DOI: 10.17188/1673073
title: Materials Data on Mg30SiCO32 by Materials Project

description: Mg30SiCO32 is Molybdenum Carbide MAX Phase-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. 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 MgO6 octahedra, corners with two equivalent SiO6 octahedra, corners with two equivalent CO6 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 2.06–2.14 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent SiO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.06 Å) and four longer (2.15 Å) Mg–O bond lengths. 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°. There are four shorter (2.12 Å) and two longer (2.14 Å) Mg–O bond lengths. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent CO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.12 Å) and four longer (2.13 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, an edgeedge with one CO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. There are a spread of Mg–O bond distances ranging from 2.11–2.17 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 0–1°. There are two shorter (2.13 Å) and four longer (2.14 Å) Mg–O bond lengths. 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 0–4°. There are a spread of Mg–O bond distances ranging from 2.12–2.15 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one CO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are a spread of Mg–O bond distances ranging from 2.12–2.15 Å. Si is bonded to six O atoms to form SiO6 octahedra that share corners with six MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Si–O bond lengths are 2.21 Å. C is bonded to six O atoms to form distorted CO6 octahedra that share corners with six MgO6 octahedra and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. All C–O bond lengths are 2.15 Å. 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 six OMg5Si octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg5Si octahedra, corners with two equivalent OMg5C square pyramids, edges with ten OMg6 octahedra, and edges with two OMg5C square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. In the third O site, O is bonded to five Mg and one C atom to form distorted OMg5C square pyramids that share corners with four equivalent OMg6 octahedra, corners with two equivalent OMg5C square pyramids, edges with eight OMg6 octahedra, and edges with four OMg5C square pyramids. The corner-sharing octahedral tilt angles are 1°. In the fourth 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, and edges with three OMg5C square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. In the fifth 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 OMg5C square pyramids, edges with ten OMg5Si octahedra, and edges with two OMg5C square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. In the sixth 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 OMg5C square pyramids, edges with ten OMg5Si octahedra, and edges with two OMg5C square pyramids. The corner-sharing octahedra tilt angles range from 0–2°. There are two shorter (2.14 Å) and two longer (2.17 Å) O–Mg bond lengths. In the seventh O site, O is bonded to five Mg and one C atom to form distorted OMg5C square pyramids that share corners with four OMg5Si octahedra, corners with two equivalent OMg5C square pyramids, edges with eight OMg6 octahedra, and edges with four OMg5C square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. The O–Mg bond length is 2.12 Å. In the eighth O site, O is bonded to five Mg and one C atom to form distorted OMg5C square pyramids that share corners with four OMg5Si octahedra, corners with two equivalent OMg5C square pyramids, edges with eight OMg6 octahedra, and edges with four OMg5C square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. There are two shorter (2.11 Å) and three longer (2.12 Å) O–Mg bond lengths. In the ninth 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 0–2°. In the tenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with four OMg6 octahedra, corners with two equivalent OMg5C square pyramids, edges with ten OMg6 octahedra, and edges with two equivalent OMg5C square pyramids. The corner-sharing octahedral tilt angles are 0°. In the eleventh O site, O is bonded to five Mg and one C atom to form distorted OMg5C square pyramids that share corners with four OMg5Si octahedra, corners with two equivalent OMg5C square pyramids, edges with eight OMg6 octahedra, and edges with four OMg5C square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. Both O–Mg bond lengths are 2.12 Å. In the twelfth O site, O is bonded to five Mg and one C atom to form distorted OMg5C square pyramids that share corners with four OMg5Si octahedra, corners with two equivalent OMg5C square pyramids, edges with eight OMg6 octahedra, and edges with four OMg5C square pyramids. The corner-sharing octahedra tilt angles range from 0–1°. There are two shorter (2.11 Å) and two longer (2.12 Å) O–Mg bond lengths.