DOI: 10.17188/1320499
title: Materials Data on MgFePO5 by Materials Project

description: MgFePO5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to five O2- atoms to form distorted MgO5 trigonal bipyramids that share corners with two equivalent FeO6 octahedra, corners with two PO4 tetrahedra, edges with two equivalent FeO6 octahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–58°. There are a spread of Mg–O bond distances ranging from 1.95–2.26 Å. In the second Mg2+ site, Mg2+ is bonded to five O2- atoms to form distorted MgO5 trigonal bipyramids that share corners with two equivalent FeO6 octahedra, corners with two PO4 tetrahedra, edges with two equivalent FeO6 octahedra, and an edgeedge with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–57°. There are a spread of Mg–O bond distances ranging from 1.95–2.23 Å. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four PO4 tetrahedra, corners with two equivalent MgO5 trigonal bipyramids, and edges with two equivalent MgO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°. There are a spread of Fe–O bond distances ranging from 1.90–2.18 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent FeO6 octahedra, corners with four PO4 tetrahedra, corners with two equivalent MgO5 trigonal bipyramids, and edges with two equivalent MgO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°. There are a spread of Fe–O bond distances ranging from 1.90–2.17 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 four FeO6 octahedra, corners with two MgO5 trigonal bipyramids, and an edgeedge with one MgO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 37–51°. There is two shorter (1.55 Å) and two longer (1.56 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four FeO6 octahedra, corners with two MgO5 trigonal bipyramids, and an edgeedge with one MgO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 36–50°. There is two shorter (1.55 Å) and two longer (1.56 Å) P–O bond length. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe3+, and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe3+, and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe3+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe3+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted T-shaped geometry to one Mg2+, one Fe3+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe3+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe3+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted T-shaped geometry to one Mg2+, one Fe3+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a trigonal planar geometry to one Mg2+ and two Fe3+ atoms. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+ and two Fe3+ atoms.