Materials Data on MgSiO3 by Materials Project

Abstract

MgSiO3 is Esseneite-derived structured and crystallizes in the monoclinic P2/c space group. The structure is three-dimensional. there are six 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 2.05–2.24 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 equivalent SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.01–2.32 Å. In the third 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 2.03–2.22 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with six 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 2.01–2.67 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with two equivalent MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.06–2.17 Å. In the sixth Mg2+ site, Mg2+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are two shorter (2.01 Å) and two longer (2.06 Å) Mg–O bond lengths. 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 five MgO6 octahedra, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 22–60°. There are a spread of Si–O bond distances ranging from 1.60–1.68 Å. In the second 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 46–75°. There are a spread of Si–O bond distances ranging from 1.62–1.69 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 45–61°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four MgO6 octahedra, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 24–60°. There are a spread of Si–O bond distances ranging from 1.60–1.69 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded to three Mg2+ and one Si4+ atom to form a mixture of distorted edge and corner-sharing OMg3Si trigonal pyramids. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to two Mg2+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+ and two equivalent Si4+ atoms. In the fourth O2- site, O2- is bonded to three Mg2+ and one Si4+ atom to form a mixture of distorted edge and corner-sharing OMg3Si trigonal pyramids. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Mg2+ and two equivalent Si4+ atoms. In the seventh O2- site, O2- is bonded to three Mg2+ and one Si4+ atom to form a mixture of distorted edge and corner-sharing OMg3Si trigonal pyramids. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Mg2+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Si4+ atoms. In the tenth O2- site, O2- is bonded to three Mg2+ and one Si4+ atom to form a mixture of distorted edge and corner-sharing OMg3Si trigonal pyramids. 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 3-coordinate geometry to one Mg2+ and two equivalent Si4+ atoms.