Materials Data on ErAlGeO5 by Materials Project

ErAlGeO5 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Er3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Er–O bond distances ranging from 2.28–2.50 Å. Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with four equivalent GeO5 square pyramids and edges with two equivalent AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.89–1.95 Å. Ge4+ is bonded to five O2- atoms to form distorted GeO5 square pyramids that share corners with four equivalent AlO6 octahedra and an edgeedge with one GeO5 square pyramid. The corner-sharing octahedra tilt angles range from 49–52°. There are a spread of Ge–O bond distances ranging from 1.77–1.93 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Er3+, one Al3+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Er3+ and two equivalent Al3+ atoms. In the third O2- site, O2- is bonded to two equivalent Er3+ and two equivalent Ge4+ atoms to form distorted edge-sharing OEr2Ge2 tetrahedra. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Al3+ and one Ge4+ atom.