Materials Data on Ca2MnO4 by Materials Project
Ca2MnO4 crystallizes in the tetragonal I4_1/acd 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 2.32–2.63 Å. Mn4+ is bonded to six O2- atoms to form corner-sharing MnO6 octahedra. The corner-sharing octahedral tilt angles are 25°. There is four shorter (1.90 Å) and two longer (1.97 Å) Mn–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to five equivalent Ca2+ and one Mn4+ atom to form a mixture of distorted edge and corner-sharing OCa5Mn octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent Mn4+ atoms.