DOI: 10.17188/1717290
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 2.03–2.14 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 four shorter (2.09 Å) and two longer (2.13 Å) Mg–O bond lengths. 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 six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.13 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 five MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.02–2.16 Å. In the fifth Mg site, Mg is bonded to six O atoms to form distorted MgO6 octahedra that share corners with four SiO4 tetrahedra, edges with three MgO6 octahedra, and edges with two equivalent SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.41 Å. In the sixth 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 2.04–2.11 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 five MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.15 Å. In the eighth 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 two shorter (2.09 Å) and four longer (2.10 Å) Mg–O bond lengths. In the ninth Mg site, Mg is bonded to six O atoms to form distorted MgO6 octahedra that share corners with four SiO4 tetrahedra, edges with three MgO6 octahedra, and edges with two equivalent SiO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.04–2.47 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°. There is three shorter (1.64 Å) and one longer (1.65 Å) Si–O bond length. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with four 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 four MgO6 octahedra, corners with two equivalent SiO4 tetrahedra, and an edgeedge with one MgO6 octahedra. The corner-sharing octahedra tilt angles range from 34–60°. 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 four MgO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–62°. There is three shorter (1.63 Å) and one longer (1.65 Å) Si–O bond length. In the fifth Si site, Si is bonded to four O 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 33–59°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. There are sixteen inequivalent O sites. In the first O site, O is bonded in a 3-coordinate geometry to one Mg and 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 in a distorted rectangular see-saw-like geometry to three Mg and one Si atom. 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 T-shaped geometry to two Mg and one Si atom. In the twelfth O site, O is bonded in a trigonal non-coplanar geometry to three Mg atoms. In the thirteenth O site, O is bonded in a distorted rectangular see-saw-like geometry to three Mg and one Si atom. 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 T-shaped geometry to two Mg and one Si atom. In the sixteenth O site, O is bonded in a bent 150 degrees geometry to two Si atoms.