Materials Data on HoCrGeO5 by Materials Project
HoCrGeO5 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.27–2.59 Å. Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with four equivalent GeO5 square pyramids and edges with two equivalent CrO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.98–2.01 Å. Ge4+ is bonded to five O2- atoms to form distorted GeO5 square pyramids that share corners with four equivalent CrO6 octahedra and an edgeedge with one GeO5 square pyramid. The corner-sharing octahedra tilt angles range from 48–55°. There are a spread of Ge–O bond distances ranging from 1.76–1.94 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+, one Cr3+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Cr3+ and one Ge4+ atom. In the third O2- site, O2- is bonded to two equivalent Ho3+ and two equivalent Cr3+ atoms to form a mixture of distorted edge and corner-sharing OHo2Cr2 trigonal pyramids. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+ and two equivalent Ge4+ atoms.