DOI: 10.17188/1205879
title: Materials Data on Cr3(PO4)4 by Materials Project

description: Cr3(PO4)4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are three inequivalent Cr4+ sites. In the first Cr4+ site, Cr4+ is bonded to five O2- atoms to form CrO5 trigonal bipyramids that share a cornercorner with one CrO6 octahedra, corners with three PO4 tetrahedra, an edgeedge with one CrO6 octahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There are a spread of Cr–O bond distances ranging from 1.78–2.01 Å. In the second Cr4+ site, Cr4+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one CrO5 trigonal bipyramid. There are a spread of Cr–O bond distances ranging from 1.92–2.24 Å. In the third Cr4+ site, Cr4+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra and a cornercorner with one CrO5 trigonal bipyramid. There are a spread of Cr–O bond distances ranging from 1.94–2.24 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CrO6 octahedra and a cornercorner with one CrO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 24–44°. 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 CrO6 octahedra. The corner-sharing octahedra tilt angles range from 36–50°. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CrO6 octahedra and corners with two equivalent CrO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 38–54°. There are a spread of P–O bond distances ranging from 1.52–1.63 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CrO6 octahedra and an edgeedge with one CrO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 34–53°. There are a spread of P–O bond distances ranging from 1.50–1.65 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Cr4+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr4+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to two Cr4+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cr4+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr4+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr4+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr4+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr4+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr4+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the twelfth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr4+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr4+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr4+ and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr4+ and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr4+ and one P5+ atom.