Materials Data on Eu2Mn(GeO3)4 by Materials Project

Abstract

Eu2MnGe4O12 crystallizes in the orthorhombic Cmme space group. The structure is three-dimensional. there are two inequivalent Eu3+ sites. In the first Eu3+ site, Eu3+ is bonded to six O2- atoms to form EuO6 octahedra that share corners with eight equivalent GeO4 tetrahedra. There are four shorter (2.33 Å) and two longer (2.54 Å) Eu–O bond lengths. In the second Eu3+ site, Eu3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.42 Å) and four longer (2.51 Å) Eu–O bond lengths. Mn2+ is bonded to six O2- atoms to form MnO6 octahedra that share corners with eight equivalent GeO4 tetrahedra. There are four shorter (2.04 Å) and two longer (2.50 Å) Mn–O bond lengths. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent EuO6 octahedra, corners with two equivalent MnO6 octahedra, and corners with two equivalent GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 46–70°. There are a spread of Ge–O bond distances ranging from 1.74–1.84 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Mn2+ and two equivalent Ge4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Eu3+ and two equivalent Ge4+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Eu3+, one Mn2+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Eu3+ and one Ge4+ atom.