Materials Data on Mg(FeO2)2 by Materials Project

MgFe2O4 is Spinel-like structured and crystallizes in the tetragonal P4_122 space group. The structure is three-dimensional. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent FeO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with four equivalent FeO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.07–2.09 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 six equivalent FeO4 tetrahedra, edges with two equivalent FeO6 octahedra, and edges with four equivalent MgO6 octahedra. There is two shorter (1.97 Å) and four longer (1.98 Å) Fe–O bond length. In the second Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with six equivalent MgO6 octahedra and corners with six equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 53–61°. There is two shorter (1.91 Å) and two longer (1.94 Å) Fe–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Mg2+ and two Fe3+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+ and three Fe3+ atoms.