Crystal structure of a microlite-group mineral NaCaTa2O6

Reference:
• Andrade, M.B., Atencio, D., Menezes Filho, L.A.D, Ellena, J. (2011): Crystal structure of a microlite-group mineral with formula near NaCaTa2O6F from Morro Redondo quarry, Coronel Murta, Minas Gerais, Brazil. Canadian Mineralogist, 49, 615-621.

Abstract:
We present electron-microprobe and single-crystal X-ray-diffraction data for a microlite-group mineral with a formula near NaCaTa2O6F from the Morro Redondo mine, Coronel Murta, Minas Gerais, Brazil. On the basis of these data, the formula is A(Na0.88Ca0.88Pb0.02vacancy0.22)2.00 B(Ta1.70Nb0.14Si0.12As0.04)2.00 X[(O5.75(OH)0.25]6.00 Y(F0.73vacancy0.27)1.00. According to the new nomenclature for the pyrochlore-supergroup minerals, it is intermediate between fluornatromicrolite and "fluorcalciomicrolite". The crystal structure, Fd-3m, a = 10.4396(12) Å, has been refined to an R1 value of 0.0258 (wR2 = 0.0715) for 107 reflections (MoK radiation). There is a scarcity of crystal-chemical data for pyrochlore-supergroup minerals in the literature. A compilation of these data is presented here.



Edited 1 time(s). Last edit at 06/21/2011 06:50AM by Marco E. Ciriotti.

Marco:

You missed my named, I am a co-author on that paper, I was who found the specimens, did the first SEM analysis and handled it to Daniel and Marcelo to run the crystal structure.

Luiz

Ohps! Sorry Luiz, very sorry.
Now is OK. Thank you.
Ciao. Marco

Thank you very much, Marco.

Luiz