Materials Data on MgFe(SiO3)2 by Materials Project

Abstract

MgFe(SiO3)2 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Mg2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.07–2.29 Å. Fe2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are two shorter (2.13 Å) and six longer (2.31 Å) Fe–O bond lengths. Si4+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing SiO6 octahedra. The corner-sharing octahedra tilt angles range from 39–43°. There are a spread of Si–O bond distances ranging from 1.79–1.84 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to one Mg2+, two equivalent Fe2+, and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Mg2+, one Fe2+, and two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Fe2+ and two equivalent Si4+ atoms. In the fourth O2- site, O2- is bonded to two equivalent Mg2+ and two equivalent Si4+ atoms to form distorted corner-sharing OMg2Si2 tetrahedra.