DOI: 10.17188/1299302
title: Materials Data on La4Ga2O9 by Materials Project

description: La4Ga2O9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are four inequivalent La3+ sites. In the first La3+ site, La3+ is bonded to six O2- atoms to form LaO6 octahedra that share corners with three equivalent GaO4 tetrahedra, corners with two equivalent GaO4 trigonal pyramids, and edges with two equivalent LaO7 hexagonal pyramids. There are a spread of La–O bond distances ranging from 2.35–2.52 Å. In the second La3+ site, La3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of La–O bond distances ranging from 2.43–2.86 Å. In the third La3+ site, La3+ is bonded in a 8-coordinate geometry to seven O2- atoms. There are a spread of La–O bond distances ranging from 2.41–2.84 Å. In the fourth La3+ site, La3+ is bonded to seven O2- atoms to form distorted LaO7 hexagonal pyramids that share a cornercorner with one GaO4 tetrahedra, corners with two equivalent GaO4 trigonal pyramids, edges with two equivalent LaO6 octahedra, an edgeedge with one GaO4 tetrahedra, and an edgeedge with one GaO4 trigonal pyramid. There are a spread of La–O bond distances ranging from 2.38–2.67 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share a cornercorner with one LaO7 hexagonal pyramid, corners with three equivalent LaO6 octahedra, a cornercorner with one GaO4 trigonal pyramid, and an edgeedge with one LaO7 hexagonal pyramid. The corner-sharing octahedra tilt angles range from 49–64°. There are a spread of Ga–O bond distances ranging from 1.84–1.89 Å. In the second Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 trigonal pyramids that share corners with two equivalent LaO7 hexagonal pyramids, corners with two equivalent LaO6 octahedra, a cornercorner with one GaO4 tetrahedra, and an edgeedge with one LaO7 hexagonal pyramid. The corner-sharing octahedra tilt angles range from 40–53°. There are a spread of Ga–O bond distances ranging from 1.85–1.90 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three La3+ and one Ga3+ atom. In the second O2- site, O2- is bonded to two La3+ and two Ga3+ atoms to form a mixture of distorted edge and corner-sharing OLa2Ga2 tetrahedra. In the third O2- site, O2- is bonded to four La3+ atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three La3+ and one Ga3+ atom. In the fifth O2- site, O2- is bonded to four La3+ atoms to form OLa4 tetrahedra that share corners with five OLa2Ga2 tetrahedra and edges with two OLa4 tetrahedra. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three La3+ and one Ga3+ atom. In the seventh O2- site, O2- is bonded to three La3+ and one Ga3+ atom to form a mixture of distorted edge and corner-sharing OLa3Ga tetrahedra. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three La3+ and one Ga3+ atom. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to two La3+ and one Ga3+ atom.