Materials Data on MgV4O8 by Materials Project
MgV4O8 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Mg2+ is bonded to five O2- atoms to form MgO5 square pyramids that share corners with six VO6 octahedra, edges with three VO6 octahedra, edges with two equivalent MgO5 square pyramids, and a faceface with one VO6 octahedra. The corner-sharing octahedra tilt angles range from 5–56°. There are a spread of Mg–O bond distances ranging from 2.05–2.11 Å. There are four inequivalent V+3.50+ sites. In the first V+3.50+ site, V+3.50+ is bonded to six O2- atoms to form distorted VO6 octahedra that share corners with four VO6 octahedra, edges with four VO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 48–50°. There are a spread of V–O bond distances ranging from 1.80–2.30 Å. In the second V+3.50+ site, V+3.50+ is bonded to six O2- atoms to form distorted VO6 octahedra that share corners with four VO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with four VO6 octahedra, and a faceface with one MgO5 square pyramid. The corner-sharing octahedra tilt angles range from 48–53°. There are a spread of V–O bond distances ranging from 1.80–2.20 Å. In the third V+3.50+ site, V+3.50+ is bonded to six O2- atoms to form VO6 octahedra that share corners with four VO6 octahedra, corners with two equivalent MgO5 square pyramids, and edges with four VO6 octahedra. The corner-sharing octahedral tilt angles are 50°. There are a spread of V–O bond distances ranging from 1.91–2.10 Å. In the fourth V+3.50+ site, V+3.50+ is bonded to six O2- atoms to form VO6 octahedra that share corners with four VO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with four VO6 octahedra, and an edgeedge with one MgO5 square pyramid. The corner-sharing octahedra tilt angles range from 50–53°. There are a spread of V–O bond distances ranging from 1.97–2.17 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V+3.50+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three V+3.50+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to three V+3.50+ atoms. In the fourth O2- site, O2- is bonded to one Mg2+ and three V+3.50+ atoms to form OMgV3 trigonal pyramids that share corners with two equivalent OMgV3 trigonal pyramids, edges with two equivalent OMg2V3 square pyramids, and edges with two equivalent OMg2V3 trigonal bipyramids. In the fifth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three V+3.50+ atoms. In the sixth O2- site, O2- is bonded to two equivalent Mg2+ and three V+3.50+ atoms to form distorted OMg2V3 trigonal bipyramids that share corners with two equivalent OMg2V3 square pyramids, an edgeedge with one OMg2V3 square pyramid, edges with two equivalent OMg2V3 trigonal bipyramids, and edges with two equivalent OMgV3 trigonal pyramids. In the seventh O2- site, O2- is bonded to two equivalent Mg2+ and three V+3.50+ atoms to form OMg2V3 square pyramids that share corners with two equivalent OMg2V3 trigonal bipyramids, edges with two equivalent OMg2V3 square pyramids, an edgeedge with one OMg2V3 trigonal bipyramid, and edges with two equivalent OMgV3 trigonal pyramids. In the eighth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three V+3.50+ atoms.