The title compound, dipotassium tri-mu-arsenato-scandium(III)-tin(IV), is the first arsenate-containing langbeinite to be characterized by single-crystal methods and crystallizes in the aristotype P2(1)3 cubic symmetry for this structure type in which the K+ ions and the octahedral scandium and tin cations lie on crystallographic threefold axes. The Sc-III and Sn-IV ions show a slight segregation over the two octahedral sites, with Sc/Sn populations of 0.582 (5):0.418 (5) on one site and 0.418 (5):0.582 (5) on the other. Bond-valence-sum calculations indicate that the K+ ions are significantly underbonded in this structure and the O atoms show large anisotropic displacement parameters, as also seen in other langbeinites. The crystal studied was found to be a merohedral twin with a 0.690 (16):0.310 (16) domain ratio.
|Number of pages||3|
|Journal||Acta Crystallographica Section C, Crystal Structure Communications|
|Publication status||Published - Jul 2010|
- phosphate langbeinites