Dear Armel,
thanks for the information. Obviously, this phase is solid solution with a
coupled substitution of Na and P against Ca and Si.
CaNaPO4 (ICSD 27957) also gives an almost similiar XRD pattern.
I will use the atom information of one of these two phases and replace Na
and P for Ca and Si or the other way around.
We need to quantify the amount of the alpha-Na2Ca4(PO4)2SiO4, because it is
used as a binder in one of our refractories.
We also use the EVA software here.
Kind regards and thanks,
Stefan
Dr. Stefan Melzer
Corus RD&T
Ceramics Research Centre
PO Box 10000
1970CA IJmuiden
The Netherlands
T +31 (0)251 499571
F +31 (0)251 470489
|---------+---------------------------->
| | Armel Le Bail |
| | <[EMAIL PROTECTED]>|
| | |
| | 09-03-2005 13:53 |
| | Please respond to|
| | rietveld_l |
| | |
|---------+---------------------------->
>----------------------------------------------------------------------------------------------------------------|
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| To: rietveld_l@ill.fr
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| cc:
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| Subject: Re: alpha-Na2Ca4(PO4)2SiO4
|
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>does anyone knows the atomic positions for
>PDF No. 33-1229 alpha-Na2Ca4(PO4)2SiO4 Space-group P-3m1
>or where I can find it?
>I coudn't find in the ICSD database 2/2004.
Producing a calculated powder pattern from 33-1229
and using a search/match software suggests that this
compound is highly related to the mineral Nagelschmidtite
(03-9796), itself of "unknown" structure, and to Ca2SiO4
(86-0401), well known... The fit on the figure is obtained
after some cell parameters tuning :
http://sdpd.univ-lemans.fr/33-1229.jpg
The ICDD-JCPDS PDF is a mine for solving structures said
to be unknown in the PDF ;-). A pity that the guys at
the ICDD-JCPDS do not check their own data against their
own data ;;;-).
Best wishes,
Armel
