Materials Data on MgSiO3 by Materials Project

Abstract

MgSiO3 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are two inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to four O2- atoms to form MgO4 trigonal pyramids that share a cornercorner with one MgO6 octahedra, a cornercorner with one SiO6 octahedra, corners with two equivalent SiO4 tetrahedra, corners with two equivalent MgO4 trigonal pyramids, and edges with two equivalent MgO6 octahedra. The corner-sharing octahedra tilt angles range from 41–63°. There are a spread of Mg–O bond distances ranging from 1.88–2.15 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with two equivalent SiO6 octahedra, a cornercorner with one SiO4 tetrahedra, a cornercorner with one MgO4 trigonal pyramid, edges with two equivalent MgO6 octahedra, edges with two equivalent SiO6 octahedra, and edges with two equivalent MgO4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 28–43°. There are a spread of Mg–O bond distances ranging from 1.92–2.48 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to six O2- atoms to form distorted SiO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with three equivalent SiO4 tetrahedra, a cornercorner with one MgO4 trigonal pyramid, edges with two equivalent MgO6 octahedra, and edges with two equivalent SiO6 octahedra. The corner-sharing octahedra tilt angles range from 28–43°. There are a spread of Si–O bond distances ranging from 1.65–2.06 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra, corners with three equivalent SiO6 octahedra, corners with two equivalent SiO4 tetrahedra, and corners with two equivalent MgO4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 36–71°. There are a spread of Si–O bond distances ranging from 1.63–1.69 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Mg2+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Mg2+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Mg2+ and two equivalent Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+ and two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to three Si4+ atoms. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Mg2+ and one Si4+ atom.