DOI: 10.17188/1654701
title: Materials Data on Mg17(SiO3)20 by Materials Project

description: Mg17(SiO3)20 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are nine inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four equivalent SiO4 tetrahedra and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.13 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.07–2.12 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with five MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.12 Å. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with three MgO6 octahedra. There are two shorter (2.05 Å) and four longer (2.14 Å) Mg–O bond lengths. In the fifth Mg site, Mg is bonded in a distorted rectangular see-saw-like geometry to four O atoms. There are two shorter (2.01 Å) and two longer (2.07 Å) Mg–O bond lengths. In the sixth Mg site, Mg is bonded to six O atoms to form distorted MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with five MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.15 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with three MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.16 Å. In the eighth Mg site, Mg is bonded to six O atoms to form distorted MgO6 octahedra that share corners with four equivalent SiO4 tetrahedra and edges with six MgO6 octahedra. There are four shorter (2.11 Å) and two longer (2.32 Å) Mg–O bond lengths. In the ninth Mg site, Mg is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Mg–O bond distances ranging from 2.04–2.44 Å. There are five inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–59°. All Si–O bond lengths are 1.64 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–62°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 35–60°. There are a spread of Si–O bond distances ranging from 1.61–1.68 Å. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–61°. All Si–O bond lengths are 1.64 Å. In the fifth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 36–59°. There are a spread of Si–O bond distances ranging from 1.61–1.67 Å. There are sixteen inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the second O site, O is bonded in a bent 150 degrees geometry to two equivalent Si atoms. In the third O site, O is bonded in a trigonal non-coplanar geometry to three Mg atoms. In the fourth O site, O is bonded in a bent 150 degrees geometry to two equivalent Si atoms. In the fifth O site, O is bonded to three Mg and one Si atom to form a mixture of distorted edge and corner-sharing OMg3Si trigonal pyramids. In the sixth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the seventh O site, O is bonded to three Mg and one Si atom to form a mixture of distorted edge and corner-sharing OMg3Si trigonal pyramids. In the eighth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the ninth O site, O is bonded in a 2-coordinate geometry to one Mg and two Si atoms. In the tenth O site, O is bonded in a rectangular see-saw-like geometry to three Mg and one Si atom. In the eleventh O site, O is bonded in a distorted trigonal non-coplanar geometry to two Mg and one Si atom. In the twelfth O site, O is bonded in a 4-coordinate geometry to three Mg and one O atom. The O–O bond length is 1.52 Å. In the thirteenth O site, O is bonded to three Mg and one Si atom to form a mixture of distorted edge and corner-sharing OMg3Si tetrahedra. In the fourteenth O site, O is bonded in a rectangular see-saw-like geometry to three Mg and one Si atom. In the fifteenth O site, O is bonded in a distorted trigonal non-coplanar geometry to two Mg and one Si atom. In the sixteenth O site, O is bonded in a distorted bent 150 degrees geometry to two Si atoms.