DOI: 10.17188/1753562
title: Materials Data on Cr3(P2O7)2 by Materials Project

description: Cr3(P2O7)2 crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one Cr3(P2O7)2 sheet oriented in the (0, 0, 1) direction. there are three inequivalent Cr+2.67+ sites. In the first Cr+2.67+ site, Cr+2.67+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.93–2.23 Å. In the second Cr+2.67+ site, Cr+2.67+ is bonded to five O2- atoms to form CrO5 trigonal bipyramids that share corners with five PO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 2.02–2.24 Å. In the third Cr+2.67+ site, Cr+2.67+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cr–O bond distances ranging from 2.03–2.62 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 two equivalent CrO6 octahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one CrO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 38–50°. There are a spread of P–O bond distances ranging from 1.51–1.57 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CrO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–42°. There are a spread of P–O bond distances ranging from 1.50–1.66 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one PO4 tetrahedra and corners with three equivalent CrO5 trigonal bipyramids. 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 two equivalent CrO6 octahedra, a cornercorner with one PO4 tetrahedra, and a cornercorner with one CrO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 23–46°. There are a spread of P–O bond distances ranging from 1.49–1.62 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two Cr+2.67+ and one P5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Cr+2.67+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.67+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.67+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.67+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr+2.67+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr+2.67+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr+2.67+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr+2.67+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr+2.67+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr+2.67+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms.