Materials Data on MgSiO3 by Materials Project

Abstract

MgSiO3 is Esseneite-derived structured and crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. there are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.17–2.44 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.05–2.07 Å. In the third Mg2+ site, Mg2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Mg–O bond distances ranging from 2.08–2.72 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 two equivalent MgO6 octahedra and corners with two equivalent SiO6 octahedra. The corner-sharing octahedra tilt angles range from 45–55°. There are a spread of Si–O bond distances ranging from 1.63–1.70 Å. In the second Si4+ site, Si4+ is bonded to six O2- atoms to form corner-sharing SiO6 octahedra. There is two shorter (1.78 Å) and four longer (1.81 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four equivalent O2- atoms to form corner-sharing SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. All Si–O bond lengths are 1.65 Å. In the fourth Si4+ site, Si4+ is bonded to four equivalent O2- atoms to form SiO4 tetrahedra that share corners with four equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 58°. All Si–O bond lengths are 1.65 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Mg2+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mg2+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Mg2+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Mg2+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded to three Mg2+ and one Si4+ atom to form a mixture of distorted edge and corner-sharing OMg3Si tetrahedra. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one Si4+ atom.