DOI: 10.17188/1350771
title: Materials Data on MgSiO3 by Materials Project

description: MgSiO3 crystallizes in the orthorhombic Pca2_1 space group. The structure is three-dimensional. there are four 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 2.04–2.25 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with four SiO4 tetrahedra, edges with three equivalent MgO6 octahedra, and edges with two SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.35 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with three equivalent MgO5 square pyramids. There are a spread of Mg–O bond distances ranging from 2.03–2.24 Å. In the fourth Mg2+ site, Mg2+ is bonded to five O2- atoms to form distorted MgO5 square pyramids that share corners with four 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 2.02–2.32 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four MgO6 octahedra, a cornercorner with one MgO5 square pyramid, and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–62°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four MgO6 octahedra, a cornercorner with one MgO5 square pyramid, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 23–61°. There are a spread of Si–O bond distances ranging from 1.60–1.68 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four MgO6 octahedra, a cornercorner with one MgO5 square pyramid, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO5 square pyramid. The corner-sharing octahedra tilt angles range from 27–60°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four MgO6 octahedra, a cornercorner with one MgO5 square pyramid, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 26–61°. There are a spread of Si–O bond distances ranging from 1.61–1.68 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+ and 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 4-coordinate geometry to three Mg2+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to 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. In the seventh O2- site, O2- is bonded to three Mg2+ and one Si4+ atom to form distorted corner-sharing OMg3Si trigonal pyramids. In the eighth O2- site, O2- is bonded in a distorted T-shaped geometry to two Mg2+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+ and two equivalent Si4+ atoms. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+ and two equivalent Si4+ atoms. In the eleventh O2- site, O2- is bonded in a distorted T-shaped geometry to two Mg2+ and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom.