DOI: 10.17188/1653595
title: Materials Data on CsMg6SiO8 by Materials Project

description: CsMg6SiO8 crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. Cs is bonded to six O atoms to form CsO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with four equivalent CsO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Cs–O bond distances ranging from 2.25–2.76 Å. There are four inequivalent Mg sites. In the first 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 2.13–2.30 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent CsO6 octahedra, corners with four equivalent 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 1.99–2.30 Å. In the third Mg site, Mg is bonded to six O atoms to form distorted MgO6 octahedra that share corners with six equivalent MgO6 octahedra, edges with two equivalent CsO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.07–2.68 Å. In the fourth Mg site, Mg is bonded to six O atoms to form distorted MgO6 octahedra that share corners with six equivalent MgO6 octahedra, edges with two equivalent CsO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.06–2.69 Å. Si is bonded in a square co-planar geometry to four O atoms. There are two shorter (2.25 Å) and two longer (2.30 Å) Si–O bond lengths. There are seven inequivalent O sites. In the first O site, O is bonded to five Mg atoms to form OMg5 square pyramids that share corners with four OCs2Mg2Si2 octahedra, corners with five OMg5 square pyramids, and edges with eight OCsMg5 octahedra. The corner-sharing octahedral tilt angles are 92°. In the second O site, O is bonded to five Mg atoms to form OMg5 square pyramids that share corners with four OCs2Mg2Si2 octahedra, corners with five OMg5 square pyramids, and edges with eight OCsMg5 octahedra. The corner-sharing octahedral tilt angles are 92°. There are two shorter (2.25 Å) and two longer (2.30 Å) O–Mg bond lengths. In the third O site, O is bonded to one Cs and five Mg atoms to form OCsMg5 octahedra that share corners with six equivalent OCsMg5 octahedra, edges with eight OCs2Mg2Si2 octahedra, and edges with four equivalent OMg5 square pyramids. The corner-sharing octahedra tilt angles range from 0–4°. In the fourth O site, O is bonded to two equivalent Cs, two equivalent Mg, and two equivalent Si atoms to form OCs2Mg2Si2 octahedra that share corners with six OCs2Mg2Si2 octahedra, corners with four OMg5 square pyramids, and edges with eight OCsMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OCs2Mg2Si2 octahedra, edges with eight OCsMg5 octahedra, and edges with four OMg5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the sixth O site, O is bonded to two equivalent Cs, two equivalent Mg, and two equivalent Si atoms to form OCs2Mg2Si2 octahedra that share corners with six OCs2Mg2Si2 octahedra, corners with four OMg5 square pyramids, and edges with eight OCsMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OCs2Mg2Si2 octahedra, edges with eight OCsMg5 octahedra, and edges with four OMg5 square pyramids. The corner-sharing octahedral tilt angles are 0°.