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 in a 5-coordinate geometry to five O2- atoms. There are a spread of Mg–O bond distances ranging from 2.00–2.32 Å. In the second Mg2+ site, Mg2+ is bonded to four O2- atoms to form distorted MgO4 tetrahedra that share corners with two equivalent MgO4 tetrahedra, corners with three equivalent SiO4 tetrahedra, and a cornercorner with one SiO5 trigonal bipyramid. There are a spread of Mg–O bond distances ranging from 1.93–2.07 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to five O2- atoms to form distorted SiO5 trigonal bipyramids that share a cornercorner with one MgO4 tetrahedra and edges with two equivalent SiO5 trigonal bipyramids. There are a spread of Si–O bond distances ranging from 1.67–1.87 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent SiO4 tetrahedra and corners with three equivalent MgO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.65 Å) Si–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. 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 T-shaped geometry to one Mg2+ and two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a T-shaped geometry to one Mg2+ and two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded in a distorted T-shaped geometry to two Mg2+ and one Si4+ atom.