Materials Data on Mn7GeO12 by Materials Project
Mn7GeO12 is Hausmannite-derived structured and crystallizes in the tetragonal I4_1/acd space group. The structure is three-dimensional. there are four inequivalent Mn+2.86+ sites. In the first Mn+2.86+ site, Mn+2.86+ is bonded to six O2- atoms to form distorted MnO6 octahedra that share corners with four MnO6 octahedra, corners with two equivalent GeO4 tetrahedra, and edges with four MnO6 octahedra. The corner-sharing octahedra tilt angles range from 54–61°. There are a spread of Mn–O bond distances ranging from 1.98–2.27 Å. In the second Mn+2.86+ site, Mn+2.86+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are four shorter (2.18 Å) and four longer (2.57 Å) Mn–O bond lengths. In the third Mn+2.86+ site, Mn+2.86+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four MnO6 octahedra, corners with two equivalent GeO4 tetrahedra, and edges with four MnO6 octahedra. The corner-sharing octahedra tilt angles range from 48–61°. There are a spread of Mn–O bond distances ranging from 1.90–2.31 Å. In the fourth Mn+2.86+ site, Mn+2.86+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four MnO6 octahedra, corners with two equivalent GeO4 tetrahedra, and edges with four MnO6 octahedra. The corner-sharing octahedra tilt angles range from 48–54°. There are a spread of Mn–O bond distances ranging from 1.98–2.26 Å. Ge4+ is bonded to four equivalent O2- atoms to form GeO4 tetrahedra that share corners with twelve MnO6 octahedra. The corner-sharing octahedra tilt angles range from 52–64°. All Ge–O bond lengths are 1.75 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to four Mn+2.86+ atoms. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Mn+2.86+ and one Ge4+ atom. In the third O2- site, O2- is bonded to four Mn+2.86+ atoms to form a mixture of distorted corner and edge-sharing OMn4 tetrahedra.