Materials Data on CaSnP2O7 by Materials Project

Abstract

CaSnP2O7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Ca2+ is bonded to seven O2- atoms to form distorted CaO7 pentagonal bipyramids that share corners with two equivalent SnO6 octahedra, corners with five PO4 tetrahedra, edges with two equivalent SnO6 octahedra, an edgeedge with one CaO7 pentagonal bipyramid, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 64–78°. There are a spread of Ca–O bond distances ranging from 2.38–2.65 Å. Sn2+ is bonded to six O2- atoms to form distorted SnO6 octahedra that share corners with two equivalent CaO7 pentagonal bipyramids, corners with six PO4 tetrahedra, an edgeedge with one SnO6 octahedra, and edges with two equivalent CaO7 pentagonal bipyramids. There are a spread of Sn–O bond distances ranging from 2.30–2.71 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent SnO6 octahedra, corners with two equivalent CaO7 pentagonal bipyramids, a cornercorner with one PO4 tetrahedra, and an edgeedge with one CaO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 44–69°. There are a spread of P–O bond distances ranging from 1.52–1.62 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent SnO6 octahedra, corners with three equivalent CaO7 pentagonal bipyramids, and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 61–66°. There are a spread of P–O bond distances ranging from 1.53–1.67 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+, one Sn2+, and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+, one Sn2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to one Ca2+, one Sn2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one Ca2+, two equivalent Sn2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to one Ca2+, one Sn2+, and one P5+ atom.