Materials Data on MgSiO3 by Materials Project

Abstract

MgSiO3 crystallizes in the monoclinic P2_1/c 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 distorted MgO6 octahedra that share corners with six equivalent SiO6 octahedra, corners with four equivalent SiO4 tetrahedra, and edges with three equivalent MgO6 octahedra. The corner-sharing octahedra tilt angles range from 47–64°. There are a spread of Mg–O bond distances ranging from 2.03–2.34 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with three equivalent SiO6 octahedra, corners with three equivalent SiO4 tetrahedra, edges with five MgO6 octahedra, and a faceface with one SiO6 octahedra. The corner-sharing octahedra tilt angles range from 35–43°. There are a spread of Mg–O bond distances ranging from 1.93–2.19 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 seven MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–66°. There are a spread of Si–O bond distances ranging from 1.59–1.68 Å. In the second Si4+ site, Si4+ is bonded to six O2- atoms to form SiO6 octahedra that share corners with nine MgO6 octahedra, edges with three equivalent SiO6 octahedra, and a faceface with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 35–64°. There are a spread of Si–O bond distances ranging from 1.75–1.98 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Mg2+ and two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a trigonal planar geometry to one Mg2+ and two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted see-saw-like geometry to two Mg2+ and two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded to three Mg2+ and two equivalent Si4+ atoms to form distorted edge-sharing OMg3Si2 trigonal bipyramids.