Materials Data on CaLu2(GeO3)4 by Materials Project

Abstract

CaLu2(GeO3)4 crystallizes in the orthorhombic Cmme space group. The structure is three-dimensional. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with eight equivalent GeO4 tetrahedra. There are four shorter (2.29 Å) and two longer (2.55 Å) Ca–O bond lengths. There are two inequivalent Lu3+ sites. In the first Lu3+ site, Lu3+ is bonded to six O2- atoms to form LuO6 octahedra that share corners with eight equivalent GeO4 tetrahedra. There are four shorter (2.16 Å) and two longer (2.40 Å) Lu–O bond lengths. In the second Lu3+ site, Lu3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.28 Å) and four longer (2.39 Å) Lu–O bond lengths. Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share corners with two equivalent CaO6 octahedra, corners with two equivalent LuO6 octahedra, and corners with two equivalent GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–71°. There are a spread of Ge–O bond distances ranging from 1.73–1.85 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Ca2+ and two equivalent Ge4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Lu3+ and two equivalent Ge4+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ca2+, one Lu3+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Lu3+ and one Ge4+ atom.