Materials Data on MgSiO3 by Materials Project

Abstract

MgSiO3 crystallizes in the monoclinic C2/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 MgO6 octahedra that share corners with four equivalent SiO6 octahedra, edges with two equivalent MgO6 octahedra, and edges with four equivalent SiO6 octahedra. The corner-sharing octahedra tilt angles range from 13–23°. There are a spread of Mg–O bond distances ranging from 2.03–2.13 Å. In the second Mg2+ site, Mg2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Mg–O bond distances ranging from 1.96–2.49 Å. Si4+ is bonded to six O2- atoms to form SiO6 octahedra that share corners with two equivalent MgO6 octahedra, edges with two equivalent MgO6 octahedra, and edges with three equivalent SiO6 octahedra. The corner-sharing octahedra tilt angles range from 13–23°. There are a spread of Si–O bond distances ranging from 1.72–1.90 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to three Mg2+ and two equivalent Si4+ atoms to form a mixture of distorted edge and corner-sharing OMg3Si2 square pyramids. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to one Mg2+ and two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a distorted see-saw-like geometry to two Mg2+ and two equivalent Si4+ atoms.