Materials Data on MgFe2BO5 by Materials Project

Fe2MgBO5 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with three FeO6 octahedra, edges with two equivalent MgO6 octahedra, and edges with four FeO6 octahedra. The corner-sharing octahedra tilt angles range from 61–62°. There are a spread of Mg–O bond distances ranging from 1.99–2.17 Å. There are three inequivalent Fe+2.50+ sites. In the first Fe+2.50+ site, Fe+2.50+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent FeO6 octahedra, edges with two equivalent MgO6 octahedra, and edges with five FeO6 octahedra. The corner-sharing octahedra tilt angles range from 19–61°. There are a spread of Fe–O bond distances ranging from 2.02–2.13 Å. In the second Fe+2.50+ site, Fe+2.50+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two equivalent MgO6 octahedra and edges with six FeO6 octahedra. The corner-sharing octahedral tilt angles are 62°. There are two shorter (2.06 Å) and four longer (2.23 Å) Fe–O bond lengths. In the third Fe+2.50+ site, Fe+2.50+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with four equivalent FeO6 octahedra, edges with four equivalent MgO6 octahedra, and edges with four FeO6 octahedra. The corner-sharing octahedral tilt angles are 19°. There are four shorter (2.15 Å) and two longer (2.16 Å) Fe–O bond lengths. B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.39 Å) and one longer (1.40 Å) B–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Mg2+, one Fe+2.50+, and one B3+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe+2.50+ and one B3+ atom. In the third O2- site, O2- is bonded to one Mg2+ and four Fe+2.50+ atoms to form OMgFe4 square pyramids that share corners with two equivalent OMgFe4 square pyramids, corners with three equivalent OMgFe3 tetrahedra, edges with three equivalent OMgFe4 square pyramids, and an edgeedge with one OMgFe3 tetrahedra. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Mg2+, one Fe+2.50+, and one B3+ atom. In the fifth O2- site, O2- is bonded to one Mg2+ and three Fe+2.50+ atoms to form distorted OMgFe3 tetrahedra that share corners with three equivalent OMgFe4 square pyramids, corners with three equivalent OMgFe3 tetrahedra, and an edgeedge with one OMgFe4 square pyramid.