Acta Cryst. (2009). E65, i74  [ doi:10.1107/S1600536809040008 ]

Synchrotron study of the garnet-type oxide Li₆CaSm₂Ta₂O₁₂

C.-Y. Yoo, S.-C. Kim, S.-S. Lee and S.-J. Kim

Abstract: Hexalithium calcium disamarium(III) ditantalum(V) dodecaoxide, Li₆CaSm₂Ta₂O₁₂, crystallizes in a cubic garnet-type structure. In the crystal structure, disordered Li atoms occupy two crystallographic sites. One Li has a tetrahedral coordination environment in the oxide lattice, whereas the other Li atom occupies a significantly distorted octahedral site, with site occupancies for the two Li atoms of 0.26 (7) and 0.44 (2), respectively. Ca and Sm atoms are statistically distributed over the same crystallographic position with a occupancy of 2/3 for Sm and of 1/3 for Ca, and are eightfold coordinated by O atoms. The TaO₆ octahedron is joined to six others via corner-sharing LiO₄ tetrahedra. One Li and the O atoms lie on general positions, while the other atoms are situated on special positions. The Sm/Ca position has 222, Ta has , and the tetrahedrally coordinated Li atom has site symmetry.

Online 7 October 2009

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