DOI: 10.17188/1711541
title: Materials Data on Mg3Fe3(PO4)4 by Materials Project

description: Mg3Fe3(PO4)4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six PO4 tetrahedra, a cornercorner with one MgO5 trigonal bipyramid, a cornercorner with one FeO5 trigonal bipyramid, and edges with two FeO5 trigonal bipyramids. There are a spread of Mg–O bond distances ranging from 2.06–2.20 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six PO4 tetrahedra, corners with two FeO5 trigonal bipyramids, an edgeedge with one MgO5 trigonal bipyramid, and an edgeedge with one FeO5 trigonal bipyramid. There are a spread of Mg–O bond distances ranging from 2.08–2.20 Å. In the third Mg2+ site, Mg2+ is bonded to five O2- atoms to form distorted MgO5 trigonal bipyramids that share a cornercorner with one MgO6 octahedra, corners with three PO4 tetrahedra, an edgeedge with one MgO6 octahedra, an edgeedge with one PO4 tetrahedra, and an edgeedge with one FeO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 56°. There are a spread of Mg–O bond distances ranging from 1.99–2.14 Å. There are three inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share a cornercorner with one MgO6 octahedra, corners with three PO4 tetrahedra, an edgeedge with one MgO6 octahedra, an edgeedge with one PO4 tetrahedra, and an edgeedge with one FeO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 59°. There are a spread of Fe–O bond distances ranging from 2.02–2.22 Å. In the second Fe2+ site, Fe2+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share a cornercorner with one MgO6 octahedra, corners with three PO4 tetrahedra, an edgeedge with one MgO6 octahedra, an edgeedge with one PO4 tetrahedra, and an edgeedge with one MgO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 59°. There are a spread of Fe–O bond distances ranging from 2.02–2.21 Å. In the third Fe2+ site, Fe2+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share a cornercorner with one MgO6 octahedra, corners with three PO4 tetrahedra, an edgeedge with one MgO6 octahedra, an edgeedge with one PO4 tetrahedra, and an edgeedge with one FeO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 60°. There are a spread of Fe–O bond distances ranging from 2.02–2.22 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 MgO6 octahedra, a cornercorner with one MgO5 trigonal bipyramid, corners with two FeO5 trigonal bipyramids, and an edgeedge with one FeO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 31–51°. There are a spread of P–O bond distances ranging from 1.54–1.57 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three MgO6 octahedra, a cornercorner with one MgO5 trigonal bipyramid, corners with two FeO5 trigonal bipyramids, and an edgeedge with one MgO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 33–53°. There is three shorter (1.55 Å) and one longer (1.56 Å) P–O bond length. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three MgO6 octahedra, a cornercorner with one MgO5 trigonal bipyramid, corners with two FeO5 trigonal bipyramids, and an edgeedge with one FeO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 33–52°. There are a spread of P–O bond distances ranging from 1.54–1.57 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three MgO6 octahedra, corners with three FeO5 trigonal bipyramids, and an edgeedge with one FeO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 32–52°. There is three shorter (1.55 Å) and one longer (1.57 Å) P–O bond length. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Fe2+, and one P5+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Fe2+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+, one Fe2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Fe2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted T-shaped geometry to one Mg2+, one Fe2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted T-shaped geometry to two Mg2+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted T-shaped geometry to one Mg2+, one Fe2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted T-shaped geometry to one Mg2+, one Fe2+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe2+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe2+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe2+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe2+, and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Mg2+ and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe2+, and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe2+, and one P5+ atom.