DOI: 10.17188/1323019
title: Materials Data on MgCrNiP2O9 by Materials Project

description: MgCrNiP2O9 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Mg–O bond distances ranging from 2.09–2.29 Å. In the second Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Mg–O bond distances ranging from 2.07–2.29 Å. In the third Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Mg–O bond distances ranging from 2.09–2.29 Å. In the fourth Mg2+ site, Mg2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Mg–O bond distances ranging from 2.07–2.29 Å. There are four inequivalent Cr4+ sites. In the first Cr4+ site, Cr4+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two NiO6 octahedra, corners with three PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 49–50°. There are a spread of Cr–O bond distances ranging from 1.77–2.05 Å. In the second Cr4+ site, Cr4+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two NiO6 octahedra, corners with three PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cr–O bond distances ranging from 1.77–2.05 Å. In the third Cr4+ site, Cr4+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two NiO6 octahedra, corners with three PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cr–O bond distances ranging from 1.77–2.05 Å. In the fourth Cr4+ site, Cr4+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two NiO6 octahedra, corners with three PO4 tetrahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Cr–O bond distances ranging from 1.77–2.05 Å. There are four inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two CrO6 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent NiO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Ni–O bond distances ranging from 2.02–2.13 Å. In the second Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two CrO6 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent NiO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Ni–O bond distances ranging from 2.02–2.13 Å. In the third Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two CrO6 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent NiO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of Ni–O bond distances ranging from 2.02–2.13 Å. In the fourth Ni2+ site, Ni2+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two CrO6 octahedra, corners with four PO4 tetrahedra, and edges with two equivalent NiO6 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. There are a spread of Ni–O bond distances ranging from 2.01–2.14 Å. There are eight inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two NiO6 octahedra and corners with three CrO6 octahedra. The corner-sharing octahedra tilt angles range from 5–52°. There are a spread of P–O bond distances ranging from 1.52–1.55 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two NiO6 octahedra and corners with three CrO6 octahedra. The corner-sharing octahedra tilt angles range from 5–52°. There are a spread of P–O bond distances ranging from 1.52–1.55 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two NiO6 octahedra and corners with three CrO6 octahedra. The corner-sharing octahedra tilt angles range from 6–52°. There are a spread of P–O bond distances ranging from 1.52–1.55 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two NiO6 octahedra and corners with three CrO6 octahedra. The corner-sharing octahedra tilt angles range from 6–52°. There are a spread of P–O bond distances ranging from 1.52–1.55 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two NiO6 octahedra and an edgeedge with one CrO6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of P–O bond distances ranging from 1.55–1.59 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two NiO6 octahedra and an edgeedge with one CrO6 octahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of P–O bond distances ranging from 1.55–1.59 Å. In the seventh P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two NiO6 octahedra and an edgeedge with one CrO6 octahedra. The corner-sharing octahedral tilt angles are 55°. There are a spread of P–O bond distances ranging from 1.55–1.59 Å. In the eighth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two NiO6 octahedra and an edgeedge with one CrO6 octahedra. The corner-sharing octahedral tilt angles are 55°. There are a spread of P–O bond distances ranging from 1.55–1.58 Å. There are thirty-five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Ni2+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Ni2+, and one P5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Ni2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Ni2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Ni2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Ni2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Ni2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Ni2+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ni2+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Cr4+ and two Ni2+ atoms. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Cr4+ and two Ni2+ atoms. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Cr4+ and two Ni2+ atoms. In the sixteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Cr4+ and two Ni2+ atoms. In the seventeenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the nineteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the twentieth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the twenty-first O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the twenty-third O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the twenty-fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the twenty-fifth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the twenty-sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the twenty-seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Cr4+, and one P5+ atom. In the twenty-eighth O2- site, O2- is bonded in an L-shaped geometry to one Cr4+ and one P5+ atom. In the twenty-ninth O2- site, O2- is bonded in an L-shaped geometry to one Cr4+ and one P5+ atom. In the thirtieth O2- site, O2- is bonded in an L-shaped geometry to one Cr4+ and one P5+ atom. In the thirty-first O2- site, O2- is bonded in an L-shaped geometry to one Cr4+ and one P5+ atom. In the thirty-second O2- site, O2- is bonded in a linear geometry to one Cr4+ and one P5+ atom. In the thirty-third O2- site, O2- is bonded in a linear geometry to one Cr4+ and one P5+ atom. In the thirty-fourth O2- site, O2- is bonded in a linear geometry to one Cr4+ and one P5+ atom. In the thirty-fifth O2- site, O2- is bonded in a linear geometry to one Cr4+ and one P5+ atom.