Re: [sdpd] Reference materials for calibration and indexing

[Lachlan Cranswick <L.M.D.Cranswick...@dl.ac.uk>]

>The latest addition into PowBase is In2O3, cubic
>variety (a=10.119 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.

While the above implies it can be used out of the bottle(?):
Does In2O3 "need" any annealing or can it be used reliably
out of the bottle?  Also, what is the general cost for 10 to
100 grams?

----

Is it possible to get a "fixed" slit data collection of this
where all the slit and geometry settings are noted?

I would be quite eager to try out a Fundamental Parameters
fit using Koalariet/XFIT.

I am quite a fan of Ian Madsen's suggestion of using annealed
cubic Y2O3.  Except you normally have to anneal it yourself.
This is 10.6 A IA3 cubic.  This has performed well in the past
using Fundamental Parameters fitting to look at diffractometer
geometry and alignment.

Lachlan.


Lachlan M. D. Cranswick

Collaborative Computational Project No 14 (CCP14)
     for Single Crystal and Powder Diffraction
Daresbury Laboratory, Warrington, WA4 4AD U.K
Tel: +44-1925-603703  Fax: +44-1925-603124
E-mail: l.cranswick...@dl.ac.uk  Ext: 3703  Room C14
                            http://www.ccp14.ac.uk