Materials Data on CaGe(PO4)2 by Materials Project

CaGe(PO4)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.41–2.92 Å. Ge4+ is bonded to six O2- atoms to form GeO6 octahedra that share corners with six equivalent PO4 tetrahedra. There is two shorter (1.84 Å) and four longer (1.94 Å) Ge–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three equivalent GeO6 octahedra. The corner-sharing octahedra tilt angles range from 41–48°. There are a spread of P–O bond distances ranging from 1.51–1.58 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Ge4+, and one P5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Ge4+, and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ge4+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+ and one P5+ atom.