DOI: 10.17188/1301568
title: Materials Data on Mg4Sc3(SiO3)8 by Materials Project

description: Mg4Sc3(SiO3)8 crystallizes in the monoclinic P2 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 distorted MgO6 octahedra that share corners with four SiO4 tetrahedra, edges with three ScO6 octahedra, and edges with two equivalent SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.06–2.36 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, an edgeedge with one MgO6 octahedra, edges with two equivalent ScO6 octahedra, and edges with two equivalent SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.05–2.42 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 ScO6 octahedra, and edges with three MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.23 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted MgO6 octahedra that share corners with four SiO4 tetrahedra, an edgeedge with one ScO6 octahedra, edges with two equivalent MgO6 octahedra, and edges with two equivalent SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.42 Å. There are three inequivalent Sc+2.67+ sites. In the first Sc+2.67+ site, Sc+2.67+ is bonded to six O2- atoms to form distorted ScO6 octahedra that share corners with six SiO4 tetrahedra, an edgeedge with one MgO6 octahedra, and edges with two equivalent ScO6 octahedra. There are a spread of Sc–O bond distances ranging from 1.99–2.43 Å. In the second Sc+2.67+ site, Sc+2.67+ is bonded to six O2- atoms to form ScO6 octahedra that share corners with six SiO4 tetrahedra, edges with two equivalent MgO6 octahedra, and edges with two equivalent ScO6 octahedra. There are a spread of Sc–O bond distances ranging from 2.13–2.19 Å. In the third Sc+2.67+ site, Sc+2.67+ is bonded to six O2- atoms to form ScO6 octahedra that share corners with six SiO4 tetrahedra and edges with five MgO6 octahedra. There are a spread of Sc–O bond distances ranging from 2.09–2.28 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 MgO6 octahedra, corners with two ScO6 octahedra, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 31–63°. 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 two ScO6 octahedra, corners with three MgO6 octahedra, and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 33–63°. There are a spread of Si–O bond distances ranging from 1.59–1.68 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one MgO6 octahedra, corners with three ScO6 octahedra, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 30–57°. 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 two ScO6 octahedra, corners with three MgO6 octahedra, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 33–63°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to two Sc+2.67+ and one Si4+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Mg2+, two Sc+2.67+, and one Si4+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Sc+2.67+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a distorted T-shaped geometry to one Mg2+, one Sc+2.67+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Mg2+ and two Si4+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Mg2+ and two Si4+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Mg2+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a distorted T-shaped geometry to one Mg2+, one Sc+2.67+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a distorted T-shaped geometry to two Mg2+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+, one Sc+2.67+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Mg2+, one Sc+2.67+, and one Si4+ atom.