DOI: 10.17188/1319499
title: Materials Data on MgFeO2 by Materials Project

description: MgFeO2 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 to five O2- atoms to form MgO5 trigonal bipyramids that share corners with four MgO4 tetrahedra, corners with two equivalent FeO5 trigonal bipyramids, edges with two equivalent MgO5 trigonal bipyramids, and a faceface with one FeO5 trigonal bipyramid. There are a spread of Mg–O bond distances ranging from 2.06–2.15 Å. In the second Mg2+ site, Mg2+ is bonded to five O2- atoms to form MgO5 trigonal bipyramids that share corners with four MgO4 tetrahedra, corners with two equivalent FeO5 trigonal bipyramids, edges with two equivalent MgO5 trigonal bipyramids, and a faceface with one FeO5 trigonal bipyramid. There are a spread of Mg–O bond distances ranging from 2.06–2.15 Å. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with two equivalent MgO4 tetrahedra, corners with four MgO5 trigonal bipyramids, corners with four FeO5 trigonal bipyramids, and an edgeedge with one FeO5 trigonal bipyramid. There are a spread of Mg–O bond distances ranging from 1.95–2.01 Å. In the fourth Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with two equivalent MgO4 tetrahedra, corners with four MgO5 trigonal bipyramids, corners with four FeO5 trigonal bipyramids, and an edgeedge with one FeO5 trigonal bipyramid. There are a spread of Mg–O bond distances ranging from 1.96–2.02 Å. There are four inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (1.98 Å) and two longer (2.16 Å) Fe–O bond lengths. In the second Fe2+ site, Fe2+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share corners with four MgO4 tetrahedra, corners with two equivalent MgO5 trigonal bipyramids, an edgeedge with one MgO4 tetrahedra, edges with two equivalent FeO5 trigonal bipyramids, and a faceface with one MgO5 trigonal bipyramid. There are a spread of Fe–O bond distances ranging from 2.06–2.30 Å. In the third Fe2+ site, Fe2+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share corners with four MgO4 tetrahedra, corners with two equivalent MgO5 trigonal bipyramids, an edgeedge with one MgO4 tetrahedra, edges with two equivalent FeO5 trigonal bipyramids, and a faceface with one MgO5 trigonal bipyramid. There are a spread of Fe–O bond distances ranging from 2.04–2.30 Å. In the fourth Fe2+ site, Fe2+ is bonded in a square co-planar geometry to four O2- atoms. There are a spread of Fe–O bond distances ranging from 1.99–2.17 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to one Mg2+ and three Fe2+ atoms to form distorted OMgFe3 tetrahedra that share corners with two equivalent OMgFe3 tetrahedra, corners with four OMg3Fe2 trigonal bipyramids, and an edgeedge with one OMg3Fe2 trigonal bipyramid. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Mg2+ and two equivalent Fe2+ atoms. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Mg2+ and two equivalent Fe2+ atoms. In the fourth O2- site, O2- is bonded to one Mg2+ and three Fe2+ atoms to form distorted OMgFe3 tetrahedra that share corners with two equivalent OMgFe3 tetrahedra, corners with four OMg3Fe2 trigonal bipyramids, and an edgeedge with one OMg3Fe2 trigonal bipyramid. In the fifth O2- site, O2- is bonded to three Mg2+ and two equivalent Fe2+ atoms to form distorted OMg3Fe2 trigonal bipyramids that share corners with four OMgFe3 tetrahedra, an edgeedge with one OMgFe3 tetrahedra, and edges with two equivalent OMg3Fe2 trigonal bipyramids. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to three Mg2+ and two equivalent Fe2+ atoms. In the seventh O2- site, O2- is bonded to three Mg2+ and two equivalent Fe2+ atoms to form distorted OMg3Fe2 trigonal bipyramids that share corners with four OMgFe3 tetrahedra, an edgeedge with one OMgFe3 tetrahedra, and edges with two equivalent OMg3Fe2 trigonal bipyramids. In the eighth O2- site, O2- is bonded in a 5-coordinate geometry to three Mg2+ and two equivalent Fe2+ atoms.