Materials Data on EuAlGe2O7 by Materials Project

Abstract

EuAlGe2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Eu3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Eu–O bond distances ranging from 2.34–2.82 Å. Al3+ is bonded to five O2- atoms to form AlO5 trigonal bipyramids that share corners with five GeO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.80–1.95 Å. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one GeO4 tetrahedra and corners with two equivalent AlO5 trigonal bipyramids. There are a spread of Ge–O bond distances ranging from 1.73–1.79 Å. In the second Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one GeO4 tetrahedra and corners with three equivalent AlO5 trigonal bipyramids. There are a spread of Ge–O bond distances ranging from 1.76–1.82 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Eu3+, one Al3+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Eu3+, one Al3+, and one Ge4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Eu3+, one Al3+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Eu3+, one Al3+, and one Ge4+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Eu3+ and one Ge4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Eu3+, one Al3+, and one Ge4+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Eu3+ and two Ge4+ atoms.