A new langbeinite-type phosphate: K₂AlSn(PO₄)₃

Abstract

Key indicators: single-crystal X-ray study; T = 296 K; mean (P-O) = 0.005 Å; disorder in main residue; R factor = 0.029; wR factor = 0.074; data-to-parameter ratio = 13.7.Single crystals of the title compound, dipotassium aluminium tin(IV) tris[phosphate(V)], K 2 AlSn(PO 4 ) 3 , were synthesized by a high temperature reaction in a platinum crucible. In the structure, the Al III and Sn IV atoms occupy the same site on a threefold rotation axis with occupational disorder in a 1:1 ratio. In the three-dimensional structure, Al/SnO 6 octahedra and PO 4 tetrahedra are interconnected via their vertices, yielding a [Al/SnP 3 O 12 ] n framework. The K atoms (site symmetry 3) reside in the large cavities delimited by the [Al/ SnP 3 O 12 ] n framework, and are surrounded by 12 O atoms. Related literature

A Langbeinite-Type Yttrium Phosphate LiCs2Y2(PO4)3

“…In their structures, a common feature is that two adjacent metal octahedra are interlinked via corner-sharing nonmetallic tetrahedra. As for langbeinite-type phosphates, although metal octahedra can be substituted by different kinds of tetravalent and bivalent or trivalent metal cations, the basic unit is still a [M 2 (PO 4 ) 3 ] fragment . This unique framework of the connection mode is conducive to ion substitution without changes in the langbeinite-type structure.…”