[sdpd] RE: Reference materials for calibration and indexing

["Yokochi, Alexandre" <alex.yokochi...@orst.edu>]

Armel,

	The suggestion of In2O3 is very welcome.  I too have struggled with finding a good calibration standard.  For reflection mode I have hit on ZrW2O8, cubic, P2(1)3 (at r.t.) or P a -3 (at 150 C or higher), with a = 9.1567 (at r.t.) and has well characterized thermal expansion behaviour (as studied by neutron diffraction).  Much higher linear absorption coefficient than NAC too, which is nice for reflection mode.
Cheers, AlexY
Dr. Alexandre F. T. Yokochi
Assistant Professor (Senior Research)
Director, X-ray Crystallographic Facilities
Department of Chemistry
Oregon State University
Corvallis, OR 97331-4003

Ph#  (541) 737-6724	Email: alex.yokochi...@orst.edu
Fax# (541) 737-2062	Web Page: crystal.chem.orst.edu/~alexy (temporarily unavailable)

-----Original Message-----
The latest addition into PowBase is In2O3, cubic
variety (a.119 A; space group Ia3).

http://www.cristal.org/powbase/
This compound would be a nice reference material to be mixed
with your unknown sample for indexing. No preferred
orientation occured on a sample from CERAC Inc.
The minimal FWHM is near of 0.06° (2-theta), without
annealing. Unfortunately, 3 of the 7 first reflections are very
weak. Anyway, this material may replace NAC (Na2Ca3Al2F14)
if you need a more absorbing sample.

Other suggestions of inexpensive reference materials welcome.