Rietveld refinement of langbeinite-type K(2)YHf(PO(4))(3)
Ivan V Ogorodnyk1, Igor V Zatovsky, Nikolay S Slobodyanik
1Department of Inorganic Chemistry, Taras Shevchenko National University, 64 Volodymyrska Str., 01601 Kyiv, Ukraine.
Abstract:
Potassium yttrium hafnium tris-(orthophosphate) belongs to the langbeinite-family and is built up from [MO(6)] octa-hedra [in which the positions of the two independent M sites are mutually occupied by Y and Hf in a 0.605 (10):0.395 (10) ratio] and [PO(4)] tetra-hedra connected via vertices into a three-dimensional framework. This framework is penetrated by large closed cavities in which the two independent K atoms are located; one of the K atoms is nine-coordinated and the other is 12-coordinated by surrounding O atoms. The K, Y and Hf atoms lie on threefold rotation axes, whereas the P and O atoms are located in general positions.
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