Materials Data on Mg6CrSiO8 by Materials Project

Abstract

Mg6CrSiO8 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 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 (2.12 Å) and four longer (2.14 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 CrO6 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 (2.10 Å) and four longer (2.14 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 CrO6 octahedra, edges with two equivalent SiO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are five shorter (2.14 Å) and one longer (2.33 Å) Mg–O bond lengths. Cr is bonded to six O atoms to form CrO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with four equivalent CrO6 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 (2.14 Å) and two longer (2.36 Å) Cr–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 CrO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.14 Å) and two longer (2.34 Å) Si–O bond lengths. There are five 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 equivalent OMg5Si octahedra and edges with twelve OMg5Cr octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second O site, O is bonded to five Mg and one Cr atom to form OMg5Cr octahedra that share corners with six equivalent OMg5Cr octahedra and edges with twelve OMg5Si octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the third O site, O is bonded to two equivalent Mg, two equivalent Cr, and two equivalent Si atoms to form OMg2Cr2Si2 octahedra that share corners with six OMg2Cr2Si2 octahedra and edges with twelve OMg5Si 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 OMg2Cr2Si2 octahedra and edges with twelve OMg5Si octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O site, O is bonded to two equivalent Mg, two equivalent Cr, and two equivalent Si atoms to form OMg2Cr2Si2 octahedra that share corners with six OMg6 octahedra and edges with twelve OMg5Si octahedra. The corner-sharing octahedral tilt angles are 0°. Both O–Mg bond lengths are 2.33 Å.