single-crystal and synchrotron powder diffraction techniques were able to clearly distinguish the two polymorphs. The unit-cell parameters of the two polymorphs were ultimately determined using new software routines designed to take advantage of each technique's unique capabilities. The combined use of transmission electron microscopy (TEM) and synchrotron patterns appears to be a good general approach for characterizing complex (low-symmetry, large-unit- cell, micron-sized) polymorphic pharmaceutical compounds. Brenner, S McCusker, LB Baerlocher, C The application of structure envelopes in structure determination from powder diffraction data JOURNAL OF APPLIED CRYSTALLOGRAPHY 35, 2002, 243-252. A structure envelope is a special type of periodic nodal surface that separates regions of high electron density from those of low electron density. Once such a surface has been generated, it can be used in combination with direct-space methods to facilitate structure solution from powder data. To generate an informative structure envelope, the phases of the structure factors of a few strong low-order reflections must be determined; an algorithm has been developed for this purpose. The program SayPerm combines (a) the use of error-correcting codes (e.c.c.'s) to sample phase space efficiently, (b) a pseudo-atom approximation of structure fragments to simulate atomic resolution at ca 2.5 Angstrom, and (c) phase extension and phase set ranking using the Sayre equation. The effect of using a structure envelope in structure solution was first tested in combination with a subroutine for finding zeolite topologies in the program FOCUS. Then extension to molecular structures in combination with a simulated-annealing program was explored. This resulted in the development of the program Safe and the subsequent determination of the structure of a tri-beta-peptide (C32N3O6H53) with 17 variable torsion angles. Brunelli, M Wright, JP Vaughan, GRM Mora, AJ Fitch, AN Solving larger molecular crystal structures from powder diffraction data by exploiting anisotropic thermal expansion ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 42, 2003, 2029-2032. Pichon, C Palancher, H Hodeau, JL Berar, JF Towards operando characterisation by powder diffraction techniques of molecular sieves OIL & GAS SCIENCE AND TECHNOLOGY-REVUE DE L INSTITUT FRANCAIS DU PETROLE 60, 2005, 831-848. Working molecular sieves imply numerous and various atoms and for their characterisation we need chemical selective probes. Thus they can be studied either by neutron powder diffiraction or by anomalous X-ray powder diffiraction techniques to extract structural information. We will illustrate the complementarities of these methods in the analysis of two different chemical processes on X-type zeolite. In the first case, a fully exchanged barium X-type zeolite was, firstly, characterised by neutron powder diffiraction after an ex situ preparation step. During the preparation step, the sample was saturated with a mixture of heavy water and deuterated para-xylene. The selectivity of neutron diffraction for light elements allows the precise location of both water and xylene molecules. In the second example, an X-type zeolite exchanged by both strontium and rubidium cations was studied during the dehydration process. The in situ structural characterisation was performed by recording, for each state of the zeolite (hydrated, dehydrated), three X-ray powder patterns. Two of them were measured at an energy close to the absorption edge of each compensating cation (Sr2+ and Rb+) and one far from both absorption edges. The chemical selectivity of resonant diffraction allows an accurate determination of the distribution of compensating cations (location, distribution and mobility) during the dehydration process. Finally a comparison of some specificities and limitations of both methods are summarized. Schmidt, S Poulsen, HF Vaughan, GBM Structural refinements of the individual grains within polycrystals and powders JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 326-332. A method is presented for simultaneous structural refinement of up to several hundred grains inside powders or polycrystals. The method is based on the use of hard X-rays and the indexing program GRAINDEX, where grain orientations are found by scanning in Euler space. Conventional experimental setups and refinement programs for single-crystal work can be applied. The method is validated by a study of a sintered plate of alpha-Al2O3, containing of the order of 1500 grains in the gauge volume. 57 of the largest grains were refined with respect to the Al z and O x positions as well as the isotropic atomic displacement parameters. The R1 values were 3.4% and 3.8% for the grain average and the best grain, respectively. A discussion of the potential of the method is presented, as well as the main limitation: grain size and overlap of diffraction spots. Indexing 2006 Paszkowicz, W Properties of a genetic algorithm extended by a random self-learning operator and asymmetric mutations: A convergence study for a task of powder-pattern indexing ANALYTICA CHIMICA ACTA 566, 2006, 81-98. Genetic algorithms represent a powerful global-optimisation tool applicable in solving tasks of high complexity in science, technology, medicine, communication, etc. The usual genetic-algorithm calculation scheme is extended here by introduction of a quadratic self-learning operator, which performs a partial local search for randomly selected representatives of the population. This operator is aimed as a minor deterministic contribution to the (stochastic) genetic search. The population representing the trial solutions is split into two equal subpopulations allowed to exhibit different mutation rates (so called asymmetric mutation). The convergence is studied in detail exploiting a crystallographic-test example of indexing of powder diffraction data of orthorhombic lithium copper oxide, varying such parameters as imitation rates and the learning rate. It is shown through the averaged (over the subpopulation) fitness behaviour, how the genetic diversity in the population depends on the mutation rate of the given subpopulation. Conditions and algorithm parameter values favourable for convergence in the framework of proposed approach are discussed using the results for the mentioned example. Further data are studied with a somewhat modified algorithm using periodically varying mutation rates and a problem-specific operator. The chance of finding the global optimum and the convergence speed are observed to be strongly influenced by the effective mutation level and on the self-learning level. The optimal values of these two parameters are about 6 and 5%, respectively. The periodic changes of mutation rate are found to improve the explorative abilities of the algorithm. The results of the study confirm that the applied methodology leads to improvement of the classical genetic algorithm and, therefore, it is expected to be helpful in constructing of algorithms permitting to solve similar tasks of higher complexity. Louer, D Boultif, A Indexing with the successive dichotomy method, DICVOL04 ZEITSCHRIFT FUR KRISTALLOGRAPHIE Suppl. 23, part1, 2006, 225-230. A new version of the program based on the dichotomy principle for powder pattern indexing is reported. The new facilities of the program DICVOL04 include a tolerance for spurious diffraction lines, a refinement of the zero-point shift together with that of cell parameters, an a priori search for a zero-point offset in the input data, a reviewing of all available powder data from the indexing solution found from, generally, the first twenty lines. New strategies have been introduced to limit the risk to miss a solution. The program efficiency is shown with many tests. Additionally, the robustness of the program with respect to the minimum of lines required for finding solutions is presented and examples of two-phases patterns are used to test the performance of the program. Boultif, A History of the dichotomy method for powder pattern indexing POWDER DIFFRACTION 20, 2005, 284-287. A short history of the developments of the successive dichotomy method for powder pattern indexing is presented. In the first computer powder indexing programs (P1 and P2), only high lattice symmetries, down to orthorhombic, were considered [Louer and Louer, J. Appl. Crystallogr. 5, 271-275 (1972)]. Later on, an extension to the monoclinic symmetry was reported in DICVOL, including a partition of the volume space to first search solutions with smaller unit cell volumes [Louer and Vargas, J. Appl. Crystallogr. 15, 542-545 (1982)]. However, CPU times were slow in some monoclinic examples. A thorough mathematical analysis resulted in a significant optimization of the CPU times [Boultif and Louer, J. Appl. Crystallogr. 24, 987-993 (199 1)]. Simultaneously, the method is extended to triclinic lattices. The stages of development of the various versions of the DICVOL program are described, with a particular emphasis on DICVOL91 (Boultif and Louer, 1991) and DICVOL04 [Boultif and Louer, J. Appl. Crystallogr. 37, 724-731 (2004)]. This article is written to testify to and emphasize the major role played by Daniel Louer, who introduced the successive dichotomy method and continued to its evolution and optimization over almost 40 years. 2004 Boultif, A Louer, D Powder pattern indexing with the dichotomy method JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 724-731. The efficiency of the successive dichotomy method for powder diffraction pattern indexing [Louer & Louer (1972). J. Appl. Cryst. 5, 271-275] has been proved over more than 30 years of usage. Features implemented in the new version of the computer program DICVOL04 include (i) a tolerance to the presence of impurity (or inaccurately measured) diffraction lines, (ii) a refinement of the 'zero-point' position, (iii) a reviewing of all input lines from the solution found from, generally, the first 20 lines, (iv) a cell analysis, based on the concept of the reduced cell, to identify equivalent monoclinic and triclinic solutions, and (v) an optional analysis of input powder data to detect the presence of a significant 'zero-point' offset. New search strategies have also been introduced, e. g. each crystal system is scanned separately, within the input volume limits, to limit the risk of missing a solution characterized by a metric lattice singularity. The default values in the input le have been extended to 25 A for the linear parameters and 2500 A 3 for the cell volume. The search is carried out exhaustively within the input parameter limits and the absolute error on peak position measurements. Many tests with data from the literature and from powder data of pharmaceutical materials, collected with the capillary technique and laboratory monochromatic X-rays, have been performed with a high success rate, covering all crystal symmetries from cubic to triclinic. Some examples reported as 'difficult' cases are also discussed. Additionally, a few recommendations for the correct practice of powder pattern indexing are reported. Le Bail, A Monte Carlo indexing with McMaille POWDER DIFFRACTION 19, 2004, 249-254. A Monte Carlo code for indexing powder diffraction patterns is presented. Cell parameters are generated randomly and tested against an idealized powder profile generated from the extracted d's and I's. Mighell, AD Ambiguities in powder indexing: Conjunction of a ternary and binary lattice metric singularity in the cubic system JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 109, 2004, 569-579. A lattice metric singularity occurs when unit cells defining two (or more) lattices yield the identical set of unique calculated d-spacings. The existence of such singularities, therefore, has a practical and theoretical impact on the indexing of powder patterns. For example, in experimental practice an indexing program may find only the lower symmetry member of a singularity. Obviously, it is important to recognize such cases and know how to proceed. Recently, we described: (1) a binary singularity involving a monoclinic and a rhombohedral lattice in a subcell-supercell relationship and (2) a second type of singularity - a ternary singularity - in which two of the three lattices are in a derivative composite relationship. In this work, we describe a ternary lattice metric singularity involving a cubic P, a tetragonal P, and an orthorhombic C lattice. Furthermore, there is a binary singularity, involving a hexagonal P and orthorhombic P lattice, which is characterized by a set of unique d-spacings very close to that of the ternary singularity. The existence of such singularities is more common than once thought and requires a paradigm shift in experimental practice. In addition singularities provide opportunities in material design as they point to highly specialized lattices that may be associated with unusual physical properties. Habershon, S Cheung, EY Harris, KDM Johnston, RL Powder diffraction indexing as a pattern recognition problem: A new approach for unit cell determination based on an artificial neural network JOURNAL OF PHYSICAL CHEMISTRY A, 108, 2004, 711-716. An artificial neural network, in combination with local optimization, is shown to be an effective approach for determining unit cell parameters directly from powder diffraction data. The viability of this new approach is initially demonstrated using simulated powder diffraction data. Subsequently, the successful application of the method to determine unit cell parameters is illustrated for two materials using experimental powder X-ray diffraction data recorded on a standard laboratory diffractometer. 2003 Neumann, MA X-Cell: a novel indexing algorithm for routine tasks and difficult cases JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 356-365. X-Cell is a novel indexing algorithm that makes explicit use of systematic absences to search for possible indexing solutions from cells with low numbers of calculated reflections to cells with high numbers of reflections. Space groups with the same pattern of systematic absences are grouped together in powder extinction classes, and for a given peak number range an independent search is carried out in each powder extinction class. The method has the advantage that the correct cell is likely to be found before the rapid increase of possible solutions slows down the search significantly. A successive dichotomy approach is used to establish a complete list of all possible indexing solutions. The dichotomy procedure is combined with a search for the zero-point shift of the diffraction pattern, and impurity peaks can be dealt with by allowing for a user-defined portion of unindexed reflections. To rank indexing solutions with varying numbers of unindexed reflections, a new figure of merit is introduced that takes into account the highest level of agreement typically obtained for completely incorrect unit cells. The indexing of long and flat unit cells is facilitated by the possibility to search for rows or zones in reciprocal space first and then to use the lattice parameters of the dominant row or zone in the unit-cell search. The main advantages of X-Cell are robustness and completeness, as demonstrated by a validation study on a variety of compounds. The dominant phase of phase mixtures can be indexed in the presence of up to 50% of impurity peaks if high-quality synchrotron data are available. Coelho, AA Indexing of powder diffraction patterns by iterative use of singular value decomposition JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 86-95 A fast method for indexing powder diffraction patterns has been developed for large and small lattices of all symmetries. The method is relatively insensitive to impurity peaks and missing high d-spacings: on simulated data, little effect in terms of successful indexing has been observed when one in three d-spacings are randomly removed. Comparison with three of the most popular indexing programs, namely ITO, DICVOL91 and TREOR90, has shown that the present method as implemented in the program TOPAS is more successful at indexing simulated data. Also significant is that the present method performs well on typically noisy data with large diffractometer zero errors. Critical to its success, the present method uses singular value decomposition in an iterative manner for solving linear equations relating hkl values to d-spacings. Florence, AJ Baumgartner, B Weston, C Shankland, N Kennedy, AR Shankland, K David, WIF Indexing powder patterns in physical form screening: Instrumentation and data quality JOURNAL OF PHARMACEUTICAL SCIENCES 92, 2003, 1930-1938. Two multisample laboratory powder diffractometers have been evaluated for the purpose of pattern indexing in the context of physical form screening. Both diffractometers utilise foil transmission geometry, primary monochromated radiation, and a position-sensitive detector. Data collected from six compounds (sotalol hydrochloride, hydroflumethiazide, verapamil hydrochloride, captopril, clomipramine hydrochloride, and famotidine) showed good angular resolution (FWHM as small as ca. 0.06degrees) and lattice parameters were easily obtained using the indexing program DICVOL-91. The extent of preferred orientation in each pattern was estimated using the DASH implementation of the March-Dollase function and is most evident with clomipramine hydrochloride and famotidine. Otherwise, the data compare favorably with reference capillary data sets. In conclusion, where there is a requirement to analyze 20-30 samples per day, with an emphasis on obtaining the high-quality data that are important in pattern recognition and imperative in indexing, the combination of foil transmission geometry, primary monochromated radiation, plus a position-sensitive detector is highly effective. The data also afford opportunities for crystal structure determination. Hageman, JA Wehrens, R De Gelder, R Buydens, LMC Powder pattern indexing using the weighted crosscorrelation and genetic algorithms JOURNAL OF COMPUTATIONAL CHEMISTRY 24, 2003, 1043-1051. X-ray diffraction is a powerful technique for investigating the structure of crystals and crystalline powders. Unfortunately, for powders, the first step in the structure elucidation process, retrieving the unit cell parameters (indexing), is still very critical. In the present article, an improved approach to powder pattern indexing is presented. The proposed method matches peak positions from experimental X-ray powder patterns with peak positions from trial cells using a recently published method for pattern comparison (weighted crosscorrelation). Trial cells are optimized with Genetic Algorithms. Patterns are not pretreated to remove any existing zero point shift, as this is determined during optimization. Another improvement is the peak assignment procedure. This assignment is needed for determining the similarity between lines from trial cells and experiment. It no longer allows calculated peaks to be assigned twice to different experimental peaks, which is beneficial for the indexing process. The procedure proves to be robust with respect to false peaks and accidental or systematic absensences of reflections, and is successfully applied to powder patterns originating from orthorhombic, monoclinic, and triclinic compounds measured with synchrotron as well as with conventional laboratory X-ray diffractometers. Powder Pattern Decomposition 2006 Feng, ZJ Dong, C GENEFP: a full-profile fitting program for X-ray powder patterns using the genetic algorithm JOURNAL OF APPLIED CRYSTALLOGRAPHY 39, 2006, 615-617. GENEFP is a full-profile fitting program, employing a fundamental-parameters method, for Cu-target X-ray powder patterns. In this program, the Le Bail method is used to determine integrated intensities and the genetic algorithm is used to search for the proper fundamental parameters. When some parameters, such as the grain size, have large uncertainties, the genetic algorithm has an advantage over conventional least-squares methods in finding the global extremum. Altomare, A Cuocci, C Giacovazzo, C Moliterni, AGG Rizzi, R The combined use of Patterson and Monte Carlo methods for the decomposition of a powder diffraction pattern JOURNAL OF APPLIED CRYSTALLOGRAPHY 39, 2006, 145-150. The success of ab initio crystal structure solution by powder diffraction data is strictly related to the quality of the integrated intensity estimates. A new method that is able to improve the pattern decomposition step has been developed. It combines the inversion of a suitably modified Patterson map with the use of the Hamming codes [13,10] and [40,36] in order to explore more decomposition trials. The new approach has been introduced in EXPO2005, an updated version of EXPO2004, and successfully applied to a set of known organic and inorganic structures. 2005 Altomare, A Cuocci, C da Silva, I Giacovazzo, C Moliterni, AGG Rizzi, R Full powder pattern decomposition and direct phasing in EXPO2004: A statistical study POWDER DIFFRACTION 20, 2005, 327-333. Ab initio crystal structure solution by powder diffraction data is based on the experimental full pattern decomposition process: the resulting structure factor moduli are used for direct phasing. The extracted intensity estimates are scarcely accurate (overlapping, background, and preferred orientation are the main causes of the lack of accuracy), no matter if Le Bail or Pawley method is adopted: consequently the structure solution process is not straightforward. We have focused our attention on the relation between the efficiency of the EXP02004 phasing process and the various parameters which are normally used in the full pattern decomposition process, e.g., the peak shape function, the number of refinement cycles, the degree of overlapping. Different steps of the phasing process are considered: the definition of the unit cell, the determination of the space group, and the application of direct methods. 2004 Altomare, A Caliandro, R Cuocci, C da Silva, I Giacovazzo, C Moliterni, AGG Rizzi, R The use of error-correcting codes for the decomposition of a powder diffraction pattern JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 204-209. The decomposition of a powder diffraction pattern consists of the extraction of the intensities of the individual reflections from the experimental profile. The process is crucial for structure determination from powder diffraction data, but its accuracy is limited by the intrinsic peak overlap. A substantial improvement is achieved by considering clusters of reflections in strong overlap and partitioning in a systematic way the total intensity of each cluster among the constituent reflections. In this paper, error-correcting codes are used to explore the set of decomposition trials obtained by combining the partitions of various clusters of overlapping reflections. Linear ternary codes resulting from modifications of the Hamming codes [ 13, 10] and [ 40, 36] have been considered as the most suited for the present problem. They have been included in the EXPO program via their generator matrices. Tests on a set of experimental powder patterns show that an efficient decomposition procedure consists of performing only 27 decomposition trials, determined as the codewords of an [ndoub, 3] code, where ndoub is the number of doublets of strong overlapping reflections found in the experimental profile. This allows a reduction in the number of trials, thus processing about 2% of the number used in a previous design of the same procedure, leading to a reduction of the total execution time by nearly the same amount. 2003 Guo, LP Cheng, ZX Han, FT Liu, Y Zhao, ZX Simulated annealing method for powder diffraction pattern decomposition ACTA PHYSICA SINICA 52, 2003, 2842-2848. Simulated annealing algorithm was applied in the decomposition of neutron and x-ray powder diffraction pattern. The method described in this paper has two main advantages: first, the pattern decomposition results do not depend on the starting peak parameters, thus the difficulty in the choice of initial solutions, which occurs in fitting a complex pattern composed of severely overlapped peaks by a conventional least-squares profile fitting method, is overcome; secondly, it has the ability of searching for global other than local optimal solutions, thus can effectively resolve the multi-solution problem mathematically, and this advantage is the most useful when decomposing complex patterns with several local optimal solutions. The computing step is described in detail, the setting of relative parameters is discussed, and the simulated annealing method is compared with a conventional least-squares profile fitting method through both simulated pattern and actual pattern to demonstrate its unique advantage in the decomposition, of, complex pattern. In principle, the method can also be applied in other kinds of spectra which can be described by profile shape function. Altomare, A Caliandro, R Cuocci, C Giacovazzo, C Moliterni, AGG Rizzi, R A systematic procedure for the decomposition of a powder diffraction pattern JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 906-913. Ab initio crystal structure solution from powder diffraction data can be attained by means of the two-stage method: first the integrated intensities of individual reflections are extracted from the experimental profile; then the extracted intensities are processed by direct methods to recover their phase. The efficiency of the direct-methods process is strongly affected by the accuracy of the extracted intensities and this is a serious drawback for the solution of organic compounds, where the presence of light atoms leads to a rapid decrease of the scattering at high angles. In order to overcome this problem, a procedure is proposed which generates a set of different intensity partitions for groups of reflections in strong overlap: the resulting decomposition trials are supplied to direct methods. The procedure is able to reduce the phase error at the end of the phasing process by up to 50degrees and enables the solution of organic structures with data resolution not worse than 1.5 Angstrom in a reasonable computing time. The procedure has been implemented in the EXPO program, which makes use of the Le Bail extraction algorithm. Peterson, VK Lattice parameter measurement using Le Bail versus structural (Rietveld) refinement: A caution for complex, low symmetry systems POWDER DIFFRACTION 20, 2005, 14-17. The measurement of lattice parameters using the Le Bail method was shown to be inappropriate for a complex, low symmetry, structure, even with high resolution synchrotron diffraction data. The method failed as a result of ambiguous indexing in the absence of constraints on diffraction intensities, that arise when a structural model is used, combined with the large number of reflections. A caution for the use of the Le Bail and other whole-powder pattern decomposition methods is presented, particularly for high reflection density data. Wright, JP Extraction and use of correlated integrated intensities with powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2005, 791-802. The transformation of a powder diffraction profile into a set of correlated integrated intensities allows crystallographic calculations to be performed without modelling raw diffractometer counts. By carrying out this transformation it is possible to preserve the information about peak overlap without needing to retain the multitude of experimental details and description of the peak shape function. An implementation is described which allows problems of significant size to be tackled. Least squares refinement. issues of data quality and the generation and importance of free R-factors are discussed. Ma, HW Liang, JK Liu, GY Rao, GH UACIEM: A new method to extract reliable intensities of nonequivalent systematical overlapping reflections from powder diffraction data POWDER DIFFRACTION 19, 2004, 333-339. A new method, namely UACIEM, to extract reliable intensities of nonequivalent systematical overlapping reflections has been proposed and tested by simulated powder diffraction data from known crystal structures. Using both crystallographic and structural chemistry information, the method reconstructs diffraction intensities and solves a crystal structure through an iterative procedure. Our study shows that UACIEM is successful for cases where more than 30% of the total scattering power is located with precision from equivalent systematical overlapping reflections. The UACIEM process is not needed when equivalent systematical overlapping reflections are sufficient to reveal a crystal structure. UACIEM may fail in cases when: (i) only a small portion of the total scattering power (e.g., less than 7%) can be located, and (ii) most of the total scattering power (e.g., 95%) is located, but the atomic coordinates are not accurately known. The UACIEM method is superior to the simple equipartition methods for nonequivalent systematical overlapping reflections. Ma, HW Liang, JK A new approach to extract reliable intensities of non-equivalent systematical overlapping reflections from powder diffraction data ACTA PHYSICA SINICA 53, 2004, 829-834. A new approach to extract reliable intensities from systematical non-equivalent overlapping reflections has been proposed and tested by simulated powder diffraction pattern of known structures. By using both crystallographic and structural chemistry knowledge, the IDM-UAIC reconstructs the intensities and solves the structure through an iterative procedure. The results show that IDM-UAIC succeeds when more than 30% of the total scattering power can be located in a reasonable precise from the equivalent systematical overlapping reflections. The IDM-UAIC procedure is superior to the simple equi-partition methods for the nonequivalent systematical overlapping reflections while it is equivalent to simple equi-partition methods for the equivalent systematical overlapping reflections. Tucker, MG Dove, MT Keen, DA Application of the reverse Monte Carlo method to crystalline materials JOURNAL OF APPLIED CRYSTALLOGRAPHY 34, 2001, 630-638. An implementation of the reverse Monte Carlo (RMC) method for the study of crystalline materials from polycrystalline neutron total scattering data is presented. The new feature is that explicit account is taken of the intensities of Bragg peaks, which are extracted from the data using the Pawley method. The use of Bragg peaks ensures that the RMC models reproduce both the long-range and the short-range order reflected in the experimental data. The relative effects of different contributions to the data sets in the RMC method are assessed and successful applications are illustrated using the quartz and cristobalite polymorphs of silica as examples. Space group determination Altomare, A Caliandro, R Camalli, M Cuocci, C da Silva, I Giacovazzo, C Moliterni, AGG Spagna, R Space-group determination from powder diffraction data: a probabilistic approach JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 957-966. Experimental powder diffraction diagrams, once indexed and decomposed into single diffraction intensities, can be submitted to statistical analysis for the determination of space-group symmetry. A new algorithm is illustrated, which is able to provide, on a quantitative basis, a probability value for each extinction symbol compatible with the previously established lattice symmetry. The algorithm has been implemented in EXPO2004 [Altomare, Caliandro, Camalli, Cuocci, Giacovazzo, Moliterni & Rizzi ( 2004). J. Appl. Cryst. 37, 1025 - 1028] and has been successfully tested using a large set of experimental data. Markvardsen, AJ David, WIF Johnson, JC Shankland, K A probabilistic approach to space-group determination from powder diffraction data ACTA CRYSTALLOGRAPHICA SECTION A 57, 2001, 47-54. An algorithm for the determination of the space-group symmetry of a crystal from powder diffraction data, based upon probability theory, is described. Specifically, the relative probabilities of different extinction symbols are assessed within a particular crystal system. In general, only a small number of extinction symbols are relatively highly probable and a single extinction symbol is often significantly more probable than any other. Several examples are presented to illustrate this approach. Structure solution 2006 Burla, MC Caliandro, R Carrozzini, B Cascarano, GL De Caro, L Giacovazzo, C Polidori, G Siliqi, D The revenge of the Patterson methods. I. Protein ab initio phasing JOURNAL OF APPLIED CRYSTALLOGRAPHY 39, 2006, 527-535. Direct methods combined with direct-space refinement procedures are the standard tools for ab initio crystal structure solution of macromolecules via diffraction data collected up to atomic or quasi-atomic resolution. An entirely direct-space approach is described here: it includes an automated Patterson deconvolution method, based on the minimum superposition function, followed by an effective direct-space refinement, consisting of cycles of electron density modification. The new approach has been implemented in a new version of the SIR2004 program and tested on a large set of test structures selected from the Protein Data Bank, with data resolution better than 1.6 angstrom and number of non-hydrogen atoms in the asymmetric unit up to 2000. The new procedure proved to be extremely efficient and very fast in solving crystal structures with atomic resolution data and heavy atoms: their solution and refinement requires a computing time roughly comparable with that necessary for solving small-molecule crystal structures via a modern computer program. It markedly overcomes direct methods, even for crystal structures with atomic data resolution and heaviest atomic species up to calcium, as well as for crystal structures with quasi-atomic data resolution (i.e. 1.2 - 1.6 angstrom). The Patterson approach proved to be loosely dependent on the structure complexity. Chong, SY Tremayne, M Combined optimization using cultural and differential evolution: application to crystal structure solution from powder diffraction data CHEMICAL COMMUNICATIONS iss 39, 2006, 4078-4080. The principles of social and biological evolution have been combined in a Cultural Differential Evolution hybrid global optimization technique and applied to crystal structure solution. David, WIF Shankland, K van de Streek, J Pidcock, E Motherwell, WDS Cole, JC DASH: a program for crystal structure determination from powder diffraction data JOURNAL OF APPLIED CRYSTALLOGRAPHY 39, 2006, 910-915. DASH is a user-friendly graphical-user-interface-driven computer program for solving crystal structures from X-ray powder diffraction data, optimized for molecular structures. Algorithms for multiple peak fitting, unit-cell indexing and space-group determination are included as part of the program. Molecular models can be read in a number of formats and automatically converted to Z-matrices in which flexible torsion angles are automatically identified. Simulated annealing is used to search for the global minimum in the space that describes the agreement between observed and calculated structure factors. The simulated annealing process is very fast, which in part is due to the use of correlated integrated intensities rather than the full powder pattern. Automatic minimization of the structures obtained by simulated annealing and automatic overlay of solutions assist in assessing the reproducibility of the best solution, and therefore in determining the likelihood that the global minimum has been obtained. Altomare, A Cuocci, C Giacovazzo, C Moliterni, AGG Rizzi, R Powder diffraction: the new automatic least-squares Fourier recycling procedure in EXPO2005 JOURNAL OF APPLIED CRYSTALLOGRAPHY 39, 2006, 558-562. The Rietveld method is the most widely used approach for refining crystal structures from powder diffraction patterns. It requires sufficiently accurate structure models and user skill. A method is described which is often able to complete and refine a structure model by using an automatic least-squares procedure applicable to reflection integrated intensities. A weighting scheme has been devised that is capable of taking into account the lower accuracy of the estimates of the overlapping reflections. Charge flipping Wu, JS Leinenweber, K Spence, JCH O'Keeffe, M Ab initio phasing of X-ray powder diffraction patterns by charge flipping NATURE MATERIALS 5, 2006, 647-652. Determining crystal structures from powder X- ray diffraction data remains a challenging problem in materials science. By embedding a Le-Bail-like procedure within the recently discovered charge-flipping phasing algorithm, an extremely simple, fast and effective ab initio method has been developed to determine phases directly from indexed powder diffraction patterns. The algorithm solves the degeneracy problem by applying spherical averaging for overlapping Bragg reflections, while solving the phase problem by using the Oszlanyi-Suto charge-flipping algorithm. The processes of peak decomposition and phasing are integrated within the same iteration, and a dynamic support is used. The Fienup hybrid input-output algorithm is also incorporated to minimize stagnation. The ability of the algorithm to find structure-factor phases rapidly is found to assist with the fundamental problem of degeneracy ( overlapping reflections) which is intrinsic to powder diffraction data. Space-group and chemical-composition information are not needed as inputs, and can be determined from the result. The method is illustrated using several experimental powder patterns of indifferent quality. Palatinus, L Ab initio determination of incommensurately modulated structures by charge flipping in superspace ACTA CRYSTALLOGRAPHICA SECTION A 60, 2004, 604-610. The charge flipping algorithm proposed by Oszlanyi & Suto [Acta Cryst. (2004), A60, 134-141] for ab initio reconstruction of crystal structures is generalized towards superspace. Its efficiency is demonstrated by successful reconstruction of eight known incommensurately modulated structures from experimental data. The output of the charge flipping algorithm is an electron density with symmetry P1. The symmetry of the structure is recovered by locating the positions of symmetry operators and averaging the density over the symmetry-related pixels. The reconstruction of a modulated structure by the charge flipping algorithm and the accuracy of the result is demonstrated in detail on the modulated structure of tetraphenylphosphonium hexabromotellurate(IV) bis{dibromoselenate(I)}. 2005 Markvardsen, AJ Shankland, K David, WIF Didlick, G Characterization of a hybrid Monte Carlo search algorithm for structure determination JOURNAL OF APPLIED CRYSTALLOGRAPHY 38, 2005, 107-111. A hybrid Monte Carlo (HMC) search algorithm has recently been shown to be a promising method for structure determination from powder diffraction data [ Johnston, David, Markvardsen & Shankland ( 2002). Acta Cryst. A58, 441 - 447]. Here, the performance of the algorithm on a number of different crystal structures is investigated as a function of its control parameters. This detailed analysis required the use of a system for distributed computing in order to keep the calculation times within a reasonable time frame. The results obtained confirm previous findings and a detailed discussion of the effect of the control parameters on the efficiency of the HMC method is provided. The results suggest a method for setting these parameters automatically, which is an essential step if HMC is to find routine use in the determination of crystal structures. Rius, J Advances and some recent applications of the origin-free modulus sum function ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2005, 826-832. Since its discovery, the direct methods origin-free modulus sum function [Rius, J., Acta Cryst A49 (1993) 406-409] has been responsible for the solution of a number of difficult crystal structures of minerals and other inorganic compounds from powder diffraction data. This is principally due to the efficiency, robustness and simplicity of implementation of this phase refinement function. The first part of the contribution describes some recent examples on the application of the origin-free modulus sum function to complex structures. In the second part, a powerful variant of this function is introduced which discriminates even better the correct solutions from the wrong ones. This is illustrated with its application to single-crystal data of three selected organic structures. One of these test structures contains 317-atom molecules and is regarded as one of the most difficult structures to be solved with reciprocal space direct methods. This variant could also be useful for those phase refinement strategies based on alternating reciprocal- and real-space procedures, provided that the weak reflections are known. Cerny, R Favre-Nicolin, V FOX: A friendly tool to solve nonmolecular structures from powder diffraction POWDER DIFFRACTION 20, 2005, 359-365. Structural characterization from powder diffraction of compounds not containing isolated molecules but three-dimensional infinite structure (alloys, intermetallics, framework compounds, extended solids) by direct space methods has been largely improved in the last 15 years. The success of the method depends very much on a proper modeling of the structure from building blocks. The modeling from larger building blocks improves the convergence of the global optimization algorithm by a factor of up to 10. However, care must be taken about the correctness of the building block, like its rigidity, deformation, bonding distances, and ligand identity. Dynamical occupancy correction implemented in the direct space program FOX has shown to be useful when merging excess atoms, and even larger building blocks like coordination polyhedra. It also allows joining smaller blocks into larger ones in the case when the connectivity was not a priori evident from the structural model. We will show in several examples of nonmolecular structures the effect of the modeling by correct structural units. Brodski, V Peschar, R Schenk, H Organa - a program package for structure determination from powder diffraction data by direct-space methods JOURNAL OF APPLIED CRYSTALLOGRAPHY 38, 2005, 688-693. A new software package has been developed, named Organa, for ab initio solution of crystal structures from powder diffraction data by direct-space methods. The package contains energy-guiding Monte Carlo and grid-search algorithms and is based on a combined global minimization of the R factor and a potential energy function of the system with the option of local minimization of the cost function for each generated trial structure. Basically, the potential energy function consists of van der Waals interactions, but harmonic potentials can be added to impose soft distance restraints. The program was successfully applied to the structure determination of a series of melamine phosphate compounds. The program is freely available ( for all Windows platforms) from the correspondence author upon request. Caliandro, R Carrozzini, B Cascarano, GL De Caro, L Giacovazzo, C Siliqi, D Phasing at resolution higher than the experimental resolution ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY 61, 2005, 556-565. Limited experimental resolution is a unavoidable feature in macromolecular crystallography: it may hinder or make difficult the determination of the crystal structure. A novel procedure is presented which from an approximate electron-density map extrapolates the moduli and phases of non-measured reflections beyond and behind the experimental resolution limit. Applications to a set of test structures show that the extrapolation can be successfully accomplished. As a consequence, the phase estimates of the observed reflections are subsequently improved and the interpretability of the corresponding electron-density map increases. The use of the extrapolated values for the non-measured reflections provides additional information for the map, which shows a resolution higher than the experimental resolution. Rius-Palleiro, J Peral, I Margiolaki, I Torrelles, X Solving centrosymmetrical zeolites from powder diffraction data by combining the direct-methods origin-free modulus sum function with the isomorphous replacement technique. X JOURNAL OF APPLIED CRYSTALLOGRAPHY 38, 2005, 906-911. A new two-stage strategy for the solution of zeolite crystal structures with centrosymmetrical frameworks is proposed; this strategy exploits the information contained in multiple powder diffraction patterns. In the first stage, the structure-directing agent (SDA), i.e. the template molecule, is located by combining the isomorphous replacement technique with direct methods. In the second stage, the framework atoms are found by applying direct methods strengthened with additional information coming from the located SDA. All phase refinements are based on the maximization of the origin-free modulus sum function as implemented in the direct-methods program XLENS [Rius (2004). Z. Kristallogr. 219, 826-832], with data resolution limits equal to 3.2 angstrom for the first and 2.21 angstrom for the second stage. The viability of this new two-stage strategy is illustrated with the solution of the novel zeolite ITQ-32, containing nine Si atoms in the asymmetric unit, from synchrotron powder diffraction data. Especially important is the confirmation that the intensity differences involved in the SDA isomorphous replacement are significantly greater than the experimentally measured errors. 2004 Altomare, A Caliandro, R Camalli, M Cuocci, C Giacovazzo, C Moliterni, AGG Rizzi, R Spagna, R Gonzalez-Platas, J Towards EXPO2005 ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 833-837 New procedures have been introduced in EXPO2004 (Altomare. A.. Caliandro, R., Camalli, M., Cuocci, C., da Silva, I., Giacovazzo, C., Moliterni, A. G. G. & Rizzi, R., J. Appl. Cryst. Submitted) aiming at making the solution process more straightforward, particularly for cases very resistant to the ab-initio approach. Altomare, A Caliandro, R Camalli, M Cuocci, C Giacovazzo, C Moliterni, AGG Rizzi, R Automatic structure determination from powder data with EXPO2004 JOURNAL OF APPLIED CRYSTALLOGRAPHY37, 2004, 1025-1028 EXPO2004 is the updated version of the EXPO program [Altomare et al. (1999). J. Appl. Cryst. 32, 339 - 340]. The traditional steps of the ab initio powder solution process are performed automatically: indexing, space-group determination, decomposition of the pattern for extracting the observed structure-factor moduli, structure solution by direct methods, model refinement by Rietveld technique. Special strategies may be applied to improve both the estimates of the extracted structure-factor moduli and the quality of the structure model. In addition, the use of special procedures exploiting available supplementary information on molecular geometry can be successfully adopted. The graphical interface has also been improved. Altomare, A Giacovazzo, C Grazia, A Moliterni, G Rizzi, R Direct methods optimised for solving crystal structure by powder diffraction data: Limits, strategies, and prospects JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 109, 2004, 125-132. ab-initio crystal structure solution by powder diffraction data requires great efforts because of the collapse of the experimental information onto the one dimensional 2theta axis of the pattern. Different strategies will be described aiming at improving the process of extraction of the integrated intensities from the experimental pattern in order to make more straightforward the structure solution process by direct methods. Particular attention will be devoted to the EXPO program. Some of its performance will be analysed and results will be shown. Altomare, A Cuocci, C Giacovazzo, C Grazia, A Moliterni, G Rizzi, R Completion of crystal structure with polyhedral coordination: A new procedure EUROPEAN POWDER DIFFRACTION EPDIC 8 - MATERIALS SCIENCE FORUM 443-4, 2004, 23-26. The ab-initio crystal structure solution via powder diffraction data is often uncomplete. A recent procedure POLPO [1] aims at completing a partial structure model provided by Direct Methods by exploiting the prior information on the polyhedral coordination of the located atoms (tetrahedral or octahedral) and their connectivity has been developed. The POLPO procedure requires that all the cations are correctly labelled and rightly located. This condition does not always occur, particularly when the data quality is poor. A new method is described which is able to locate missing cations and surrounding anions when the cation coordination is tetrahedral or octahedral. Favre-Nicolin, V Cerny, R FOX, 'free objects for crystallography': a modular approach to ab initio structure determination from powder diffraction JOURNAL OF APPLIED CRYSTALLOGRAPHY 35, 2002, 734-743. A new program has been developed for ab initio crystal structure determination from powder diffraction data (X-ray and neutron). It uses global-optimization algorithms to solve the structure by performing trials in direct space. It is a modular program, capable of using several criteria for evaluating each trial configuration (e.g. multi-pattern). It is also modular in the description of the crystal content, with the possibility of describing building blocks in the sample, such as polyhedra or molecules, and with automatic adaptive handling of special positions and sharing of identical atoms between neighbouring building blocks. It can therefore find the correct structure without any assumption about the connectivity of the building blocks and is suitable for any kind of material. Several optimization algorithms (simulated annealing, parallel tempering) are available, with the possibility of choosing the convergence criterion as a combination of available cost functions. This program is freely available for Linux and Windows platforms; it is also fully 'open source', which, combined with an object-oriented design and a complete developer documentation, ensures its future evolution. Favre-Nicolin-, V Cerny, R A better FOX: using flexible modelling and maximum likelihood to improve direct-space ab initio structure determination from powder diffraction ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 847-856. Ab initio structure determination using direct-space methods, although relying on an essentially bruteforce approach, can be greatly improved through smarter algorithms. The most basic improvement involves the use C, of prior information to reduce the number of configurations evaluated to find the structure solution. It is however vitally important that the parametrization used to incorporate this prior information does not reduce the efficiency with which the configuration space is explored. We will show that this can be achieved by defining molecules and polyhedra through a set of restraints associated to dedicated random changes. allowing to solve structures up to three times as fast as with the 'standard' approach where atomic positions are parametrized directly from bond lengths, bond angles and dihedral angles. To further enhance the efficiency of the algorithm, it is also possible to 'tune' the convergence criterion used to compare the structural model to the observed diffraction data (usually chi(2) or R-wp). By using Maximum Likelihood principles. it is shown that incorporating the fact that the model is approximate in the chi(2) evaluation can improve the algorithm convergence towards the structure solution. Favre-Nicolin, V Cerny, R FOX: Modular approach to crystal structure determination from powder diffraction EUROPEAN POWDER DIFFRACTION EPDIC 8 MATERIALS SCIENCE FORUM 443-4, 2004, 35-38. Program FOX for ab initio crystal structure determination from powder diffraction uses global optimization algorithms to find the correct structure by making trials in the direct space. It is a modular program, capable of using several criteria for evaluating each trial configuration, e.g. combining neutron and X-ray diffraction patterns. The program describes the structural building blocks (polyhedrons, molecules etc.) with their internal coordinates (Z-matrices), thus all, owing natural constraints on interatomic distances and angles. Identical atoms shared between neighboring building blocks, and special positions are handled with an automatic, adaptive method (Dynamical Occupancy Correction). Several algorithms (Simulated Annealing, Parallel Tempering) are currently available. The program is based on an object-oriented crystallographic library ObjCryst++ (programming language c++). The program and the library are available for Linux and Windows on http://objcryst.sourceforge.net. Inorganic and organic structures with the complexity up to 26 independents atoms are routinely solved from laboratory X-ray, synchrotron or neutron data. Harris, KDM Habershon, S Cheung, EY Johnston, RL Developments in genetic algorithm techniques for structure solution from powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 838-846. DE X-ray powder diffraction; structure analysis; structure solution; genetic algorithm; molecular crystals ID CRYSTAL-STRUCTURE DETERMINATION; X-RAY-DIFFRACTION; MONTE-CARLO APPROACH; R-FACTOR; ACID; ENERGY; SYSTEM; UNIT AB This paper presents an overview of developments that have taken place in recent years in the genetic algorithm technique for structure solution from powder diffraction data. After a brief resume of the essential features of the genetic algorithm technique for structure solution, the paper highlights recent developments in fundamental aspects of the technique, including the development of parallel computing concepts, the analysis of the evolutionary history in genetic algorithm structure solution calculations and the combination of energy information together with the powder diffraction data in structure solution. Several examples are also given to illustrate the application of the genetic algorithm technique to solve crystal structures of different types of organic molecular materials, including oligopeptides and multi-component co-crystals. Altomare, A Caliandro, R Giacovazzo, C Moliterni, AGG Rizzi, R Solution of organic crystal structures from powder diffraction by combining simulated annealing and direct methods JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 230-238. The ab initio crystal structure solution from powder diffraction data can be attempted via direct methods. If heavy atoms are present, they are usually correctly located; then some crystal chemical information can be exploited to complete the partial structure model. Organic structures are more resistant to direct methods; as an alternative, their molecular geometry is used as prior information for Monte Carlo methods. In this paper, a new procedure is described which combines the information contained in the electron density map provided by direct methods with a Monte Carlo method which uses simulated annealing as a minimization algorithm. A figure of merit has been designed based on the agreement between the experimental and calculated profiles, and on the positions of the peaks in the electron density map. The procedure is completely automatic and has been included in EXPO; its performance has been validated and tested for a set of known molecular structures. Habershon, S Harris, KDM Johnston, RL Development of a multipopulation parallel genetic algorithm for structure solution from powder diffraction data JOURNAL OF COMPUTATIONAL CHEMISTRY 24, 2003, 1766-1774. Previously, the genetic algorithm (GA) approach for direct-space crystal structure solution from powder diffraction data has been applied successfully in the structure determination of a range of organic molecular materials. In this article, we present a further development of our approach, namely a multipopulation parallel GA (PGA), which is shown to give rise to increased speed, efficiency, and reliability of structure solution calculations, as well as providing new opportunities for further optimizing our GA methodology. The multipopulation PGA is based on the independent evolution of different subpopulations, with occasional interaction (e.g., transfer of structures) allowed to occur between the different subpopulations. Different strategies for carrying out this interpopulation communication are considered in this article, and comparisons are made to the conventional single-population GA. The increased power offered by the PGA approach creates the opportunity for structure determination of molecular crystals of increasing complexity. Brodski, V Peschar, R Schenk, H A Monte Carlo approach to crystal structure determination from powder diffraction data JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 239-243. A new direct-space method for ab initio solution of crystal structures from powder diffraction data is presented. The approach consists of a combined global minimization of R-wp and the potential energy of the system. This method was tested on two organic compounds with known structure and also applied successfully in the structure determination of the previously unknown structure of melamine pyrophosphate. 2002 Giacovazzo, C Altomare, A Cuocci, C Moliterni, AGG Rizzi, R Completion of crystal structure by powder diffraction data: a new method for locating atoms with polyhedral coordination JOURNAL OF APPLIED CRYSTALLOGRAPHY 35, 2002, 422-429. Ab initio crystal structure solution via powder diffraction data is often incomplete: frequently, the heavy atoms are correctly located but the light-atom positions are usually unreliable. The recently developed procedure POLPO [Altomare et al. (2000). J. Appl. Cryst. 33, 1305-1310], implemented in the EXPO program [Altomare et al. (1999). J. Appl. Cryst. 32, 339-340], aims at completing a partial structure model provided by direct methods by exploiting the prior information on the polyhedral coordination of the located atoms (tetrahedral or octahedral) and their connectivity. The POLPO procedure requires that all the cations are correctly labelled and rightly located. This condition does not always occur, particularly when the data quality is poor. A new method is described which is able to locate missing cations and surrounding anions when the cation coordination is tetrahedral or octahedral. The procedure has been successfully checked on different test structures. Altomare, A Cuocci, C Giacovazzo, C Guagliardi, A Moliterni, AGG Rizzi, R Real-space technique applied to crystal structure determination from powder data JOURNAL OF APPLIED CRYSTALLOGRAPHY 35, 2002, 182-184. Real-space techniques used for phase extension and refinement in the modern direct procedures for ab initio crystal structure solution of proteins have been optimized for application to powder diffraction data. The new process has been implemented in a modified version of EXPO [Altomare et al. (1999). J. Appl. Cryst. 32, 339-340]. The method is able to supply a structural model that is more complete than that provided by the standard EXPO program. The model is then refined via a diagonal least-squares procedure, but only when the ratio of the number of observations to the number of structure parameters to be refined is larger than a given threshold. Altomare, A Giacovazzo, C Ianigro, M Moliterni, AGG Rizzi, R Peak labelling in electron density maps from powder data: the use of crystal chemical information JOURNAL OF APPLIED CRYSTALLOGRAPHY 35, 2002, 21-27. Direct methods applied to powder diffraction data often provide electron density maps of which the quality is usually affected by systematic and/or random phase errors, by amplitude truncation effects in the series representation of the electron density, etc. The frequent incorrect labelling of the peaks can strongly affect the efficiency of the procedures used for crystal structure refinement. For example, the success of alternative techniques, such as POLPO [Altomare et al. (2000). J. Appl. Cryst. 33, 1305-1310], requires that all the heavy atoms be positioned and exactly labelled. Johnston, JC David, WIF Markvardsen, AJ Shankland, K A hybrid Monte Carlo method for crystal structure determination from powder diffraction data ACTA CRYSTALLOGRAPHICA SECTION A 58, 2002, 441-447. A hybrid Monte Carlo algorithm for crystal structure determination from powder diffraction data is presented. The algorithm combines the key components of molecular dynamics and Monte Carlo simulations to achieve efficient sampling of phase space, allowing the crystal structure of capsaicin to be determined from powder diffraction data more effectively than by a simulated-annealing approach. The implementation of the algorithm, the choice of the simulation parameters and the performance of the algorithm are discussed. Markvardsen, AJ David, WIF Shankland, K A maximum-likelihood method for global-optimization-based structure determination from powder diffraction data ACTA CRYSTALLOGRAPHICA SECTION A 58, 2002, 316-326. A maximum-likelihood algorithm has been incorporated into a crystal structure determination from a powder diffraction data framework that uses an integrated-intensity-based global optimization technique. The algorithm is appropriate when the structural model being optimized is not a complete description of the crystal structure under study. Nakamura, H Yamazaki, S Ohnishi, T Ida, T Toraya, H The Monte Carlo method for finding missing atoms in solving crystal structures from powder diffraction data without applying a rigid-body approximation POWDER DIFFRACTION 16, 2001, 65-70. The Monte Carlo method is applied to finding missing atoms in solving inorganic crystal structures without applying a rigid-body approximation. Whole powder patterns of alpha -SiO2 and Mg2SiO4 were used for testing a procedure. Four atoms among the six in the asymmetric unit of Mg2SiO4 could be found in the present analysis. The use of well-refined profile parameters enhanced the frequency of correct structure configurations in the Monte Carlo search. Utilizing structural information available for constructing a trial configuration is also considered to be important for efficiently searching the structure solution. A procedure for assignment of equivalent positions to respective atoms is presented. The method can be used as a powerful tool for finding missing atoms in a partially solved structure. A histogram of weighted reliability index in Monte Carlo calculations is very informative for evaluating the performance of the method. (C) 2001 International Centre for Diffraction Data. Review paper 2006 Cheung, EY Harris, KDM Molecular crystal structures from powder X-ray diffraction techniques ZEITSCHRIFT FUR KRISTALLOGRAPHIE Suppl 23, part 1, 2005, 15-20. This paper presents an overview of the genetic algorithm technique for structure solution from powder diffraction data, and gives a number of examples that illustrate the application of this technique to solve crystal structures of different types of molecular solids, including oligopeptides and multi-component co-crystals. Cerny, R Crystal structure of non-molecular compounds from powder diffraction CROATICA CHEMICA ACTA 79, 2006, 319-326. Methods of structure determination from powder diffraction of non-molecular compounds (inorganics, extended solids, intermetallic compounds, etc.) are reviewed. They work either in reciprocal space or in direct space. Those working in reciprocal space use algorithms known from single crystal works (direct methods and Patterson synthesis) and need decomposition of powder patterns to individual reflections. Those working in direct space need no powder pattern decomposition and are based on global optimization of a structural model to improve agreement between the observed and calculated diffraction patterns. The available computer programs working in direct space are summarized. 2005 Le Bail, A Whole powder pattern decomposition methods and applications: A retrospection POWDER DIFFRACTION 20, 2005, 316-326. Methods extracting fast all the peak intensities from a complete powder diffraction pattern are reviewed. The genesis of the modern whole powder pattern decomposition methods (the so-called Pawley and Le Bail methods) is detailed and their importance and domains of application are decoded from the most cited papers citing them. It is concluded that these methods represented a decisive step toward the possibility to solve more easily, if not routinely, a structure solely from a powder sample. The review enlightens the contributions from the Louer's group during the rising years 1987-1993. (C) 2005 International Centre for Diffraction Data. Masciocchi, N Galli, S Sironi, A X-ray powder diffraction characterization of polymeric metal diazolates COMMENTS ON INORGANIC CHEMISTRY 26, 2005, 1-37. Polymeric metal diazolates typically appear as insoluble and intractable powders, the structure of which could only be retrieved by the extensive use of ab-initio X-ray powder diffraction (XRPD) methods from conventional laboratory data. A number of selected examples from the metal pyrazolate, imidazolate, pyrimidin-2-olate and pyrimidin-4-olate classes are presented, highlighting the specific crystallochemical properties, material functionality and methodological aspects of the structure determination process. Christensen, AN Solution of heavy atom structures from powder diffraction data using direct methods. A review of structures solved at Aarhus University POWDER DIFFRACTION 19, 2005, 362-366. Heavy atoms dominate the X-ray scattering from many inorganic compounds like oxides and oxalates, and often only partial structures of these compounds can be obtained by X-ray powder diffraction data. Combining information from X-ray and neutron diffraction data is an advantage. Scattering contributions from the atoms are more evenly distributed in neutron diffraction data than in X-ray diffraction data. Neutron diffraction data can then be used to complete a structure partially solved with data from an X-ray diffraction pattern. Examples of heavy atom structures solved in the time period 1983-2004 using direct methods outlined above are presented. (C) 2004 International Centre for Diffraction Data. Skakle, J Applications of X-ray powder diffraction in materials chemistry CHEMICAL RECORD 5, 2005, 252-262. X-ray powder diffraction is a standard technique in materials chemistry, yet it is often still used in the laboratory as a "one-hit" technique, e.g. for fingerprinting and following the progress of reactions. It is important, however, that the wealth of information available from powder data is not overlooked. While it is only possible here to scratch the surface of possibilities, a range of examples from our research is used to emphasize some of the more accessible techniques and to highlight successes as well as potential problems. The first example is the study of solid solution formation in the oxide systems Ba3-3xLa2xV2O8 and Sr4-xBaxMn3O10 and in the silicate-hydroxyapatite bioceramic, Ca-10(PO4)(6-x)(SiO4)(x)(OH)(2-x). Database mining is also explored, using three phases within the pseudobinary phase diagram Li3SbO4-CuO as examples. All three phases presented different challenges: the structure of Li3SbO4 had been previously reported in higher symmetry than was actually the case, Li3Cu2SbO6 was found to be isostructural with Li2TiO3 but the cation ordering had to be rationalized, and Li3CuSbO5 was believed to be triclinic, presenting challenges in indexing the powder pattern. Quantitative phase analysis is briefly discussed, with the emphasis both on success (determination of amorphous phase content in a novel cadmium arsenate phase) and on possible failure (compositional analysis in bone mineral); the reasons for the problems in the latter are also explored. Finally, the use of an area detector system has been shown to be of value in the study of orientational effects (or lack of them) in non- and partially-ordered biomaterials, including p-HEMA, annulus fibrosis of lumbar discs, and keratin in the horn of cow's hooves. 2004 Baerlocher, C McCusker, L Structure determination from powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 782. Shankland, K Markvardsen, AJ David, WIF Powder diffraction based structural studies of pharmaceuticals ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 857-865. Recent methodological and algorithmic developments in the field of structure determination of materials of pharmaceutical interest from powder diffraction data are discussed. Habershon, S Albesa-Jove, D Cheung, EY Turner, GW Johnston, RL Harris, KDM Fundamental developments in direct-space techniques for structure solution from powder diffraction data EUROPEAN POWDER DIFFRACTION EPDIC 8 MATERIALS SCIENCE FORUM 443-4, 2004, 11-21. Solids that can be prepared only as microcrystal line powders are not suitable for structural investigation using single crystal diffraction techniques, and it is necessary instead to carry out structure determination using powder diffraction data. In this paper, we focus on a direct-space strategy for solving crystal structures directly from powder diffraction data in which a hypersurface based on the powder profile R-factor R-wp is searched using a Genetic Algorithm, and we highlight some recent fundamental developments relating to this methodology. Brandel, V Dacheux, N Chemistry of tetravalent actinide phosphates - Part II JOURNAL OF SOLID STATE CHEMISTRY 177, 2004, 4755-4767. The chemistry and crystal structure of tetravalent cation phosphates, including that of actinides was reviewed several times until 1985. Later, new compounds were synthesized and characterized. In more recent studies it was found that some of previously reported phases, especially those of thorium, uranium, and neptunium, were wrongly identified. In the light of these new facts, an update review and classification of tetravalent actinides phosphates is proposed in this two-part paper. Their crystal structure and some chemical properties are compared to non-actinide cation phosphates. Bergmann, J Le Bail, A Shirley, R Zlokazov, V Renewed interest in powder diffraction data indexing ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 783-790. Recently released powder indexing programs are reviewed and placed in competition with the established programs (ITO, TREOR, DICVOL, etc.) through a series of problems selected among previously unindexed ICDD entries designated as "high quality". Benchmarks are provided for testing indexing programs, based on the bethanechol chloride powder diffraction data. Applying these benchmarks leads to a classification (with respect to this specific example) of indexing programs as they face progressively more difficult situations. High data quality and the user experience to obtain it are concluded to remain the best way to indexing success, given that nearly all programs produce excellent results with excellent data. Lack of attention to data quality, even if followed by use of the most efficient programs, will usually lead to failure. It is demonstrated how not restricting oneself to a single indexing program can considerably increase the chances of success. Burton, AW Structure solution of zeolites from powder diffraction data ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 866-880. This article reviews methods in structure determination of zeolites from powder diffraction data. First, examples of different model building techniques are discussed. Then the applications and limitations of conventional direct methods in zeolite structure solution are examined. Methods for partitioning overlapping peak intensities are also discussed, and examples are given to illustrate improvements in structure elucidation when these techniques are applied. Ab initio structure determination of zeolites from powder data has made great progress within the past 10 years. In particular, the developments of the ZEFSAII, FOCUS, and XLENS algorithms have allowed rapid structure solutions of zeolites, in some cases a few days after their initial discoveries. Harris, KDM Johnston, RL Habershon, S Applications of evolutionary computation in structure determination from diffraction data APPLICATIONS OF EVOLUTIONARY COMPUTATION IN CHEMISTRY 110, 2004, 55-94. Evolutionary algorithms are finding increasing use in the study of a wide range of different types of diffraction data. In this chapter, we review recent applications of evolutionary algorithms to study a variety of structural problems. Examples range from the study of disordered materials by analysis of diffuse scattering data to molecular replacement techniques in biological crystallography. However, the main focus of this chapter is on the application of genetic algorithms in the determination of crystal structures directly from powder diffraction data. The principles underlying the application of genetic algorithm techniques in structure determination from powder diffraction data are described, and applications of this methodology to determine molecular crystal structures of considerable complexity are also highlighted. Clearly the opportunity to determine crystal structures directly from powder diffraction data provides a vital alternative to single-crystal X-ray diffraction, when single crystals of appropriate size and quality for single-crystal diffraction cannot be prepared for the material of interest. Bataille, T Audebrand, N Boultif, A Louer, D Structure determination of thermal decomposition products from laboratory X-ray powder diffraction ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 881-891. Ab initio structure determination from powder diffraction data of compounds resulting from solid state transformations is still rather limited. Two major factors influence the stages of the structure elucidation of these solids, i.e. the lower precision in peak position for indexing and the strong line overlap for extracting integrated intensities. The present study deals with the consideration of these two problems for solving the crystal structure of two thermal-decomposition inorganic products, Nd(NO3)(3) (.) 4 H2O and Pb3O2(NO3)(2). The new features of DICVOL04, as zero shift refinement. a priori zero search and tolerance of spurious lines have been used for indexing, several phases obtained during the thermal treatment of neodymium nitrate hexahydrate. The crystal structures of Nd(NO3)(3) (.) 4 H2O and Pb3O2(NO3)(2) have been solved with the direct methods and the structure model of Pb3O(2)(NO3)(2) has been completed using a global optimisation approach. The monoclinic structure of neodymium nitrate tetrahydrate [a - 10.1744(4) Angstrom, b = 8.9716(5) Angstrom, c = 11.7295(5) Angstrom, beta = 97.384(4)degrees, V = 1061.80 Angstrom(3), S.G. P2(1)/c] is built from isolated ten-fold coordinated Nd polyhedra. The orthorhombic structure of lead oxide nitrate [a = 7.6034(4) Angstrom, b = 5.7691(4) Angstrom, c = 18.5817(9) Angstrom, V = 815.09 Angstrom(3), S.G. Pnma] is built from double chains of edge-sharing OPb4 tetrahedra connected by nitrate groups. In order to estimate the chance of solving crystal structure of nanocrystalline powdered compounds, a comparison of the efficiency of direct methods and direct-space approaches is made from powder diffraction patterns simulated for various crystallite sizes from the crystal structure of the decomposition product gamma-Zn2P2O7. Tremayne, M The impact of powder diffraction on the structural characterization of organic crystalline materials PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES 362, 2004, 2691-2707. A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES The bulk properties of organic crystalline materials depend on their molecular and crystal structures but. as many of these materials cannot be prepared in a suitable form for conventional single-crystal diffraction studies, structural characterization and rationalization of these properties must be obtained from powder diffraction data. The recent development of direct-space structure solution methods has enabled the study of a wide range of organic materials using powder diffraction data, many of structural complexity only made tractable by these advances in methodology. These direct-space methods are based on a number of global optimization techniques including Monte Carlo. simulated annealing, genetic algorithm and differential evolution approaches. In this article, the implementation and relative efficiency and reliability, of these methods are discussed, and their impact on the structural study of organic materials is illustrated by examples of polymorphic systems, pharmaceutical, pigment and polypeptide structures and compounds used in the study of intermolecular networks. Galli, S Masciocchi, N Sironi, A Ab initio X-ray powder diffraction characterisation of molecule-based magnetic materials JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS 65, 2004, 693-696. Use of ab initio X-ray powder diffraction (XRPD) methods in the study of magnetically active species of covalent nature is presented. Selected cases are chosen in order to underline the power of XRPD methodologies, highlighting the importance of independent physicochemical information from ancillary techniques. Golobic, A Skapin, SD Suvorov, D Meden, A Solving structural problems of ceramic materials CROATICA CHEMICA ACTA 77, 2004, 435-446. Methods for the crystal structure determination from powder diffraction data are reviewed with special emphasis on the application to technical ceramics. Experimental techniques using other than laboratory X-ray, such as synchrotron radiation, neutron and electron beams, are also described. As an illustrative example, the crystal structure determinations of compounds LaNbTiO6, La0.462Nb0.614Ti0.386O3 and La0.37Nb0.889Ti0.111O3 in the ternary system of La2O3-Nb2O5-TiO2 are reported. Harris, KDM Cheung, EY How to determine structures when single crystals cannot be grown: opportunities for structure determination of molecular materials using powder diffraction data CHEMICAL SOCIETY REVIEWS 33, 2004, 526-538. Many crystalline solids cannot be prepared as single crystals of sufficient size and/or quality for structure determination to be carried out using single crystal X-ray diffraction techniques. In such cases, when only polycrystalline powders of a material are available, it is necessary instead to tackle structure determination using powder X-ray diffraction. This article highlights recent developments in the opportunities for determining crystal structures directly from powder diffraction data, focusing on the case of molecular solids and giving particular attention to the most challenging stage of the structure determination process, namely the structure solution stage. In particular, the direct-space strategy for structure solution is highlighted, as this approach has opened up new opportunities for the structure determination of molecular solids. The article gives an overview of the current state-of-the-art in structure determination of molecular solids from powder diffraction data. Relevant fundamental aspects of the techniques in this field are described, and examples are given to highlight the application of these techniques to determine crystal structures of molecular materials. Datta, S Grant, DJW Crystal structures of drugs: Advances in determination, prediction and engineering NATURE REVIEWS DRUG DISCOVERY 3, 2004, 42-57. Most marketed pharmaceuticals consist of molecular crystals. The arrangement of the molecules in a crystal determines its physical properties and, in certain cases, its chemical properties, and so greatly influences the processing and formulation of solid pharmaceuticals, as well as key drug properties such as dissolution rate and stability. A thorough understanding of the relationships between physical structures and the properties of pharmaceutical solids is therefore important in selecting the most suitable form of an active pharmaceutical ingredient for development into a drug product. In this article, we review the different crystal forms of pharmaceuticals, the challenges that they present and recent advances in crystal structure determination. We then discuss computational approaches for predicting crystal properties. Finally, we review the analysis of crystal structures in furthering crystal engineering to design novel pharmaceutical compounds with desired physical and mechanical properties. McCusker, LB The art of zeolite structure analysis RECENT ADVANCES IN THE SCIENCE AND TECHNOLOGY OF ZEOLITES AND RELATED MATERIALS, PTS A - C 154, 2004, 41-51. A number of new techniques for determining zeolite framework structures have been developed in recent years. Micron-sized single crystals can now be examined using microdiffraction instruments at synchrotron radiation facilities, direct methods of structure Solution have been adapted to the problems inherent to powder diffraction data, two zeolite-specific structure determination algorithms (FOCUS and simulated annealing) have been realized, a powder diffraction approach exploiting preferred orientation has been developed, and electron crystallography is emerging as a viable alternative to X-ray diffraction methods. Once a framework structure has been determined, the process of completing and refining the structure begins. The whole process from data collection to final structure can be long and tortuous. It is not straightforward - it is an art. 2003 Yvon, K Hydrogen in novel solid-state metal hydrides ZEITSCHRIFT FUR KRISTALLOGRAPHIE 218, 2003, 108-116. Solid-state metal hydrides display hydrogen densities close to that of liquid hydrogen and thus provide a safe and efficient way of storing hydrogen. As a result of recent neutron and synchrotron diffraction work some novel metal hydrides have been characterized that shed new light on the nature of metal-hydrogen interactions. While hydrogen appears as an anion surrounded by a large inventory of cation configurations in ionic hydrides such as Ca4Mg3H4, Ca19Mg8H54, Eu2MgD6, Eu6Mg7D26 and Eu2Mg3D10, it acts as a terminal ligand in covalently bonded hydride complexes based on p-elements such as [BH4](-) and d-elements such as [IrH5](4-) and [IrH4](5-) in the complex hydrides LiBH4 and Mg6Ir2H11, respectively. Surprisingly, hydride complexes and hydride anions can also be discerned in typically metallic (interstitial) hydrides such as NdMgNi4H4 (= Nd3+Mg+2 . [Ni4H4](5-)) and LaMg2NiD7 (= La3+Mg2+2 . [NiH4](4-) . 3H(-)). Some hydrides also reveal other interesting features such as a hydrogenation induced Ce4+ --> Ce3+ valence change in CeMn1.8Al0.2H4.4 at room temperature that is accompanied by a Mn/Al metal atom exchange over distances of similar to2.6 Angstrom, and a hydrogen induced metal-to-nonmetal transition near ambient conditions that leads from the metallic compound Mg3Ir to the red colored hydride Mg6Ir2H11. In this article recent work and some methodological aspects are highlighted. Harris, KDM Cheung, EY Structural characterization of industrially relevant polymorphic materials from powder diffraction data ORGANIC PROCESS RESEARCH & DEVELOPMENT 7, 2003, 970-976. To fully characterize a polymorphic system, it is necessary to know the structural properties of all polymorphs formed by the molecule of interest. Traditionally, single-crystal X-ray diffraction techniques have been used for this purpose, although different polymorphic forms of a given molecule can differ significantly in crystal quality and in many cases only one or a few of the polymorphs yield single crystals that are suitable for investigation by single-crystal X-ray diffraction. Structural characterization of the other polymorphs must be carried out using powder X-ray diffraction. Fortunately, recent years have seen significant developments in techniques for determining crystal structures of molecular solids directly from powder diffraction data. This article highlights the current scope of these techniques and highlights some examples involving studies of polymorphic materials of industrial relevance. Harris, KDM New opportunities for structure determination of molecular materials directly from powder diffraction data CRYSTAL GROWTH & DESIGN 3, 2003, 887-895. Although single crystal X-ray diffraction is a powerful technique for the determination of crystal and molecular structures, many solids can be prepared only as microcrystalline powders and therefore cannot be studied by single crystal diffraction techniques. For such materials, it is necessary to tackle structure determination using powder diffraction data. This article highlights recent developments in the opportunities for determining the crystal structures of molecular solids directly from powder diffraction data, focusing on the challenging structure solution stage of the structure determination process. In particular, the direct-space strategy for structure solution is highlighted, as this approach has led to significant recent advances in the structure determination of molecular solids. In the direct-space approach, a hypersurface defined by an appropriate powder diffraction R-factor is explored using global optimization techniques, and we focus on our development and application of Monte Carlo and genetic algorithm techniques within this field. Fundamental aspects are described, and examples are given to illustrate the application of the direct-space strategy to determine crystal structures of molecular materials. Neumann, MA Leusen, FJJ Engel, GE Wilke, S Conesa-Moratilla, C Recent advances in structure solution from powder diffraction data INTERNATIONAL JOURNAL OF MODERN PHYSICS B 16, 2002, 407-414. Crystal structure determination frequently is a prerequisite for the rational understanding of the solid state properties of new materials. Even though single crystal diffractometry is the method of choice when it comes to crystal structure determination, this approach is often impractical because of the difficulties involved in growing single crystals of appropriate size, High quality powder samples, on the other hand, are much easier to obtain. Using direct-space structure solution techniques, increasingly complex crystal structures can nowadays be solved directly from powder diffraction data. Combined with easy-to-use tools for model building and visualization as well as molecular mechanics and first principles Density Functional Theory (DFT) calculations, crystal structure solution from powder diffraction data is becoming a routine task. To illustrate the applicability of direct-space Monte Carlo techniques to the crystal structure solution of organic and inorganic compounds, a variety of structure solutions with the Powder Solve algorithm are presented. Recent advances include the determination of a preferred orientation correction during the structure solution search and the use of parallel tempering, a newly implemented global search algorithm. As a complementary technique, first principles DFT calculations have been used successfully to validate structure solutions and to aid the subsequent Rietveld refinement. Harris, KDM Johnston, RL Turner, GW Tedesco, E Cheung, EY Kariuki, BM Recent advances in the opportunities for solving molecular crystal structures directly from powder diffraction data MOLECULAR CRYSTALS AND LIQUID CRYSTALS 389, 2002, 123-129. For those solids that can be prepared only as microcrystalline powders, and are not suitable for investigation by single crystal diffraction methods, it is necessary to carry out structure determination using powder diffraction data. Here we highlight recent developments in the opportunities for solving molecular crystal structures from powder diffraction data, focusing on a direct-space strategy in which a hypersurface based on the powder profile R-factor R-wp is searched using a Genetic Algorithm. Recent fundamental developments are described, and the application of the method is illustrated by the structure determination of two oligopeptide materials. 2001 Chernyshev, VV Structure determination from powder diffraction RUSSIAN CHEMICAL BULLETIN 50, 2001, 2273-2292 The review surveys modern methods for the determination of unknown crystal structures of organic and inorganic compounds from powder diffraction data. The main stages of this process, from the preparation of the specimen to a search for the structural motif followed by the Rietveld refinement, are considered. The results obtained on different diffractometers using X-ray, synchrotron, and neutron radiations are demonstrated to be well reproducible. Examples of successful structure solution are cited, which provide evidence that powder diffraction is a reliable tool in establishing structures of a wide range of compounds for which single crystals are unavailable. Toraya, H Crystal structure analysis using high-resolution synchrotron radiation powder diffraction data JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 109, 2001, 903-910. The powder diffraction method is used as an indispensable technique for materials characterization. Since the advent of the Rietveld method, it is also used as a powerful mean of structure analysis of crystalline powders. The synchrotron radiation powder diffraction data are superior with respect to angular resolution to laboratory X-ray data, and they have expanded the applicability of the powder diffraction method to exploring more complex structures. A recent development of direct-space methods opened a new way for ab initio structure determination, and they are used complementarily with traditional direct methods. Introduction of the modified weight function into the least-squares procedure in Rietveld refinement improves the accuracy of structural parameters, and it provides more reliable basis for discussing details of crystal structures. Prediction Cancarevic, Z Schon, JC Jansen, M Alkali metal carbonates at high pressure ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE 632, 2006, 1437-1448. The possible existence of crystalline alkali metal carbonates as high-pressure modifications in the system M2CO3, where M = Li, Na, K, Rb, and Cs are investigated. The results agree well with the experimental observations at standard pressure, and several new modifications are proposed that should be thermodynamically stable at high and effective negative pressures. Le Bail, A Calvayrac, F Hypothetical AlF3 crystal structures JOURNAL OF SOLID STATE CHEMISTRY 179, 2006, 3159-3166. Applying a structure prediction computer programme (GRINSP = Geometrically Restrained INorganic Structure Prediction), the occurrence of 6-connected 3D networks was investigated, through AlF6 octahedra exclusive corner sharing. The five known AlF3 varieties were reproduced (alpha-, beta-, eta-, K- and tau-AlF3) and seven hypothetical models were predicted. Among these still to be synthesized AlF3 phases, one can recognize two known structure types (TICa2Ta5O15, Ba4CoTa10O30) and some easy to imagine intergrowths; however, a few others are completely unexpected, though simple. A comparison of the ab initio total energies of all the structures is provided, leading to the conclusion that the virtual models could well be viable. Florence, AJ Leech, CK Shankland, N Shankland, K Johnston, A Control and prediction of packing motifs: a rare occurrence of carbamazepine in a catemeric configuration CRYSTENGCOMM 8, 2006, 746-747. A predicted orthorhombic crystal structure of carbamazepine is isostructural with an experimentally determined dihydrocarbamazepine crystal structure, providing a rationale for synthesising a novel 1 : 1 solid solution that has carbamazepine in a rare catemeric configuration. Mellot-Draznieks, C Ferey, G Assembling molecular species into 3D frameworks: Computational design and structure solution of hybrid materials PROGRESS IN SOLID STATE CHEMISTRY 33, 2005, 187-197. We present here the computational prediction of hybrid organic-inorganic extended lattices. The production of candidate crystal structures is successfully performed by direct-space assembly of building-units using the AASBU (Automated Assembly of Secondary Building Units) method, mixing independent organic and inorganic units. Hybrid candidates that are compatible with the imposed metal:organic ratio are generated with their cell parameters, space group, atomic positions, along with their simulated diffraction pattern. Since no explicit limit regarding the nature, number, and size of the inorganic and organic units, or hybrid building-block is involved, the method offers boundless potential for exploring hybrid frameworks in terms of the topological diversity. The most appealing development arises from the computer-assisted design of hybrid frameworks. Indeed, in a significant number of systems, it is well-known that controlled synthesis conditions can promote the occurrence of specific building-units, which serve to "propagate" the infinite crystal structure. We believe that the computational approach presented herein is valuable to create virtual libraries of viable hybrid polymorphs. We further show how it has proven to be, for the first time in the realm of hybrids, a tangible route towards structure solution in direct space, exemplified here with the computational structure determination of two complex hybrid structures, MIL-100 and MIL-101. This challenging area is of special interest when high quality diffraction data are not available or when very large cell sizes are involved. The development of a structural model in direct space, starting with minimal knowledge such as the metal:organic ratio, is shown here to be possible. With such a method in hand, formerly intractable structural problems when using methods based on conventional reciprocal space become feasible in direct space. Mellot-Draznieks, C Ferey, G Simulations of inorganic crystal structures recent advances in structure elucidation CURRENT OPINION IN SOLID STATE & MATERIALS SCIENCE 7, 2003, 13-19. The aim of this paper is to show some recent developments of simulation approaches in the structure elucidation of inorganic crystalline compounds, highlighting at each step their role either as a complementary technique or as a tool to anticipate structure/properties relationships or even to imagine new inorganic architectures. Specific examples are taken in the area of zeolites to illustrate the use of energy minimizations and (N, V, T) Monte Carlo techniques as a complement to experimental diffraction approaches, typically for the disordered placement of extra-framework species (cations, water molecules). In the still extending area of the synthesis of templated open-framework inorganic structures, we show that lattice energy minimizations may possibly be used to estimate or even anticipate the structures and energetics of the related template-free structures. A third section tackles the development of more sophisticated methods for the computational design of not-yet-synthesized structures using building block concepts. Le Bail, A Inorganic structure prediction with GRINSP JOURNAL OF APPLIED CRYSTALLOGRAPHY 38, 2005, 389-395. A new computer program is described, GRINSP ( geometrically restrained inorganic structure prediction), which allows the exploration of the possibilities of occurrence of 3-, 4-, 5- and 6-connected three-dimensional networks. Hypothetical ( as well as known structure) models for binary compounds are produced with exclusive connection of polyhedra by corners, such as [MX3] triangles in M2X3 formulation, [MX4] tetrahedra in MX2 ( zeolites or dense SiO2 polymorphs), [MX5] polyhedra in M2X5, and finally [MX6] octahedra in MX3 polymorphs. Moreover, hypothetical ternary compounds are built up by combinations of either two different polyhedra or two different radii for two different cations adopting the same coordination. The cost function is based on the agreement of the model interatomic distances with ideal distances provided by the user. The Monte Carlo algorithm first finds structure candidates selected after the verification of the expected geometry, and then optimizes the cell parameters and the atomic coordinates. A satellite software ( GRINS) uses the predicted models and produces the characteristics of isostructural compounds which would be obtained by cationic substitutions. A huge list of CIF files of hypothetical boron oxide polymorphs ( including nanotubes), zeolites, aluminium and 3d-element fluorides, fluoroaluminates, borosilicates, titanosilicates, gallophosphates etc., is freely available at the PCOD ( Predicted Crystallography Open Database). Schon, JC Cancarevic, Z Jansen, M Structure prediction of high-pressure phases for alkali metal sulfides JOURNAL OF CHEMICAL PHYSICS 121, 2004, 2289-2304. For a given chemical system we present a systematic approach to predict structures, which may exist at high pressure, by investigating the global enthalpy landscape. We combine global optimizations, based on empirical potential energy functions, and local optimizations (volume, cell shape, and atomic positions) on both Hartree-Fock and density functional theory level. We predict the existence of high-pressure phases for the alkali metal sulfides of the composition M2S (M=Li, Na, K, Rb, Cs), together with the transition pressures among these phases. Gibbons, PC Hennig, RG Huett, VT Kelton, KF Ti-Zr-Ni and Ti-Hf-Ni quasicrystals and approximants as hydrogen storage alloys JOURNAL OF NON-CRYSTALLINE SOLIDS 334, 2004, 461-465. X-ray and neutron powder diffraction data previously collected from the Ti-Zr-Ni quasicrystal have been analyzed. The data were modeled by an 8/5 rational approximant (RA) that was constructed using the known structure of the 1/1 RA and then refined. Ab initio total energy calculations were made for small structures with between 81 and 123 atoms, in which atomic positions were allowed to vary while minimizing the energy. The final structure is in good agreement with that obtained from the scattering data. Interstitial sites in which H is stable in the 1/1 model, and the H binding energies, were identified. An excellent fit to existing pressure-composition isotherms was obtained, but those data cannot be inverted to obtain experimental site binding energies. At 250 degreesC the Ti-Hf-Ni alloy can be loaded with H without the formation of any detectable crystal hydride phase, which is always found in similarly loaded Ti-Zr-Ni alloys. Cancarevic, ZP Schon, JC Jansen, M Structure prediction of solids: Heuristic algorithms for local optimization on Hartree-Fock level PROGRESS IN ADVANCED MATERIALS AND PROCESSES MATERIALS SCIENCE FORUM 453-454, 2004, 71-76. In recent years, the prediction of new not-yet-synthesized solid phases and the theoretical determination of the structure of already synthesized compounds from cell information only have become of increasing importance. For example, it would be of great advantage in the identification of newly generated phases in high-pressure experiments, if one could supplement the experimental results with theoretical studies on the same system. The prediction of high pressure phases of a chemical system is realized as a two-step process: identification of structure candidates via global exploration of the energy landscapes over a range of different pressures followed by a local optimization of the candidates on ab-initio level. From the completed E(V)-curves, one could then calculate the stable phase at a given pressure and the transition pressures among the phases. In this work we will focus on the local optimization of the cell parameters and relative atom positions on the Hartree-Fock level. We present a heuristic algorithm for the full local optimization of all structural parameters and show, taking Na2S as an example, how this leads to a significant improvement in e.g. the agreement between computed and measured transition pressures. Nagayoshi, K Ikeda, T Kitaura, K Nagase, S Computational procedure of lattice energy using the ab initio MO method JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2, 2003, 233-234. Recently, we have proposed a computational procedure for calculations of lattice energies of molecular crystals using the ab initio MO method. This procedure does not use potential functions and is applicable to a variety of molecular crystals. The procedure has been successfully applied to calculation of packing structure of electron donor-acceptor complex, H3N-BF3, and hydrogen bonding crystal, CH3OH. In this work, we present a full account of the computational procedure. This method is applied to the packing structure calculations of hydrocarbon crystals, C2H2, C2H4 and C6H6. The lattice parameters optimized at the MP2/6-311++G** level are in good agreement with the experimental values. The basis set dependence of the lattice constants is also discussed for several crystals. Kratochvil, B Husak, M Jegorov, A Polymorphism and solvatomorphism of solid substances in pharmacy CHEMICKE LISTY 96, 2002, 330-335. The ability of a particular substance to exist in several different crystal forms (unsolvated or solvated) is called polymorphism or solvatomorphism. These phenomena are frequently observed in solid pharmaceuticals. Polymorphs and solvatomorphs of a compoud differ in their physical and biological properties (crystal shape, hardness, melting point, solubility, pharmacokinetics, bioavailability, etc.). This influences commercial drug formulations and their therapeutical effect, The exact theoretical prediction of all polymorphs and solvatomorphs is not yet possible. The most frequently used analytical method of detection and characterization of polymorphic and solvatomorphic forms is X-ray diffraction (single-crystal structure analysis and collection of powder patterns), Producers of original pharmaceuticals endeavour to patent all crystal forms of the developed active substance, while generic producers search for new polymorphs (solvatomorphs) or technologies. Clearly this can cause lawsuits. Van Droogenbroeck, J Swerts, B Schafer, L Van Alsenoy, C Solids modeled by ab initio crystal field methods, Part 22: The Fock matrix transformed supermolecule model and the structure determination of D-erythronic acid-3,4-carbonate JOURNAL OF COMPUTATIONAL CHEMISTRY 25, 2004, 2065-2072. To eliminate the cutoff effects in the supermolecule model (SM), the Fock matrix transformed supermolecule model (FTSM) is developed. In this model a cyclization of the cluster is performed by means of transformations of elements of the Fock matrix, thereby restoring the translational symmetry. Besides this fundamental enhancement, significant CPU time savings are realized because, in this new procedure, not all Fock matrix elements need to be calculated. The method is applied in a study of the structure of D-erythronic acid-3,4-carbonate in the crystal phase, where the new model is compared to the supermolecule model as well as the XRD experiment. The results are found to be in good agreement with experimental data. Hofmann, DWM Apostolakis, J Crystal structure prediction by data mining JOURNAL OF MOLECULAR STRUCTURE 647, 2003, 17-39. The ever increasing number of experimentally determined crystal. structures allows for the use of data mining methods to, address crystallographic questions. Here we study the application of data mining for predicting the arrangement of molecules in unit cells of unknown dimensions (crystal structure prediction) as well as in unit cells of predetermined dimensions (fractional coordinate prediction). In this work, data mining is used to derive an atom-pair potential, which is then compared-to known force fields. It is shown that the potential is-physically reasonable when the data are sufficient in quality and quantity. For validation the energy function is applied to the problems of crystal structure prediction and fractional coordinate prediction. In both cases a large number of structures-was generated and the structures were ranked according to their energies. Structure prediction was considered successful if a structure similar to the experimentally observed one was ranked highest. For crystal structure prediction the energy function is tested on an-independent set of crystal, structures taken from the P1 and P (1) over bar space groups. We show that approximately 76% of the 218 molecules tested-in, space group P1 are predicted correctly. For the more complex space group P (1) over bar the success rate is 24%. If the powder diffraction can be indexed, the problem simplifies to fractional coordinate prediction. With the assumption of known cell parameters the structure has been resolved in 92% of the test-cases for P1 and 29% for P1. Tedesco, E Giron, D Pfeffer, S Crystal structure elucidation and morphology study of pharmaceuticals in development CRYSTENGCOMM 2002, 393-400. The structural characterization of drug substances by X- ray diffraction plays a central role during the development of pharmaceuticals. While powder diffraction is usually employed for the identification of solid phases, the single crystal technique yields detailed structural information, which is needed for purity control, understanding of polymorphism or pseudo-polymorphic behavior, physico-chemical property elucidation and morphology characterization. The structure determination of three active ingredients is discussed in this context. In the first case, we have solved the structure directly from high- resolution powder X-ray data, using the `direct-space' methodology. The polymorphic behavior of the second substance has been rationalized by analyzing the intermolecular interactions and packing motifs of the two modifications in the solid state. For the third compound, we have predicted the morphology from the knowledge of its crystal structure. Solvent mixtures have been used to control the external crystal habit, based upon a detailed analysis of chemical groups emerging from the cleaved crystal surfaces of the calculated morphology. Mellot-Draznieks, C Girard, S Ferey, G Schon, JC Cancarevic, Z Jansen, M Computational design and prediction of interesting not-yet-synthesized structures of inorganic materials by using building unit concepts CHEMISTRY-A EUROPEAN JOURNAL 8, 2002, 4103-4113. The computational design of new and interesting inorganic materials is still an ongoing challenge. The motivation of these efforts is to aid the often difficult task of crystal structure determination, to rationalize different but related structure types, or to help limit the domain of structures that are possible in a given system. Over the past decade, simulation methods have continuously evolved towards the prediction of new structures using minimal input information in terms of symmetry, cell parameters, or chemical composition. So far, this task of identifying candidate structures through an analysis of the energy landscape of chemical systems has been particularly successful for predominantly ionic systems with relatively small numbers of atoms or ions in the simulation cell. After an introductory section, the second section of this work presents the historical developments of such simulation methods in this area. The following sections of the work are dedicated to the introduction of the building unit concept in simulation methods: we present simulation approaches to structure prediction employing both primary (aggregate of atoms) and secondary (aggregate of coordination polyhedra) building units. While structure prediction with primary units is a straightforward extension of established approaches, the AASBU method (automated asssembly of secondary building units) focusses on the topology of network-based structures. This method explores the possible ways to assemble predefined inorganic building units in three-dimensional space, opening the way to the manipulation of very large building units (up to 84 atoms in this work). As illustrative examples we present the prediction of candidate structures for Li4CO4, the identification of topological relationships within a family of metalphosphates, ULM-n and MIL-n, and finally the generation of new topologies by using predefined large building units such as a sodalite or a double-four-ring cage, for the prediction of new and interesting zeolite-type structures. Bond, AD Jones, W Structure prediction as a tool for solution of the crystal structures of metallo-organic complexes using powder X-ray diffraction data ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 58, 2002, 233-243. A simulated-annealing direct-space approach has been applied to predict the crystal structures of a series of metallo-organic complexes containing Zn, Cu and Ni. The prediction methodology generates a set of energetically reasonable crystal structures among which the actual structure is present, but it is not always possible to specify unambiguously the known crystal structure solely on the basis of energy. In each case, however, the ambiguity may be resolved by recourse to laboratory powder X-ray diffraction (PXRD) data. In this manner, structure prediction is shown to be a powerful tool for structure solution using PXRD data, with the additional advantage that indexing of the PXRD profile is not required at the outset. 2001 Schon, JC Jansen, M Determination, prediction, and understanding of structures, using the energy landscapes of chemical systems - Part III ZEITSCHRIFT FUR KRISTALLOGRAPHIE 216, 2001, 361-383. In the past decade, new theoretical approaches have been developed to determine, predict and understand the structure of chemical compounds. The central element of these methods has been the investigation of the energy landscape of chemical systems. Applications range from extended crystalline and amorphous compounds over clusters and molecular crystals to proteins. In this review, we are going to give an introduction to energy landscapes and methods for their investigation, together with a number of examples. These include structure prediction of extended and molecular crystals, structure prediction and folding of proteins, structure analysis of zeolites, and structure determination of crystals from powder diffraction data. Redeterminations Florence, AJ Shankland, N Shankland, K David, WIF Pidcock, E Xu, XL Johnston, A Kennedy, AR Cox, PJ Evans, JSO Steele, G Cosgrove, SD Frampton, CS Solving molecular crystal structures from laboratory X-ray powder diffraction data with DASH: the state of the art and challenges JOURNAL OF APPLIED CRYSTALLOGRAPHY 38, 2005, 249-259. The crystal structures of 35 molecular compounds have been redetermined from laboratory monochromatic capillary transmission X-ray powder diffraction data using the simulated-annealing approach embodied within the DASH structure solution package. The compounds represent industrially relevant areas ( pharmaceuticals; metal coordination compounds; nonlinear optical materials; dyes) in which the research groups in this multi-centre study are active. The molecules were specifically selected to form a series within which the degree of structural complexity (i.e. degrees of freedom in the global optimization) increased systematically, the degrees of freedom increasing with increasing number of optimizable torsion angles in the structural model and with the inclusion of positional disorder or multiple fragments ( counterions; crystallization solvent; Z' > 1). At the lower end of the complexity scale, the structure was solved with excellent reproducibility and high accuracy. At the opposite end of the scale, the more complex search space offered a significant challenge to the global optimization procedure and it was demonstrated that the inclusion of modal torsional constraints, derived from the Cambridge Structural Database, offered significant benefits in terms of increasing the frequency of successful structure solution by restricting the magnitude of the search space in the global optimization. Graphism Hinrichsen, B Dinnebier, RE Jansen, M Powder3D: An easy to use program for data reduction and graphical presentation of large numbers of powder diffraction patterns ZEITSCHRIFT FUR KRISTALLOGRAPHIE suppl 23, part 1, 2006, 231-236. The presented software facilitates data reduction of multiple powder diffraction patterns. Many operations are automated for the application to huge sets of patterns collected during diffraction experiments in dependence of time, temperature, pressure and composition. The features include basic data reduction procedures, such as background reduction, K-alpha stripping, smoothing and Le Bail fitting. Many file formats are supported to provide interoperability with GSAS, Fullprof and Crysfire (amongst others). The software is freely available for non-profit use at http://www.fkf.mpg.de/xray/. Rietveld, DDM Toby, BH R factors in Rietveld analysis: How good is good enough? POWDER DIFFRACTION 21, 2006, 67-70. The definitions for important Rietveld error indices are defined and discussed. It is shown that while smaller error index values indicate a better fit of a model to the data, wrong models with poor quality data may exhibit smaller values error index values than some superb models with very high quality data. Solovyov, LA Full-profile refinement by derivative difference minimization JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 743-749. A new method of full-profile refinement is developed on the basis of the minimization of the derivatives of the pro le difference curve. The use of the derivatives instead of the absolute difference between the observed and calculated pro le intensities allows refinement independently of the background. The procedure is tested on various powder diffraction data sets and is shown to be fully functional. Besides having the capability of powder diffraction structure analysis without modelling the background curve, the method is shown to allow the derivation of structure parameters of even higher quality than those obtained by Rietveld refinement in the presence of systematic errors in the model background function. The derivative difference minimization principles may be used in many different areas of powder diffraction and beyond. Dusek, M Petricek, V Three years of developing JANA2000 305, 2004, 267-271. FERROELECTRICS We present the latest state of the computing system JANA2000. The main improvement comparing with the previous version JANA98 consists in the possibility to use powder diffraction data of one or more three-dimensional or modulated phases. The current development of JANA2000 comprises (1) generalization of the program from four to six dimensions, (2) improvement of the powder option, (3) developing of complex tools for transformations and (4) automatic determination of the (super)space symmetry. David, WIF On the equivalence of the Rietveld method and the correlated integrated intensities method in powder diffraction JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 621-628. The Rietveld method is the most straightforward and statistically correct approach for the refinement of crystal structure parameters from powder diffraction data. The equivalent two-stage approach, involving the refinement of structural parameters based on integrated intensities extracted using the Pawley method, is extremely useful in circumstances such as the global optimization methods of structure determination, where a great many refinements need to be performed very quickly. The equivalence is emphasized in a simple mathematical relationship between the goodness of fits obtained in Rietveld, Pawley and correlated integrated intensities refinements. A rationale is given for determining the estimated standard deviations for structural variables from powder diffraction data. David, WIF Powder diffraction: Least-squares and beyond JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 109, 2004, 107-123. This paper addresses some of the underlying statistical assumptions and issues in the collection and refinement of powder diffraction data. While standard data collection and Rietveld analysis have been extremely successful in providing structural information on a vast range of materials, there is often uncertainty about the true accuracy of the derived structural parameters. In this paper, we discuss a number of topics concerning data collection and the statistics of data analysis. We present a simple new function, the cumulative chi-squared distribution, for assessing regions of misfit in a diffraction pattern and introduce a matrix which relates the impact of individual points in a powder diffraction pattern with improvements in the estimated standard deviation of refined parameters. From an experimental viewpoint, we emphasise the importance of not over-counting at low-angles and the routine use of a variable counting scheme for data collection. Data analysis issues are discussed within the framework of maximum likelihood, which incorporates the current least-squares strategies but also enables the impact of systematic uncertainties in both observed and calculated data to be reduced. Shankland, K Global Rietveld refinement JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 109, 2004, 143-154. Global optimisation methods of structure determination from powder diffraction data have risen to prominence in a relatively short space of time and they now constitute a key approach in the examination of polycrystalline molecular organic materials. A correctly formulated global optimisation approach may be regarded as a "global Rietveld refinement" that is capable of delivering accurate crystal structures from high-quality powder diffraction data. This paper focuses on how accuracy at all stages of a powder diffraction experiment impacts upon the overall structure solution process and particular attention is paid to assessing the degree of accuracy with which structures are returned from the global optimisation process. Izumi, F Beyond the ability of Rietveld analysis: MEM-based pattern fitting SOLID STATE IONICS 172, 2004, 1-6. A multipurpose pattern-fitting program, RIETAN-2000, and a software package, VENUS, for three-dimensional (3D) visualization were substantially combined to grow into an integrated system for whole-pattern fitting (w.p.f) based on the maximum entropy method (MEM). In MEM-based pattern fitting (MPF), 'observed' structure factors resulting from Rietveld analysis are analyzed by MEM to yield improved structure factors, F-c(MEM). Then, we carry out w.p.f where structure factors are fixed at the F-c(MEM)s. F-o(w.p.f) data estimated after w.p.f. are analyzed again by MEM. MEM analysis and w.p.f are alternately repeated until R factors in the latter no longer decrease. These iterative processes enable us to minimize a bias imposed by a structural model for the Rietveld analysis on final electron/nuclear densities. MPF is flexible enough to be capable of modeling static and dynamic disorder, chemical bonds, nonlocalized electrons, and anharmonic thermal motion better than the Rietveld method. Applications of MPF to structure refinements of five compounds with disordered structures have demonstrated its excellent performance and effectiveness. Izumi, F Kumazawa, S Ikeda, T Hu, WZ Yamamoto, A Oikawa, K MEM-based structure-refinement system REMEDY and its applications EPDIC 7: EUROPEAN POWDER DIFFRACTION, PTS 1 AND 2 MATERIALS SCIENCE FORUM 378-3, 2001, 59-64. A Rietveld-analysis program RIETAN was combined with MEED for a maximum-entropy method (MEM) to grow into an integrated software REMEDY. At first, 'observed' structure factors, F-o, estimated after Rietveld analysis are analyzed by the MEM to give electron/nuclear densities biased by a structural model. Then, we evaluate structure factors, (FeMEM)-M-(), by the Fourier transform of the densities and fit the whole powder pattern calculated from the F-e(MEM) data to the observed one to refine parameters irrelevant to the structure. F-o data obtained in such a manner are analyzed again by the MEM. MEM analysis and whole-pattern fitting are alternately repeated until R factors in the pattern fitting no longer decrease. REMEDY was utilized to investigate (a) positional disorder of K+ ions interlayered in KxTi2-x/3Li(x)/O-3(4), (b) atomic arrangement of K clusters in K-type LTA, and (c) nuclear/electron-density distribution in HgBa2CUO4+delta. Izumi, F Development and applications of the pioneering technology of structure refinement from powder diffraction data JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 111, 2003, 617-623. A couple of Rietveld-analysis programs, RIETAN, for angle-dispersive diffraction and time-of-flight neutron diffraction have been extensively used for structural studies of many compounds. The history of their developments is briefly reviewed. The latest versions, RIETAN-2000 for angle-dispersive diffraction and RIETAN-2001T for the Vega and Sirius diffractometers at KENS have a practical feature of partial profile relaxation. In this technique, primary profile parameters of (nearly) isolated reflections can be individually refined independent of secondary profile parameters. It was combined with split profile functions to improve fits between observed and calculated patterns, particularly in samples exhibiting anisotropic profile broadening and reflections with very large lattice-plane spacings. RIETAN-2000 and our own program for the maximum-entropy method (MEM), PRIMA, were virtually integrated into a structure-refinement system, REMEDY, whereby the pattern calculated from structure factors obtained by MEM is fit to the whole observed pattern. 'Observed' structure factors estimated at the end of the whole-pattern fitting are analyzed again by MEM. Whole-pattern fitting and MEM analysis are alternately repeated until R factors in the former no longer decrease. Applications of this technology to three inorganic compounds having highly disordered structures are demonstrated, showing its excellent performance and effectiveness. Jouanneaux, A Le Gonidec, X Fitch, AN WinMProf: Visual Rietveld software EPDIC 7: EUROPEAN POWDER DIFFRACTION, PTS 1 AND 2 MATERIALS SCIENCE FORUM 378-3, 2001, 112-117. WinMProf is a Windows application that can be used for powder diffraction analysis, with data collected at constant wavelength, using the MPROF Rietveld refinement routine. The main features of the software are described in detail. energy-dispersive X-ray diffraction Dong, YH Liu, J Li, YC Li, XD A full-pattern fitting algorithm for energy-dispersive X-ray diffraction JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 1123-1127. A full-pattern fitting algorithm for energy-dispersive X-ray diffraction is proposed, especially for high-pressure X-ray diffraction studies. The algorithm takes into account the errors in measuring the energy and the diffraction angle. A lognormal function is introduced to represent the background. All the peaks that are detectable in the diffraction spectra, including fluorescence and diffraction peaks, are considered together. Because all the data points in the spectra are used, the accuracy of the cell parameters obtained by this method is very high. This is very helpful in the analysis of the equation of state and the identification of new phases under high pressure. Size-strain, faulting Masson, O Dooryhee, E Fitch, AN Instrument line-profile synthesis in high-resolution synchrotron powder diffraction JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 286-294. An accurate method for synthesizing the instrumental line profile of high-resolution synchrotron powder diffraction instruments is presented. It is shown that the instrumental profile can be modelled by the convolution of four physical aberration functions: the equatorial intensity distribution, the monochromator and analyser transfer functions, and the axial divergence aberration function. Moreover, each equatorial aberration is related to an angle-independent function by a scale transform factor. The principles of the instrument line-profile calculation are general. They are applied in the case of the angle-dispersive powder X-ray diffraction beamline BM16 at the ESRF. The effects of each optical element on the overall instrument profile are discussed and the importance of the quality of the different optical elements of the instrument is emphasized. Finally, it is shown that the high resolution combined with the precise modelling of the instrument profile shape give access to a particle size as large as 3 mum. Kaszkur, Z Mierzwa, B Pielaszek, J Ab initio test of the Warren-Averbach analysis on model palladium nanocrystals JOURNAL OF APPLIED CRYSTALLOGRAPHY 38, 2005, 266-273. Model powder diffraction patterns were calculated via the Debye formula from atom positions of a range of energy-relaxed closed-shell cubooctahedral clusters. The energy relaxation employed the Sutton-Chen potential scheme with parameters for palladium. The assumed cluster size distribution followed lognormal distribution of a crystallite volume centred with the diameter of 5 nm, as well as two bimodal lognormal distributions centred around 4 nm and 7 nm. These models allowed an in-depth analysis of the Warren - Averbach method of separating strain and size effects in a peak shape Fourier analysis. The atom-displacement distribution in the relaxed clusters could be directly computed, as well as the strain Fourier coefficients. The results showed that in the case of the unimodal size distribution, the method can still be successfully used for obtaining the column length distribution. However, the strain Fourier coefficients obtained from three reflections ( 002, 004 and 008) cannot be reliably estimated with the Warren - Averbach method. The primary cause is a non-Gaussian strain distribution and a shift of the diffraction maximum, inherent to the nanoparticles, differing for every constituent cluster in the size distribution. For the bimodal size distributions, the obtained column length distributions tend to be shifted towards the centres of the modes and are less sensitive to the larger size mode. Balzar, D Audebrand, N Daymond, MR Fitch, A Hewat, A Langford, JI Le Bail, A Louer, D Masson, O McCowan, CN Popa, NC Stephens, PW Toby, BH Size-strain line-broadening analysis of the ceria round-robin sample JOURNAL OF APPLIED CRYSTALLOGRAPHY 37, 2004, 911-924. The results of both a line-broadening study on a ceria sample and a size - strain round robin on diffraction line-broadening methods, which was sponsored by the Commission on Powder Diffraction of the International Union of Crystallography, are presented. The sample was prepared by heating hydrated ceria at 923 K for 45 h. Another ceria sample was prepared to correct for the effects of instrumental broadening by annealing commercially obtained ceria at 1573 K for 3 h and slowly cooling it in the furnace. The diffraction measurements were carried out with two laboratory and two synchrotron X-ray sources, two constant-wavelength neutron and a time-of-flight (TOF) neutron source. Diffraction measurements were analyzed by three methods: the model assuming a lognormal size distribution of spherical crystallites, Warren-Averbach analysis and Rietveld refinement. The last two methods detected a relatively small strain in the sample, as opposed to the first method. Assuming a strain-free sample, the results from all three methods agree well. The average real crystallite size, on the assumption of a spherical crystallite shape, is 191 (5) Angstrom. The scatter of results given by different instruments is relatively small, although significantly larger than the estimated standard uncertainties. The Rietveld refinement results for this ceria sample indicate that the diffraction peaks can be successfully approximated with a pseudo-Voigt function. In a common approximation used in Rietveld refinement programs, this implies that the size-broadened profile cannot be approximated by a Lorentzian but by a full Voigt or pseudo-Voigt function. In the second part of this paper, the results of the round robin on the size - strain line-broadening analysis methods are presented, which was conducted through the participation of 18 groups from 12 countries. Participants have reported results obtained by analyzing data that were collected on the two ceria samples at seven instruments. The analysis of results received in terms of coherently diffracting, both volume-weighted and area-weighted apparent domain size are reported. Although there is a reasonable agreement, the reported results on the volume-weighted domain size show significantly higher scatter than those on the area-weighted domain size. This is most likely due to a significant number of results reporting a high value of strain. Most of those results were obtained by Rietveld refinement in which the Gaussian size parameter was not refined, thus erroneously assigning size-related broadening to other effects. A comparison of results with the average of the three-way comparative analysis from the first part shows a good agreement. Estevez-Rams, E Leoni, M Scardi, P Aragon-Fernandez, B Fuess, H On the powder diffraction pattern of crystals with stacking faults PHILOSOPHICAL MAGAZINE 83, 2003, 4045-4057. The so-called direct solution of the powder diffraction pattern for a faulted layered crystal is discussed. It is shown how, in the general case, peak profiles can be split into a symmetric and an antisymmetric component. The relationships between peak profile parameters and the underlying faulting structure, as given by the probability correlation function, are evidenced. The formalism reduces to known equations when applied to particular faulting models. Warren's equations for peak profile of fcc materials with {111} planar faulting are derived within the framework of a general theory. Possible strategies for incorporating the proposed formalism into a general powder pattern refinement procedure are also discussed. Cervellino, A Giannini, C Guagliardi, A Determination of nanoparticle structure type, size and strain distribution from X-ray data for monatomic f.c.c.-derived non-crystallographic nanoclusters JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 1148-1158. Whole-profile-fitting least-squares techniques are applied to simulated and experimental X-ray diffraction patterns of monatomic face-centred cubic (f.c. c.)derived non-crystallographic nanoclusters to extract structure and size information. Three main structure types have been considered (cuboctahedral, icosahedral and decahedral). Nanocluster structure models have been generated within an original mathematical approach so as to be independent of a specific material. For each structure type, a log-normal size distribution is assumed and a phenomenological function is introduced to model possible additional size-related strain effects. The Debye function method (modified to increase computational efficiency) has been used to obtain the diffracted intensities of the nanocluster. Tests revealed the effectiveness of the method to recognize the structure types correctly and to estimate with good accuracy structure concentrations and size distributions. Application to a thiol-passivated gold nanoparticle sample is presented. Scardi, P Leoni, M Whole powder pattern modelling ACTA CRYSTALLOGRAPHICA SECTION A 58, 2002, 190-200. A new approach for the modelling of diffraction patterns without using analytical profile functions is described and tested on ball milled f.c.c. Ni powder samples. The proposed whole powder pattern modelling (WPPM) procedure allows a one-step refinement of microstructure parameters by a direct modelling of the experimental pattern. Lattice parameter and defect content, expressed as dislocation density, outer cut-off radius, contrast factor, twin and deformation fault probabilities), can be refined together with the parameters (mean and variance) of a grain-size distribution. Different models for lattice distortions and domain size and shape can be tested to simulate or model diffraction data for systems as different as plastically deformed metals or finely dispersed crystalline powders. TEM pictures support the conclusions obtained by WPPM and confirm the validity of the proposed procedure. parallel beam with laboratory instrument Whitfield, PS Use of double Gobel mirrors with high-temperature stages for powder diffraction - a strategy to avoid severe intensity fade JOURNAL OF APPLIED CRYSTALLOGRAPHY 36, 2003, 926-930. This paper describes an approach for countering an issue that can occur when using a high-temperature stage with a diffractometer equipped with double Gobel mirrors. The optical characteristics of the dual-mirror configuration make it more susceptible to intensity loss with sample displacement than conventional parallel-beam secondary optics. This issue has been apparent in the use of a high-temperature stage on a diffractometer equipped with dual mirrors, where data could not be obtained from the full room temperature to 1273 K range without resetting the sample height manually part way through the experiment. A simple technique involving controlled contouring of the sample surface has been demonstrated to allow data to be collected uninterrupted over the full temperature range, while retaining satisfactory intensities. The extent to which this technique extends the tolerable sample displacement range has been quantified using a computer-controlled XYZ stage. Texture Morales, M Chateigner, D Lutterotti, L Ricote, J X-ray combined QTA using a CPS applied to a ferroelectric ultrastructure TEXTURES OF MATERIALS, PTS 1 AND 2 MATERIALS SCIENCE FORUM 408-4, 2002, 113-118. The new combined methodology for quantitative description of texture, structure and other microstructural parameters of thin layers using X-ray diffraction is presented and applied to the case of a ferroelectric thin film of Pb0.76Ca0.24TiO3 on a Pt/TiO2/SiO2/Si substrate. The approach allows the quantitative texture analysis of the ferroelectric thin film and the Pt electrode, refining simultaneously their structure, layers thickness, mean crystallite size and microstrain state. The layer thickness determination is estimated by the refinement of the thicknesses inserted in the absorption and volumic correction factors. The powerfulness of this methodology is discussed and compared with other approaches. Modulated structures Dusek, M Petricek, V Wunschel, M Dinnebier, RE van Smaalen, S Refinement of modulated structures against X-ray powder diffraction data with JANA2000 JOURNAL OF APPLIED CRYSTALLOGRAPHY 34, 2001, 398-404. JANA is a computer program for the refinement and analysis of periodic and aperiodic (incommensurately modulated structures and composite crystals) crystal structures. Here a new module is introduced that allows Rietveld refinements against powder diffraction data. It is shown that JANA2000 provides a state-of-the-art description of the peak profiles. A re-analysis of the low-temperature structure of (CO)(x)C-60 showed that the application of icosahedral symmetry restrictions to the C-60 molecule leads to a better description of the electron density and to a corrected position of the CO molecule as compared with a rigid-body refinement. The incommensurately modulated structure of NbTe4 has been successfully refined against X-ray powder diffraction data. The structural parameters are equal to, but less accurate, than the parameters obtained from a single-crystal study. Electron crystallography Weirich, TE Portillo, J Cox, G Hibst, H Nicolopoulos, S Ab initio determination of the framework structure of the heavy-metal oxide CsxNb2.54W2.46O14 from 100 kV precession electron diffraction data ULTRAMICROSCOPY 106, 2006, 164-175. The present work deals with the ab initio determination of the heavy metal framework in Cs-x(Nb, W)(5)O-14 from precession electron diffraction intensities. The target structure was first discovered by Lundberg and Sundberg [Ultramicroscopy 52 (1993) 429-435], who succeeded in deriving a tentative structural model from high-resolution electron microsopy (HREM) images. The metal framework of the compound was solved in this investigation via direct methods from hk0 precession electron diffraction intensities recorded with a Philips EM400 at 100 kV. A subsequent (kinematical) least-squares refinement with electron intensities yielded slightly improved co-ordinates for the I I heavy atoms in the structure. Chemical analysis of several crystallites by EDX is in agreement with the formula Cs0.44Nb2.54W2.46O14. Moreover, the structure was independently determined by Rietveld refinement from X-ray powder data obtained from a multi-phasic sample. The compound crystallises in the orthorhombic space group Pbam with refined lattice parameters a = 27.145(2), b = 21.603(2), and c = 3.9463(3) angstrom. Comparison of the framework structure from electron diffraction with the result from Rietveld refinement shows an average agreement for the heavy atoms within 0.09 angstrom. Weirich, TE First-principles calculations as a tool for structure validation in electron crystallography ACTA CRYSTALLOGRAPHICA SECTION A 60, 2004, 75-81. The crystal structures of Ti11Se4 [Weirich, Ramlau, Simon, Hovmoller & Zou ( 1996). Nature ( London), 382, 144 - 146] and Ti45Se16 [ Weirich ( 2001). Acta Cryst. A57, 183 - 191] determined previously from selected-area electron diffraction ( SAED) data have been checked for their correctness by means of total energy calculations within the non-local density functional theory. The reliability of the used method was verified by test calculations carried out for the structurally related compound Ti8Se3, which is well known from single-crystal X-ray diffraction [ Weirich, Pottgen & Simon ( 1996). Z. Kristallogr. 212, 929 - 930]. For Ti8Se3, structural models from both experiment and calculation show a perfect match (average agreement 0.01 Angstrom). This proves that the geometrical optimized models from first-principles calculation can be used as a reliable alternative when good-quality X-ray results cannot be obtained. Calculations carried out for the two structures determined from electron crystallography yielded average improvement of the atomic coordinates of 0.04 and 0.09 Angstrom for Ti11Se4 and Ti45Se16, respectively. The optimized cell parameters of the monoclinic structures ( both space group C2/m, No. 12) are a = 25.51, b = 3.43, c = 19.19 Angstrom, beta = 117.9degrees for Ti11Se4 and a = 36.31, b = 3.45, c = 16.59 Angstrom, beta = 92.1degrees for Ti45Se16. These results prove that crystals that are too small for single-crystal X-ray diffraction and are difficult to solve by powder diffraction may nevertheless be amenable to accurate structure determination by electron diffraction structure analysis using data from standard SAED and the assumption of quasi-kinematical scattering. Moreover, this study shows that geometry optimization by first-principles calculations is the perfect tool for validation and improvement of complex structural models, which are suspected to have errors owing to the poor quality of experimental data. Zou, XD Mo, ZM Hovmoller, S Li, XZ Kuo, KH Three-dimensional reconstruction of the nu-AlCrFe phase by electron crystallography ACTA CRYSTALLOGRAPHICA SECTION A 59, 2003, 526-539. The three-dimensional (3D) structure of the huge quasicrystal approximant nu-AlFeCr (space group P6(3)/m, a = 40.687 and c = 12.546 Angstrom) was solved by electron crystallography. High-resolution transmission-electron-microscopy (HREM) images and selected-area electron diffraction patterns from 13 different zone axes were combined to give a 3D potential map. 124 out of 129 unique atoms were found in the 3D map. Procedures for ab initio structure determination by 3D reconstruction are given. It is demonstrated that 3D reconstruction from HREM images is very powerful for solving structures - even very complicated ones. There is no limit in terms of the number of unique atoms in a structure that can be solved by 3D reconstruction. Dorset, DL Applications of direct methods for structure determination to problems in electron and x-ray fibre diffraction of polymers REPORTS ON PROGRESS IN PHYSICS 66, 2003, 305-338. In this review, the prospect of determining polymer crystal structures directly from single crystal electron or x-ray powder/fibre diffraction intensity data is explored. When care is taken to collect the best data set from a polymer, i.e. sampling the most intense regions of the three-dimensional reciprocal lattice, structure analyses can be carried out effectively by the conventional direct phasing methods employed in small molecule crystallography, even though the data sets are relatively small. This means that constraints imposed by multiple beam interactions in electron diffraction and reflection overlap in x-ray diffraction often do not limit the structure analysis. Several three-dimensional single crystal electron diffraction structure analyses are presented to illustrate the problems encountered. These include: polyethylene, poly(epsilon-caprolactone), isotactic poly(butene-1) form III, isotactic polypropylene beta-form,poly(p-oxybenzoate) and poly(ethylene sulfide). Techniques for sampling the complete reciprocal lattice are discussed. If an adequate number of data is collected, it is also possible to refine the structure by constrained least squares. In any case Fourier refinement is always useful. From powder x-ray diffraction the crystal structure of polyethylene has been determined by direct methods; from fibre x-ray intensities, this review reports the direct analyses of poly(epsilon-caprolactone), poly(ethylene terephthalate) and poly(tetramethyl-p-silphenylene siloxane). Rietveld methods might also be useful for the structure refinement. Direct structure analyses are advantageous in that they circumvent a priori assumptions about the molecular model and also the linkage bonds to base conformational refinement. Instead, individual atomic positions or molecular envelopes are observed directly in potential or electron density maps, to which the model can then be fit, a situation analogous to current practice in protein crystallography. Dorset, DL Correlations, convolutions and the validity of electron crystallography ZEITSCHRIFT FUR KRISTALLOGRAPHIE 218, 2003, 237-147. Although often an object of controversy, electron crystallography has emerged as a useful technique for characterization of the microcrystalline state, capable of elucidating crystal structures of unknown substances. Despite the complicated multiple scattering perturbations to diffracted intensities, experimental conditions can be adjusted to favor data collection where the experimental Patterson function still resembles the autocorrelation function of the actual crystal structure. Satisfying this condition is often sufficient to permit structure solution from such data by direct methods. While the application to organic structures may seem obvious, there are surprising successes with data sets from inorganic materials. The account given in this paper, in part, portrays work leading to the A. L. Patterson Award to the author from the American Crystallographic Association. Kolb, U Matveeva, GN Electron crystallography on polymorphic organics ZEITSCHRIFT FUR KRISTALLOGRAPHIE 218, 2003, 259-268. Organic materials, such as non-linear optical active compounds (1-(2-furyl)-3-(4-aminophenyl)-2-propene-1-one (FBAPPO) and 1-(2-furyl)-3-(4-benzamidophenyl)-2-propene-1-one (FAPPO)), polymeric materials like the metal coordinated polyelectrolyte (Fe(II) [ditopic bis-terpyridin] (MEPE)) or polymorphic materials (e.g. Cu-phthalocyanine), which do not crystallize big enough for single crystal x-ray structure analysis have been investigated by electron diffraction (ED) at 100 and 300 kV acceleration voltage. Sample preparation (direct crystallization, ultra sonication, ultra microtomy), diffraction strategies (selected area diffraction, nano diffraction, use of double-tilt rotation holder), data collection and data processing as well as structure solution strategies have been chosen dependent on the different requirements of the compounds under investigation. Structure analysis was carried out by simulation using ab initio quantum-mechanical methods like density functional theory (DFT), semi-empirical approach (MNDO/AM1/PM3) and force field packing energy calculations (DREIDING). The structure models resulting from simulation were refined kinematically as rigid bodies. Subsequently, refinements by multi-slice least squares (MSLS) procedures taking dynamical scattering into account were performed. The described combination of different methods which was used successfully on crystallizable materials is also adaptable to insoluble organic materials (e.g. pigments) and polymorphic systems. NMR Elena, B Pintacuda, G Mifsud, N Emsley, L Molecular structure determination in powders by NMR crystallography from proton spin diffusion JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 128, 2006, 9555-9560. The inability to determine molecular structures from powdered samples is a key barrier to progress in many areas of molecular and materials science. We report an approach to structure determination that combines molecular modeling with experimental spin diffusion data obtained from the high-resolution solid-state nuclear magnetic resonance of protons, and which allows the determination of the three-dimensional structure of an organic compound, in powder form and at natural isotopic abundance. Senker, J Seyfarth, L Voll, J Determination of rotational symmetry elements in NMR crystallography SOLID STATE SCIENCES 6, 2004, 1039-1052. In this work we present a consistent set of NMR experiments including high-resolution as well as wideline techniques, which allow to determine crystallographic rotational symmetry elements in crystalline solids. I D spectra acquired with fast sample spinning about the magic angle provide the number of crystal lographically inequivalent nuclei. By making use of the anisotropic properties of the chemical shift interaction the sets of crystallographically equivalent nuclei can be divided into subgroups of magnetically equivalent spins by means of radio-frequency-driven spin-diffusion wide-line exchange experiments. Maximum information can be achieved from these experiments by a combination of time- and frequency- domain analyses. We could demonstrate that the number of subgroups is equal to the order of the rotational symmetry element in which the crystallographically equivalent nuclei are arranged. From the evolution of the polarisation transfer as a function of the mixing time distances of these spins can be estimated quite accurately. Furthermore, it is often possible to distinguish between rotation and rotoinversion axes. The potential of this strategy for ab initio structure determination is demonstrated on the crystal structure of triphenyl phosphite, where eighteen molecules are arranged in a R-centred trigonal unit cell. Harris, RK NMR crystallography: the use of chemical shifts SOLID STATE SCIENCES 6, 2004, 1025-1037. Measurements of chemical shifts obtained from magic-angle spinning NMR spectra (together with quantum mechanical computations of shielding) can provide valuable information on crystallography. Examples are given of the determination of crystallographic asymmetric units, of molecular symmetry in the solid-state environment, and of crystallographic space group assignment. Measurements of full tensor components for (199)Ha have given additional coordination information. The nature of intermolecular hydrogen bonding in cortisone acetate polymorphs and solvates is obtained from chemical shift information, also involving measurement of the full tensor parameters. The resulting data have been used as restraints, built into the computation algorithm, in the analysis of powder diffraction patterns to give full crystal structures. A combination of quantum mechanical computation of shielding and measurement of proton chemical shifts (obtained by high-speed MAS) leads to the determination of the position of a proton in an intermolecular hydrogen bond. A recently-developed computer program specifically based on crystallographic repetition has been shown to give acceptable results. Moreover, NMR chemical shifts can distinguish between static and dynamic disorder in crystalline materials and can be used to determine modes and rates of molecular exchange motion. Middleton, DA Peng, X Saunders, D Shankland, K David, WIF Markvardsen, AJ Conformational analysis by solid-state NMR and its application to restrained structure determination from powder diffraction data CHEMICAL COMMUNICATIONS 17, 2002, 1876-1977. Solid-state NMR is used to dramatically improve the efficiency and reliability of molecular crystal structure determination from X-ray powder diffraction data. Femtosecond Miao, JW Chapman, HN Kirz, J Sayre, D Hodgson, KO Taking X-ray diffraction to the limit: Macromolecular structures from femtosecond X-ray pulses and diffraction microscopy of cells with synchrotron radiation ANNUAL REVIEW OF BIOPHYSICS AND BIOMOLECULAR STRUCTURE 33, 2004, 157-176. Recent work is extending the methodology of X-ray crystallography to the structure determination of noncrystalline specimens. The phase problem is solved using the oversampling method, which takes advantage of "continuous" diffraction patterns from noncrystalline specimens. Here we review the principle of this newly developed technique and discuss the ongoing experiments of imaging nonperiodic objects, such as cells and cellular structures, using coherent and bright X rays produced by third-generation synchrotron sources. In the longer run, the technique may be applicable to image single biomolecules using anticipated X-ray free electron lasers. Here, computer simulations have so far demonstrated two important steps: (a) by using an extremely intense femtosecond X-ray pulse, a diffraction pattern can be recorded from a macromolecule before radiation damage manifests itself; and (b) the phase information can be retrieved in an ab initio fashion from a set of calculated noisy diffraction patterns of single protein molecules. PDF Juhas, P Cherba, DM Duxbury, PM Punch, WF Billinge, SJL Ab initio determination of solid-state nanostructure NATURE 440, 2006, 655-658. Advances in materials science and molecular biology followed rapidly from the ability to characterize atomic structure using single crystals(1-4). Structure determination is more difficult if single crystals are not available(5). Many complex inorganic materials that are of interest in nanotechnology have no periodic long-range order and so their structures cannot be solved using crystallographic methods(6). Here we demonstrate that ab initio structure solution of these nanostructured materials is feasible using diffraction data in combination with distance geometry methods. Precise, sub-angstrom resolution distance data are experimentally available from the atomic pair distribution function (PDF)(6,7). Current PDF analysis consists of structure refinement from reasonable initial structure guesses(6,7) and it is not clear, a priori, that sufficient information exists in the PDF to obtain a unique structural solution. Here we present and validate two algorithms for structure reconstruction from precise unassigned interatomic distances for a range of clusters. We then apply the algorithms to find a unique, ab initio, structural solution for C-60 from PDF data alone. This opens the door to sub-angstrom resolution structure solution of nanomaterials, even when crystallographic methods fail. Bruhne, S Sterzel, R Uhrig, E Gross, C Assmus, W Medium range real atomic structure of face-centred icosahedral Ho9Mg26Zn65 ZEITSCHRIFT FUR KRISTALLOGRAPHIE 219, 2004, 245-258. A complementary approach to quasicrystalline atomic structures in 3-dimensional (3D) real space is presented: The atomic pair distribution function (PDF) of face centred icosahedral Ho9Mg26Zn65 [a(6D) = 2 x 5.18(3) Angstrom] has been obtained from in-house powder X-ray diffraction data (MoKalpha(1)). For the first time, full profile PDF refinements of a quasicrystal were performed: Starting with rational approximant models, derived from 1/1- and 2/1-Al-Mg-Zn, its local and medium range structure was refined (r < 27 Angstrom; R = 12.9%) using the PDF data. 85% of all atoms show Frank-Kasper (FK) type coordinations. The basic structural unit is the 3-shell, 104-atom Bergman cluster (d approximate to 15 A) comprising a void at its center. The clusters are interconnected sharing common edges and hexagonal faces of the 3rd shells. The remaining space is filled by some glue atoms (9% of all atoms), yielding an almost tetrahedrally close packed structure. All Ho atoms are surrounded by 16 neighbours (FK-polyhedron "P"). Most of them (89%) are situated in the 2nd shell and form a Ho-8 cube (edge length 5.4 Angstrom); they are completed by 12 Mg atoms to a pentagon dodecahedron. Cubes in neighbouring clusters are tilted with respect to each other; their superposition generates diffraction symmetry 2/m35. The remaining Ho atoms act as glue atoms. As a result and as can be expected for real matter, local atomic coordinations in quasicrystals are similar when compared to common crystalline intermetallic compounds. From our results, the long range quasiperiodic structure of icosahedral Mg-Zn-RE (RE = Y and some rare earths) is anticipated to be a canonical cell tiling (CCT, after Henely) decorated with Bergman clusters. Proffen, T Billinge, SJL Egami, T Louca, D Structural analysis of complex materials using the atomic pair distribution function - a practical guide ZEITSCHRIFT FUR KRISTALLOGRAPHIE 218, 2003, 132-143. Modem materials and their properties are often characterized by varying degrees of disorder. Routine crystallographic structure solution only reveals the average structure. The study of Bragg and diffuse scattering yields the local atomic arrangements holding the key to understanding increasingly complex materials. In this paper we review the pair distribution function technique used to unravel the local structure. We aim to give a practical overview and make this method easily accessible to the wider scientific community. Bruhne, S Uhrig, E Gross, C Assmus, W Local 3D real space atomic structure of the simple icosahedral Ho11Mg15Zn74 quasicrystal from PDF data CRYSTAL RESEARCH AND TECHNOLOGY 38, 2003, 1023-1036. We present a new complementary strategy to quasicrystalline structure determination: The local atomic structure of simple icosahedral (si) Ho11Mg15Zn74 [a(6D) = 5.144(3)Angstrom] in a sphere of up to r = 17Angstrom was refined using the atomic pair distribution function (PDF) from in-house X-ray powder diffraction data (MoKalpha(1), Q(max) = 13.5Angstrom(-1); R = 20.4%). The basic building block is a 105-atom Bergman-Cluster {Ho8Mg12Zn85}. Its center is occupied by a Zn atom - in contrast to a void in face centred icosahedral (fci) Ho9Mg26Zn65. The center is then surrounded by another 12 Zn atoms, forming an icosahedron (1st shell). The 2nd shell is made up of 8 Ho atoms arranged on the vertices of a cube which in turn is completed to a pentagon dodecahedron by 12 Mg atoms, the dodecahedron then being capped by 12 Zn atoms. The 3rd shell is a distorted soccer ball. of 60 Zn atoms, reflecting the higher Zn content of the si phase compared to the fci phase. In our model, 7% of all atoms are situated in between the clusters. The model corresponds to a hypothetical 1/1-approximant of the icosahedral (i) phase. The local coordinations of the single atoms are of a much distorted Frank-Kasper type and call to mind those present in 0/1-Mg2Zn11. Resonant diffraction Attfield, JP Multidataset refinement resonant diffraction, and magnetic structures JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY 109, 2004, 99-106. The scope of Rietveld and other powder diffraction refinements continues to expand, driven by improvements in instrumentation, methodology and software. This will be illustrated by examples from our research in recent years. Multidataset refinement is now commonplace; the datasets may be from different detectors, e. g., in a time-of-flight experiment, or from separate experiments, such as at several x-ray energies giving resonant information. The complementary use of x rays and neutrons is exemplified by a recent combined refinement of the monoclinic superstructure of magnetite, Fe3O4, below the 122 K Verwey transition, which reveals evidence for Fe2+/Fe3+ charge ordering. Powder neutron diffraction data continue to be used for the solution and Rietveld refinement of magnetic structures. Time-of-flight instruments on cold neutron sources can produce data that have a high intensity and good resolution at high d-spacings. Such profiles have been used to study incommensurate magnetic structures such as FeAsO4 and beta-CrPO4. A multiphase, multidataset refinement of the phase-separated perovskite (Pr0.35Y0.07Th0.04Ca0.04Sr0.5) MnO3 has been used to fit three components with different crystal and magnetic structures at low temperatures. Chen, JR Gu, YX Fan, HF Solving a superstructure from two-wavelength x-ray powder diffraction data - a simulation CHINESE PHYSICS 12, 2003, 310-314. Two different kinds of phase ambiguities are intrinsic in two-wavelength x-ray powder diffraction from acentric crystal structures having pseudo-translation symmetry. In a test calculation we have solved the problem for the first time by two different phasing procedures developed originally in single-crystal structure analysis. They are the direct method of breaking enantiomorphous phase ambiguity in protein crystallography and that of breaking translational phase ambiguity for superstructures. An artificial structure was used in the test, which is based on atomic coordinates of the known structure, SHAS (C5H6O5N3K), with the atom K replaced by Rb. The arrangement of Rb atoms possesses a subperiodicity of t = (a + b + c)/2. Two-wavelength synchrotron x-ray powder diffraction data were simulated with lambda(1)=0.0816nm and lambda(2)=0.1319nm. Overlapped reflections were uniformly decomposed at the beginning and redecomposed afterward when the partial-structure information became available. The enantiomorphous phase ambiguity was resolved only for reflections with h + k + l even. Phases of reflections with h + k + 1 odd were derived by the direct method of solving superstructures. A fragment was then obtained, which led to the complete structure in five cycles of Fourier iteration. preferred orientation Cheung, EY Harris, KDM Foxman, BM A straightforward and effective procedure to test for preferred orientation in polycrystalline samples prior to structure determination from powder diffraction data CRYSTAL GROWTH & DESIGN 3, 2003, 705-710. If a polycrystalline sample exhibits preferred orientation, the relative peak intensities in the powder diffraction pattern deviate from the intrinsic relative diffraction intensities, and can cause major difficulties in attempts to determine structural information from the powder diffraction pattern. To circumvent this problem, we report a straightforward and effective test that we use routinely as a screening procedure to ensure that polycrystalline samples are free of preferred orientation before recording high quality powder diffraction data for use in structure determination calculations. identification Le Meins, JM Cranswick, LMD Le Bail, A Results and conclusions of the internet based "Search/match round robin 2002" POWDER DIFFRACTION 18, 2003, 106-113. To test the effectiveness of phase identification software, a two-stage search/match round robin using powder X-ray diffraction data was organized, through the internet and world wide web. The first stage provided powder patterns and a vague sample origin, the second stage provided the chemistry and sample history. While the statistics are not robust, it shows that routine phase identification without chemistry can be performed, providing effective modem third generation search/match software is used; the most up to date databases are available; and well trained, experienced scientists perform the analysis. Phase transition Depmeier, W Observation and characterization of structural phase transitions by X-ray powder diffraction PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION 22, 2006, 367-377. Some of the basic properties of powder diffraction are summarized after a short introduction into the theory. Then it is described phenomenologically how various kinds of structural transformations affect the powder diffraction pattern. This is achieved on emphasizing that diffraction studies on powders are statistically more sound than those on single crystals, thus allowing the reliable determination of the generic properties of a given crystal structure. Proteins Von Dreele, RB Lee, PL Zhang, Y Protein polycrystallography ZEITSCHRIFT FUR KRISTALLOGRAPHIE Suppl 23, part 1, 2006, 3-8. The application of powder diffraction to polycrystalline proteins has seen a number of significant advances. Faster data collection techniques have reduced the sample size requirement to less than 1mg and allowed acquisition of high quality data in < 30 s permitting in situ exploration of protein crystallization, reactions and radiation damage effects. Recent developments include the formation of heavy atom derivatives that possibly provide a route to protein structure solution. Pore volumes, shapes Kuppers, H Lieba, F Spek, AL The determination of pore volumes, pore shapes and diffusion paths in microporous crystals JOURNAL OF APPLIED CRYSTALLOGRAPHY 39, 2006, 338-346. The original option SOLV of the program PLATON, which is primarily devoted to the study of organic structures, has been extended to studies of microporous inorganic crystals. The space that is available for a potential spherical guest within a pore can be regarded as being outlined by rolling a sphere of the guest's radius over the surfaces of the host atoms that form the pore. The volumes of the pores are determined in angstrom(3) and the pore shapes can be drawn. The pore volumes of several microporous phases have been calculated and compared with results obtained with other methods. An essential feature of the program is the option to vary a parameter called `probe radius', which models the size of a guest. The decision whether a void is a pore or not and the dimensionality of a pore depend on the radius of the guest, which is approximated by a sphere. This is demonstrated for the structure of the zeolite afghanite. With decreasing probe radius, cages can coalesce into larger cages and finally into channels and channel systems. The variation of the probe radius allows one to determine whether a window between adjacent pores is permeable to guests; in addition, diffusion paths in zeolites and zeolite-like structures can be determined and visualized. DFT Martinez, JR Mohn, CE Stolen, S Sondena, R What can a "quantum black-box'' do for the inorganic thermochemist? PHYSICAL CHEMISTRY CHEMICAL PHYSICS 8, 2006, 2036-2039. Enthalpies of formation of ABO(3) (A = Ca, Sr, Ba; B = Ti, Zr, Hf) from the binary constituent oxides have been calculated by ab initio density functional theory. The resulting values compare well with the large number of experimental determinations reported in literature. The trends in the calculated enthalpies of formation correlate with the difference in acidity between the binary constituent oxides. Density functional theory is shown to be a valuable tool that should be used routinely in thermochemical studies of inorganic compounds. Topology Krivovichev, S Topology of microporous structures MICRO- AND MESOPOROUS MINERAL PHASES REVIEWS IN MINERALOGY & GEOCHEMISTRY 57, 2005, 17-68. Rocha, J Lin, Z Microporous mixed octahedral-pentahedral-tetrahedral framework silicates MICRO- AND MESOPOROUS MINERAL PHASES REVIEWS IN MINERALOGY & GEOCHEMISTRY 57, 2005, 173-201. Molecule packing prediction, blind tests, etc Day, GM Motherwell, WDS An experiment in crystal structure prediction by popular vote CRYSTAL GROWTH & DESIGN 6, 2006, 1985-1990. The ability to identify the crystal structures of small molecules by visual inspection, given a list of computer-generated low-energy possibilities, has been tested in an experiment conducted at an international crystallographic conference. The surprising result of the test was that the experimentally observed crystal structures were the least popular of five choices for the two molecules included in the test, casting doubt on the reliability of crystallographic intuition as a complement to computational methods in crystal structure prediction. Day, GM Motherwell, WDS Ammon, HL Boerrigter, SXM Della Valle, RG Venuti, E Dzyabchenko, A Dunitz, JD Schweizer, B van Eijck, BP Erk, P Facelli, JC Bazterra, VE Ferraro, MB Hofmann, DWM Leusen, FJJ Liang, C Pantelides, CC Karamertzanis, PG Price, SL Lewis, TC Nowell, H Torrisi, A Scheraga, HA Arnautova, YA Schmidt, MU Verwer, P A third blind test of crystal structure prediction ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 61, 2005, 511-527. Following the interest generated by two previous blind tests of crystal structure prediction (CSP1999 and CSP2001), a third such collaborative project (CSP2004) was hosted by the Cambridge Crystallographic Data Centre. A range of methodologies used in searching for and ranking the likelihood of predicted crystal structures is represented amongst the 18 participating research groups, although most are based on the global minimization of the lattice energy. Initially the participants were given molecular diagrams of three molecules and asked to submit three predictions for the most likely crystal structure of each. Unlike earlier blind tests, no restriction was placed on the possible space group of the target crystal structures. Furthermore, Z' = 2 structures were allowed. Part-way through the test, a partial structure report was discovered for one of the molecules, which could no longer be considered a blind test. Hence, a second molecule from the same category (small, rigid with common atom types) was offered to the participants as a replacement. Success rates within the three submitted predictions were lower than in the previous tests - there was only one successful prediction for any of the three 'blind' molecules. For the 'simplest' rigid molecule, this lack of success is partly due to the observed structure crystallizing with two molecules in the asymmetric unit. As in the 2001 blind test, there was no success in predicting the structure of the flexible molecule. The results highlight the necessity for better energy models, capable of simultaneously describing conformational and packing energies with high accuracy. There is also a need for improvements in search procedures for crystals with more than one independent molecule, as well as for molecules with conformational flexibility. These are necessary requirements for the prediction of possible thermodynamically favoured polymorphs. Which of these are actually realised is also influenced by as yet insufficiently understood processes of nucleation and crystal growth. Day, GM Motherwell, WDS Jones, W Beyond the isotropic atom model in crystal structure prediction of rigid molecules: Atomic multipoles versus point charges CRYSTAL GROWTH & DESIGN 5, 2005, 1023-1033. The lattice energies of predicted and known crystal structures for 50 small organic molecules with constrained (rigid) geometries have been calculated with a model potential whose electrostatic component is described by atom-centered multipoles. In comparison to previous predictions using atomic point charge electrostatics, there are important improvements in the reliability of lattice energy minimization for the prediction of crystal structures. Half of the experimentally observed crystal structures are found either to be the global minimum energy structure or to have calculated lattice energies within 0.5 kJ/mol (0.1 kcal/mol) of the global minimum. Furthermore, in 69% of cases, there are five or fewer unobserved structures with lattice energies calculated to be lower than that of the observed structure. The results are promising for the advancement of global lattice energy minimization for the ab initio prediction of crystal structures and confirm the utility of representing electrostatic contributions to the energy with atom-centered multipoles. Day, GM Chisholm, J Shan, N Motherwell, WDS Jones, W Assessment of lattice energy minimization for the prediction of molecular organic crystal structures CRYSTAL GROWTH & DESIGN 4, 2004, 1327-1340. Lattice energy searches for theoretical low-energy crystal forms are presented for 50 small organic molecules, and we compare the experimentally observed crystal forms to these lists of hypothetical polymorphs. For each known crystal, the relative stability is calculated with respect to the global minimum energy structure, and we determine the number of unobserved structures lower in energy than the experimental form. The distributions of these relative energies and their rankings in the predicted lists are used to determine the efficacy of lattice energy minimization in crystal structure prediction. Although a simple form for the interaction energies has been used, the calculations produce almost a third of the known crystals as the global minimum in energy, and approximately a half of the known structures are within 1 kJ/mol of the global minimum. Molecules with no hydrogen-bonding capacity are most likely to be found close to the global minimum in lattice energy, while increasing the number of possible hydrogen-bond donor-acceptor combinations leads to less reliable predictions. Pidcock, E Motherwell, WDS A novel description of the crystal packing of molecules CRYSTAL GROWTH & DESIGN 4, 2004, 611-620. The question of why molecules pack to form particular crystal structures is occupying many researchers throughout the scientific community. Much emphasis has been placed on the study of intermolecular interactions and the search for "structure-directing" motifs. However, examination of experimental crystal structures contained within the Cambridge Structural Database has led us to propose a new, conceptually simple model of crystal packing that describes the arrangements molecules adopt in unit cells. The model was inspired by consideration of arrangements of boxes (with three unequal dimensions) stacked with faces touching and edges aligned. For a fixed number of boxes, there are only a limited number of arrangements possible, and these arrangements, or packing patterns, are of the same volume but different surface area. Applied to crystal structures, the model describes unit cells in terms of multiples (pattern coefficients) of molecular dimensions. The different packing patterns are not populated equally by experimental crystal structures, and it is found that the most populated packing patterns are those that are characterized by low surface area. Correlations between broadly defined molecular shapes and packing patterns have been observed which indicate that molecular aggregation is a useful method for moderating awkward (high surface area for volume) molecular shapes. A limited number of crystal structure prediction trials were performed with the reduced search space afforded by estimated unit cell dimensions (from molecular dimensions), and an increase in success rate was observed. Motherwell, WDS Ammon, HL Dunitz, JD Dzyabchenko, A Erk, P Gavezzotti, A Hofmann, DWM Leusen, FJJ Lommerse, JPM Mooij, WTM Price, SL Scheraga, H Schweizer, B Schmidt, MU van Eijck, BP Verwer, P Williams, DE Crystal structure prediction of small organic molecules: a second blind test ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 58, 2002, 647-661. The first collaborative workshop on crystal structure prediction (CSP1999) has been followed by a second workshop (CSP2001) held at the Cambridge Crystallographic Data Centre. The 17 participants were given only the chemical diagram for three organic molecules and were invited to test their prediction programs within a range of named common space groups. Several different computer programs were used, using the methodology wherein a molecular model is used to construct theoretical crystal structures in given space groups, and prediction is usually based on the minimum calculated lattice energy. A maximum of three predictions were allowed per molecule. The results showed two correct predictions for the first molecule, four for the second molecule and none for the third molecule (which had torsional flexibility). The correct structure was often present in the sorted low-energy lists from the participants but at a ranking position greater than three. The use of non-indexed powder diffraction data was investigated in a secondary test, after completion of the ab initio submissions. Although no one method can be said to be completely reliable, this workshop gives an objective measure of the success and failure of current methodologies. Motherwell, WDS Crystal structure prediction and the Cambridge Structural Database MOLECULAR CRYSTALS AND LIQUID CRYSTALS 356, 2001, 559-567. A computer program has been written to attempt prediction of likely polymorphs of small organic molecules, using a genetic algorithm. The cost function used is based not on energy but the intermolecular atom pair distances as seen in the Cambridge database, for selected similar molecules to the target. Some successful results are described, showing possible applications to molecules not easily treated with empirical energy potentials. Lommerse, JPM Motherwell, WDS Ammon, HL Dunitz, JD Gavezzotti, A Hofmann, DWM Leusen, FJJ Mooij, WTM Price, SL Schweizer, B Schmidt, MU van Eijck, BP Verwer, P Williams, DE A test of crystal structure prediction of small organic molecules ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE 56, 2000, 697-714. A collaborative workshop was held in May 1999 at the Cambridge Crystallographic Data Centre to test how well currently available methods of crystal structure prediction perform when given only the atomic connectivity for an organic compound. A blind test was conducted on a selection of four compounds and a wide range of methodologies representing the principal computer programs currently available were used. There were 11 participants who were allowed to propose at most three structures for each compound. No program gave consistently reliable results. However, seven proposed structures were close to an experimental one and were classified as 'correct'. One compound occurred in two polymorphs, but only one form was predicted correctly among the calculated structures. The basic problem with lattice energy based methods of crystal structure prediction is that many structures are found within a few kJ mol(-1) of the global minimum. The fine detail of the force-field methodology and parametrization influences the energy ranking within each method. Nevertheless, present methods may be useful in providing a set of structures as possible polymorphs for a given molecular structure. SDPD Round Robin A. Le Bail & L. Cranswick, SDPD Round Robin 2002 Results IUCr Commission on Powder Diffraction Newsletter 29 (2003) 31-34. A. Le Bail and L.M.D. Cranswick, Revisiting the 1998 SDPD Round Robin IUCr Commission on Powder Diffraction Newsletter 25 (2001) 7-9.