DOI: 10.17188/1206556
title: Materials Data on Mg(FeO2)2 by Materials Project

description: MgFe2O4 is Spinel-like structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are eight inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–59°. There is two shorter (1.98 Å) and two longer (2.01 Å) Mg–O bond length. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three MgO4 tetrahedra, corners with three FeO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.08–2.11 Å. In the third Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–59°. There are a spread of Mg–O bond distances ranging from 1.99–2.02 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four FeO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.08–2.11 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six FeO4 tetrahedra, edges with two MgO6 octahedra, and edges with four equivalent FeO6 octahedra. There are two shorter (2.09 Å) and four longer (2.10 Å) Mg–O bond lengths. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six FeO4 tetrahedra, edges with two MgO6 octahedra, and edges with four FeO6 octahedra. All Mg–O bond lengths are 2.10 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five FeO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with five FeO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.07–2.11 Å. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six FeO4 tetrahedra, edges with two MgO6 octahedra, and edges with four FeO6 octahedra. There are three shorter (2.09 Å) and three longer (2.11 Å) Mg–O bond lengths. There are twelve inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three MgO4 tetrahedra, corners with three FeO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.11 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent FeO4 tetrahedra, edges with two MgO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.11 Å. In the third Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six MgO6 octahedra and corners with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–57°. There are a spread of Fe–O bond distances ranging from 1.92–1.98 Å. In the fourth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent MgO4 tetrahedra, corners with four FeO4 tetrahedra, edges with three MgO6 octahedra, and edges with three FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.09 Å. In the fifth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–58°. There is three shorter (1.93 Å) and one longer (1.99 Å) Fe–O bond length. In the sixth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six MgO6 octahedra and corners with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–58°. There are a spread of Fe–O bond distances ranging from 1.91–1.97 Å. In the seventh Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra, edges with two equivalent FeO6 octahedra, and edges with four MgO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.04–2.08 Å. In the eighth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six MgO6 octahedra and corners with six FeO6 octahedra. The corner-sharing octahedral tilt angles are 57°. There are a spread of Fe–O bond distances ranging from 1.91–1.98 Å. In the ninth Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one MgO4 tetrahedra, corners with five FeO4 tetrahedra, edges with three MgO6 octahedra, and edges with three FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.10 Å. In the tenth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six MgO6 octahedra and corners with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 56–58°. There are a spread of Fe–O bond distances ranging from 1.91–1.98 Å. In the eleventh Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent MgO4 tetrahedra, corners with three equivalent FeO4 tetrahedra, edges with two MgO6 octahedra, and edges with four FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.00–2.10 Å. In the twelfth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three MgO6 octahedra and corners with nine FeO6 octahedra. The corner-sharing octahedra tilt angles range from 57–58°. There are a spread of Fe–O bond distances ranging from 1.93–1.99 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Fe3+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two equivalent Fe3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms. In the fourth O2- site, O2- is bonded to four Fe3+ atoms to form a mixture of distorted corner and edge-sharing OFe4 trigonal pyramids. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Fe3+ atoms. In the sixth O2- site, O2- is bonded to one Mg2+ and three Fe3+ atoms to form distorted OMgFe3 trigonal pyramids that share corners with two OFe4 trigonal pyramids and edges with three OMgFe3 trigonal pyramids. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms. In the eighth O2- site, O2- is bonded to one Mg2+ and three Fe3+ atoms to form a mixture of distorted corner and edge-sharing OMgFe3 trigonal pyramids. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms. In the tenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+ and two Fe3+ atoms. In the eleventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+ and two Fe3+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms. In the fourteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms. In the sixteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms. In the seventeenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to two Mg2+ and two Fe3+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+ and two Fe3+ atoms. In the nineteenth O2- site, O2- is bonded to two Mg2+ and two equivalent Fe3+ atoms to form distorted corner-sharing OMg2Fe2 trigonal pyramids. In the twentieth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms. In the twenty-first O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms. In the twenty-second O2- site, O2- is bonded to four Fe3+ atoms to form distorted OFe4 trigonal pyramids that share corners with five OMg2Fe2 trigonal pyramids and edges with three OMgFe3 trigonal pyramids. In the twenty-third O2- site, O2- is bonded to one Mg2+ and three Fe3+ atoms to form distorted OMgFe3 trigonal pyramids that share corners with five OMg2Fe2 trigonal pyramids and edges with three OFe4 trigonal pyramids. In the twenty-fourth O2- site, O2- is bonded to one Mg2+ and three Fe3+ atoms to form distorted OMgFe3 trigonal pyramids that share corners with three equivalent OMg2Fe2 trigonal pyramids and edges with three OFe4 trigonal pyramids.