DOI: 10.17188/1654695
title: Materials Data on LiMg6CrO8 by Materials Project

description: LiMg6CrO8 is Caswellsilverite-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent CrO6 octahedra, corners with four equivalent LiO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.11 Å) and two longer (2.32 Å) Li–O bond lengths. There are three inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with four equivalent LiO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.11 Å) and two longer (2.19 Å) Mg–O bond lengths. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with four equivalent CrO6 octahedra, and edges with eight equivalent MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Mg–O bond lengths are 2.11 Å. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, edges with two equivalent LiO6 octahedra, edges with two equivalent CrO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–16°. There are a spread of Mg–O bond distances ranging from 2.03–2.27 Å. Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four equivalent CrO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (1.98 Å) and four longer (2.11 Å) Cr–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to one Li1+, four equivalent Mg2+, and one Cr3+ atom to form OLiMg4Cr octahedra that share corners with six equivalent OLiMg4Cr octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–16°. In the second O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OLiMg4Cr octahedra. The corner-sharing octahedra tilt angles range from 0–9°. In the third O2- site, O2- is bonded to two equivalent Li1+ and four Mg2+ atoms to form OLi2Mg4 octahedra that share corners with six OLi2Mg4 octahedra and edges with twelve OLiMg4Cr octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O2- site, O2- is bonded to four Mg2+ and two equivalent Cr3+ atoms to form OMg4Cr2 octahedra that share corners with six OLi2Mg4 octahedra and edges with twelve OLiMg4Cr octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O2- site, O2- is bonded to two equivalent Li1+ and four Mg2+ atoms to form OLi2Mg4 octahedra that share corners with six OMg4Cr2 octahedra and edges with twelve OLiMg4Cr octahedra. The corner-sharing octahedral tilt angles are 0°. Both O–Mg bond lengths are 2.03 Å.