DOI: 10.17188/1318578
title: Materials Data on MgMn4O8 by Materials Project

description: MgMn4O8 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 MnO6 octahedra, edges with three MnO6 octahedra, edges with two equivalent MgO5 square pyramids, and a faceface with one MnO6 octahedra. The corner-sharing octahedra tilt angles range from 4–55°. There are a spread of Mg–O bond distances ranging from 2.06–2.13 Å. There are four inequivalent Mn+3.50+ sites. In the first Mn+3.50+ site, Mn+3.50+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four MnO6 octahedra, edges with four MnO6 octahedra, and edges with two equivalent MgO5 square pyramids. The corner-sharing octahedra tilt angles range from 49–52°. There are a spread of Mn–O bond distances ranging from 1.95–2.22 Å. In the second Mn+3.50+ site, Mn+3.50+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four MnO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with four MnO6 octahedra, and a faceface with one MgO5 square pyramid. The corner-sharing octahedra tilt angles range from 49–54°. There are a spread of Mn–O bond distances ranging from 1.91–2.18 Å. In the third Mn+3.50+ site, Mn+3.50+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four MnO6 octahedra, corners with two equivalent MgO5 square pyramids, and edges with four MnO6 octahedra. The corner-sharing octahedra tilt angles range from 51–52°. There are a spread of Mn–O bond distances ranging from 1.94–2.04 Å. In the fourth Mn+3.50+ site, Mn+3.50+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four MnO6 octahedra, corners with two equivalent MgO5 square pyramids, edges with four MnO6 octahedra, and an edgeedge with one MgO5 square pyramid. The corner-sharing octahedra tilt angles range from 51–54°. There are a spread of Mn–O bond distances ranging from 1.93–2.13 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to three Mn+3.50+ atoms. In the second O2- site, O2- is bonded in a trigonal planar geometry to three Mn+3.50+ atoms. In the third O2- site, O2- is bonded in a trigonal planar geometry to three Mn+3.50+ atoms. In the fourth O2- site, O2- is bonded to one Mg2+ and three Mn+3.50+ atoms to form OMgMn3 trigonal pyramids that share corners with two equivalent OMgMn3 trigonal pyramids, edges with two equivalent OMg2Mn3 square pyramids, and edges with two equivalent OMg2Mn3 trigonal bipyramids. In the fifth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Mn+3.50+ atoms. In the sixth O2- site, O2- is bonded to two equivalent Mg2+ and three Mn+3.50+ atoms to form distorted OMg2Mn3 trigonal bipyramids that share corners with two equivalent OMg2Mn3 square pyramids, an edgeedge with one OMg2Mn3 square pyramid, edges with two equivalent OMg2Mn3 trigonal bipyramids, and edges with two equivalent OMgMn3 trigonal pyramids. In the seventh O2- site, O2- is bonded to two equivalent Mg2+ and three Mn+3.50+ atoms to form OMg2Mn3 square pyramids that share corners with two equivalent OMg2Mn3 trigonal bipyramids, edges with two equivalent OMg2Mn3 square pyramids, an edgeedge with one OMg2Mn3 trigonal bipyramid, and edges with two equivalent OMgMn3 trigonal pyramids. In the eighth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Mn+3.50+ atoms.