Materials Data on LaAlGe2O7 by Materials Project

Abstract

LaAlGe2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. La3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of La–O bond distances ranging from 2.40–2.79 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 1.81–1.96 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 1.73–1.81 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 is three shorter (1.77 Å) and one longer (1.84 Å) Ge–O bond length. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one La3+, one Al3+, and one Ge4+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent La3+, one Al3+, and one Ge4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one La3+, one Al3+, and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one La3+, one Al3+, and one Ge4+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent La3+ and one Ge4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one La3+, one Al3+, and one Ge4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one La3+ and two Ge4+ atoms.