Materials Data on MgMnGeO4 by Materials Project

MgMnGeO4 is Hausmannite-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with four equivalent MnO6 octahedra, corners with two equivalent GeO4 tetrahedra, edges with two equivalent MgO6 octahedra, edges with two equivalent MnO6 octahedra, and edges with two equivalent GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–59°. There are four shorter (2.12 Å) and two longer (2.20 Å) Mg–O bond lengths. Mn2+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with four equivalent MgO6 octahedra, corners with four equivalent MnO6 octahedra, corners with four equivalent GeO4 tetrahedra, edges with two equivalent MgO6 octahedra, and an edgeedge with one GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–59°. There are three shorter (2.17 Å) and three longer (2.34 Å) Mn–O bond lengths. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent MgO6 octahedra, corners with four equivalent MnO6 octahedra, an edgeedge with one MnO6 octahedra, and edges with two equivalent MgO6 octahedra. The corner-sharing octahedra tilt angles range from 58–64°. There are a spread of Ge–O bond distances ranging from 1.76–1.81 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a rectangular see-saw-like geometry to two equivalent Mg2+, one Mn2+, and one Ge4+ atom. In the second O2- site, O2- is bonded to two equivalent Mg2+, one Mn2+, and one Ge4+ atom to form distorted corner-sharing OMg2MnGe tetrahedra. In the third O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Mg2+, two equivalent Mn2+, and one Ge4+ atom.