Materials Data on Ca2GeO4 by Materials Project

Abstract

Ca2GeO4 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a distorted single-bond geometry to ten O2- atoms. There are a spread of Ca–O bond distances ranging from 2.08–2.94 Å. In the second Ca2+ site, Ca2+ is bonded to six equivalent O2- atoms to form CaO6 octahedra that share corners with six equivalent GeO4 tetrahedra. All Ca–O bond lengths are 2.23 Å. In the third Ca2+ site, Ca2+ is bonded in a distorted hexagonal planar geometry to six equivalent O2- atoms. All Ca–O bond lengths are 2.67 Å. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with three equivalent CaO6 octahedra. The corner-sharing octahedral tilt angles are 14°. There is one shorter (1.71 Å) and three longer (1.78 Å) Ge–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Ca2+ and one Ge4+ atom. In the second O2- site, O2- is bonded in a 6-coordinate geometry to five Ca2+ and one Ge4+ atom.