Materials Data on CaMn4O8 by Materials Project

CaMn4O8 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.19–2.84 Å. There are three inequivalent Mn+3.50+ sites. In the first Mn+3.50+ site, Mn+3.50+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Mn–O bond distances ranging from 1.91–1.96 Å. In the second Mn+3.50+ site, Mn+3.50+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MnO6 octahedra. The corner-sharing octahedra tilt angles range from 53–56°. There are a spread of Mn–O bond distances ranging from 1.94–2.07 Å. In the third Mn+3.50+ site, Mn+3.50+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing MnO6 octahedra. The corner-sharing octahedra tilt angles range from 48–56°. There are a spread of Mn–O bond distances ranging from 1.94–2.55 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and three Mn+3.50+ atoms to form distorted corner-sharing OCaMn3 trigonal pyramids. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+ and three Mn+3.50+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+ and three Mn+3.50+ atoms. In the fourth O2- site, O2- is bonded to one Ca2+ and three Mn+3.50+ atoms to form distorted corner-sharing OCaMn3 tetrahedra. In the fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Mn+3.50+ atoms. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ca2+ and three Mn+3.50+ atoms.