DOI: 10.17188/1262303
title: Materials Data on Cr7(PO4)6 by Materials Project

description: Cr7(PO4)6 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are four inequivalent Cr+2.57+ sites. In the first Cr+2.57+ site, Cr+2.57+ is bonded to five O2- atoms to form distorted CrO5 trigonal bipyramids that share a cornercorner with one CrO6 octahedra, corners with five PO4 tetrahedra, and edges with two CrO6 octahedra. The corner-sharing octahedral tilt angles are 64°. There are a spread of Cr–O bond distances ranging from 2.07–2.22 Å. In the second Cr+2.57+ site, Cr+2.57+ is bonded to six O2- atoms to form CrO6 octahedra that share a cornercorner with one CrO6 octahedra, corners with six PO4 tetrahedra, an edgeedge with one CrO6 octahedra, and an edgeedge with one CrO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 65°. There are a spread of Cr–O bond distances ranging from 1.93–2.13 Å. In the third Cr+2.57+ site, Cr+2.57+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two equivalent CrO6 octahedra, corners with six PO4 tetrahedra, and corners with two equivalent CrO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 65°. There are a spread of Cr–O bond distances ranging from 2.06–2.37 Å. In the fourth Cr+2.57+ site, Cr+2.57+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra, an edgeedge with one CrO6 octahedra, and an edgeedge with one CrO5 trigonal bipyramid. There are a spread of Cr–O bond distances ranging from 1.94–2.13 Å. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with six CrO6 octahedra and a cornercorner with one CrO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 27–53°. There are a spread of P–O bond distances ranging from 1.50–1.59 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with five CrO6 octahedra and corners with two equivalent CrO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 34–63°. There are a spread of P–O bond distances ranging from 1.51–1.58 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CrO6 octahedra and corners with two equivalent CrO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 24–60°. There is two shorter (1.53 Å) and two longer (1.57 Å) P–O bond length. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Cr+2.57+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.57+ and one P5+ atom. In the third O2- site, O2- is bonded in a trigonal planar geometry to two Cr+2.57+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr+2.57+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr+2.57+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.57+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr+2.57+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Cr+2.57+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr+2.57+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Cr+2.57+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.57+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to two Cr+2.57+ and one P5+ atom.