DOI: 10.17188/1746865
title: Materials Data on Mg6CuSiO8 by Materials Project

description: Mg6CuSiO8 is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are three 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 CuO6 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 (2.04 Å) and four longer (2.13 Å) Mg–O bond lengths. 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 four shorter (2.13 Å) and two longer (2.24 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 six equivalent MgO6 octahedra, edges with two equivalent CuO6 octahedra, edges with two equivalent SiO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of Mg–O bond distances ranging from 2.13–2.18 Å. Cu is bonded to six O atoms to form CuO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with four equivalent CuO6 octahedra, edges with four equivalent SiO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.13 Å) and two longer (2.31 Å) Cu–O bond lengths. Si is bonded to six O atoms to form SiO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with four equivalent SiO6 octahedra, edges with four equivalent CuO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.11 Å) and four longer (2.13 Å) Si–O bond lengths. There are six inequivalent O sites. In the first O site, O is bonded to five Mg and one Cu atom to form OMg5Cu octahedra that share corners with six equivalent OMg5Cu octahedra and edges with twelve OMg5Si octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the second O site, O is bonded to five Mg and one Si atom to form OMg5Si octahedra that share corners with six equivalent OMg5Si octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the third O site, O is bonded to two equivalent Mg, two equivalent Cu, and two equivalent Si atoms to form OMg2Cu2Si2 octahedra that share corners with six OMg2Cu2Si2 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg2Cu2Si2 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O site, O is bonded to two equivalent Mg, two equivalent Cu, and two equivalent Si atoms to form OMg2Cu2Si2 octahedra that share corners with six OMg2Cu2Si2 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedral tilt angles are 0°. Both O–Mg bond lengths are 2.18 Å. In the sixth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg2Cu2Si2 octahedra and edges with twelve OMg5Cu octahedra. The corner-sharing octahedral tilt angles are 0°. Both O–Mg bond lengths are 2.17 Å.