>In the case of your new query about Ca4Al2(SO4)O6*12H2O, I guess you have
>eliminated the mineral "Chukrovite" Ca4Al2(SO4)F12*12H2O as a possibly
>related structure ? JSSC B115 (1995) P. 126-139. Space group Fd3-
>CELL A=16.80 B=16.80 C=16.80 AL=90. BE=90. GA=90. V=4741.6 Z=8
>SGR FD3-s
>
>And remember, these X-ray people don't always get the light atoms right :-)
Hmmm, Alan, and sometimes the Databanks divide the formula by 2 or the
(X-Ray) structure determination distinguishes between H2O and OH.... So there
is a Ca4Al2(SO4)O6*12H2O under the Collection code 100138 in the ICSD
with the formula : (Ca2 Al (O H)6) (S0.5 O2 (O H2)3) = H12 Al Ca2 O11 S.5
Signed : an X-ray people (neutron people don't always make a simple
preliminary X-ray pattern:-)
Armel Le Bail, Laboratoire des Fluorures URA CNRS 449
Faculte des Sciences, Universite du Maine, F-72017 Le Mans, France
http://fluo.univ-lemans.fr:8001/ and/or http://pcb4122.univ-lemans.fr/