Materials Data on MgFe(SiO3)2 by Materials Project

MgFe(SiO3)2 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six SiO4 tetrahedra, edges with three equivalent FeO6 octahedra, and an edgeedge with one SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 1.99–2.70 Å. Fe2+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six SiO4 tetrahedra, edges with two equivalent FeO6 octahedra, and edges with three equivalent MgO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.07–2.28 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent FeO6 octahedra, corners with four equivalent MgO6 octahedra, and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–75°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent MgO6 octahedra, corners with three equivalent FeO6 octahedra, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 27–60°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+, two equivalent Fe2+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+, one Fe2+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to one Mg2+, one Fe2+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+ and two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Mg2+ and two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+, two equivalent Fe2+, and one Si4+ atom.