DOI: 10.17188/1653535
title: Materials Data on Mg30SiCO32 by Materials Project

description: Mg30SiO32C crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional and consists of one methane molecule and one Mg30SiO32 framework. In the Mg30SiO32 framework, there are eight inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent SiO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.09–2.27 Å. In the second Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.00–2.21 Å. In the third Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Mg–O bond lengths are 2.14 Å. In the fourth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.11 Å) and two longer (2.18 Å) Mg–O bond lengths. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one SiO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 3–31°. There are a spread of Mg–O bond distances ranging from 2.09–2.24 Å. In the sixth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Mg–O bond distances ranging from 2.10–2.17 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one SiO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are four shorter (2.12 Å) and two longer (2.16 Å) Mg–O bond lengths. In the eighth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of Mg–O bond distances ranging from 2.10–2.16 Å. Si is bonded to six O atoms to form SiO6 octahedra that share corners with four equivalent MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There is two shorter (1.67 Å) and four longer (1.96 Å) Si–O bond length. There are twelve inequivalent O sites. In the first O site, O is bonded to five Mg and one Si atom to form OMg5Si octahedra that share corners with four OMg5Si octahedra, corners with two equivalent OMg5 square pyramids, edges with ten OMg5Si octahedra, and edges with two equivalent OMg4Si trigonal bipyramids. The corner-sharing octahedra tilt angles range from 0–5°. In the second O site, O is bonded to five Mg atoms to form OMg5 square pyramids that share corners with four OMg5Si octahedra, corners with three equivalent OMg5 square pyramids, corners with two equivalent OMg4Si trigonal bipyramids, and edges with eight OMg6 octahedra. The corner-sharing octahedra tilt angles range from 2–5°. In the third O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. Both O–Mg bond lengths are 2.17 Å. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg5 square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the fifth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are two shorter (2.12 Å) and two longer (2.17 Å) O–Mg bond lengths. In the sixth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg5 square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg5 square pyramids. The corner-sharing octahedral tilt angles are 0°. All O–Mg bond lengths are 2.14 Å. In the seventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra, edges with nine OMg5Si octahedra, edges with two equivalent OMg5 square pyramids, and an edgeedge with one OMg4Si trigonal bipyramid. The corner-sharing octahedra tilt angles range from 1–5°. In the eighth O site, O is bonded to four equivalent Mg and one Si atom to form distorted OMg4Si trigonal bipyramids that share corners with four equivalent OMg6 octahedra, corners with four equivalent OMg5 square pyramids, a cornercorner with one OMg4Si trigonal bipyramid, and edges with eight OMg5Si octahedra. The corner-sharing octahedral tilt angles are 19°. In the ninth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg4Si trigonal bipyramids, edges with ten OMg5Si octahedra, and edges with two equivalent OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. In the tenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the eleventh O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. The O–Mg bond length is 2.09 Å. In the twelfth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are a spread of O–Mg bond distances ranging from 2.09–2.17 Å.