solid solution

JOUKJ@CRYS.CHEM.UVA.NL
Mon, 14 Nov 1994 12:51 +0100 (MET)

>On Nov 14, 11:09am, patrizia canton wrote:
>> Subject: Solid solution
>> hello
>> I have a problem:two ions randomly distributed with the same atomic position
>> into the same cell, one ion is predominant, the other one is in minor
>> quantity (at the moment I don't know exactly this quantity). Is it possible
>to
>> consider these two atoms simultaneously? If it is, how can I do it?
>> thanks
>>-- End of excerpt from patrizia canton
>
>If you have any decent Rietveld software this should be straightforward
>enough. Give the atomic positions for the two ions the same codewords so
>that when these are refined they will stay the same. Refine the ionic
>occupancies and temperature factors for the two ions with separate codewords.
>You should then be able to find out the quantities of your two ions.
>
>
>--
>tony bell A.M.T.Bell@dl.ac.uk
>crystallographer and marathon runner (but not necessarily in that order :-))
>engineering and physical science research council
>daresbury laboratory, daresbury, warrington, cheshire, UK. WA4 4AD.

Since the depencies of occupational and temerature parameters in a
crystallographic least-squares program this solution will work only if the site
of the two ions is fully occupied and the two occupation parameters are
contraint in such a way that they add up to 1.
An other solution may be to set an overall temperature factor for both atoms.

Jacob Jansen
joukj@crsy.chem.uva.nl

FromSMTP%"xray@iris.unipress.waw.pl (Stanislaw Gierlotka)" 14-NOV-1994 14:26:03.34
Date: Mon, 14 Nov 94 13:43:21 +0100
From: xray@iris.unipress.waw.pl (Stanislaw Gierlotka)
Subject: TiO2

Hello everybody!
We are now working on a quant. phase analysis of samples containing
TiO2 polymorphs: rutile and anatase. The question is:
Does anybody know anything about temperature factors in those
structures. Refinement for X-ray laboratory data gives results
that look suspicious.
Thanks in advance for any suggestions.
Stan
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