Materials Data on Mg6CrBO8 by Materials Project
Mg6CrBO8 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 a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.07 Å) and four longer (2.19 Å) Mg–O bond lengths. In the second 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 two shorter (2.07 Å) and four longer (2.19 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 octahedra tilt angles range from 0–30°. There are a spread of Mg–O bond distances ranging from 1.99–2.26 Å. Cr is bonded in a distorted square co-planar geometry to four equivalent O atoms. All Cr–O bond lengths are 2.19 Å. B is bonded in a linear geometry to six O atoms. There is two shorter (1.41 Å) and four longer (2.19 Å) B–O bond length. There are five inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to four equivalent Mg and one B atom. In the second O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with eight OMg4Cr2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the third O site, O is bonded to four Mg and two equivalent Cr atoms to form OMg4Cr2 octahedra that share corners with six OMg4Cr2 octahedra and edges with eight OMg6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fourth O site, O is bonded to four Mg and two equivalent B atoms to form distorted OMg4B2 octahedra that share corners with six OMg4Cr2 octahedra and edges with eight OMg6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the fifth O site, O is bonded to four Mg and two equivalent B atoms to form distorted OMg4B2 octahedra that share corners with six OMg4Cr2 octahedra and edges with eight OMg6 octahedra. The corner-sharing octahedral tilt angles are 0°. Both O–Mg bond lengths are 1.99 Å.