Materials Data on MgFeBO4 by Materials Project
MgFeBO4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three equivalent FeO6 octahedra, edges with two equivalent MgO6 octahedra, and edges with two equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 55–64°. There are a spread of Mg–O bond distances ranging from 2.02–2.18 Å. Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with three equivalent MgO6 octahedra, edges with two equivalent MgO6 octahedra, and edges with four equivalent FeO6 octahedra. The corner-sharing octahedra tilt angles range from 55–64°. There are a spread of Fe–O bond distances ranging from 2.01–2.16 Å. B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.42 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to one Mg2+, two equivalent Fe3+, and one B3+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Mg2+, one Fe3+, and one B3+ atom. In the third O2- site, O2- is bonded to one Mg2+ and three equivalent Fe3+ atoms to form a mixture of distorted edge and corner-sharing OMgFe3 tetrahedra. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Mg2+ and one B3+ atom.