Materials Data on Ba2GeO4 by Materials Project

Abstract

Ba2GeO4 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to six O2- atoms to form BaO6 octahedra that share corners with four equivalent BaO6 pentagonal pyramids, corners with two equivalent GeO4 tetrahedra, edges with two equivalent BaO6 octahedra, edges with two equivalent BaO6 pentagonal pyramids, and edges with two equivalent GeO4 tetrahedra. There are a spread of Ba–O bond distances ranging from 2.66–2.77 Å. In the second Ba2+ site, Ba2+ is bonded to six O2- atoms to form distorted BaO6 pentagonal pyramids that share corners with four equivalent BaO6 octahedra, corners with four equivalent BaO6 pentagonal pyramids, corners with four equivalent GeO4 tetrahedra, edges with two equivalent BaO6 octahedra, and an edgeedge with one GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 65–76°. There are a spread of Ba–O bond distances ranging from 2.64–2.80 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent BaO6 octahedra, corners with four equivalent BaO6 pentagonal pyramids, edges with two equivalent BaO6 octahedra, and an edgeedge with one BaO6 pentagonal pyramid. The corner-sharing octahedral tilt angles are 57°. There are a spread of Ge–O bond distances ranging from 1.78–1.81 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Ba2+ and one Ge4+ atom. In the second O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Ba2+ and one Ge4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Ba2+ and one Ge4+ atom.