Materials Data on MgSiO3 by Materials Project

Abstract

MgSiO3 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with five MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.20 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six SiO4 tetrahedra, edges with three equivalent MgO6 octahedra, and an edgeedge with one SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.54 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 five MgO6 octahedra, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 29–61°. There are a spread of Si–O bond distances ranging from 1.61–1.68 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with seven MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–72°. 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 trigonal planar geometry to one Mg2+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted T-shaped geometry to two Mg2+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+ and two equivalent Si4+ atoms.