Materials Data on La2Cr2O5 by Materials Project

Abstract

La2Cr2O5 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are four inequivalent La3+ sites. In the first 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 2.39–2.86 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 2.40–2.88 Å. In the third 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 2.40–2.88 Å. In the fourth 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 2.39–2.86 Å. There are four inequivalent Cr2+ sites. In the first Cr2+ site, Cr2+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with four equivalent CrO6 octahedra and corners with two CrO4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 25–26°. There are two shorter (2.01 Å) and four longer (2.02 Å) Cr–O bond lengths. In the second Cr2+ site, Cr2+ is bonded to four O2- atoms to form CrO4 trigonal pyramids that share corners with two equivalent CrO6 octahedra and corners with two equivalent CrO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 23°. There are a spread of Cr–O bond distances ranging from 2.01–2.15 Å. In the third Cr2+ site, Cr2+ is bonded to four O2- atoms to form distorted CrO4 trigonal pyramids that share corners with two equivalent CrO6 octahedra and corners with two equivalent CrO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 23°. There are a spread of Cr–O bond distances ranging from 2.02–2.14 Å. In the fourth Cr2+ site, Cr2+ is bonded to four O2- atoms to form CrO4 trigonal pyramids that share corners with two equivalent CrO6 octahedra and corners with two equivalent CrO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 23°. There are a spread of Cr–O bond distances ranging from 2.01–2.15 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to two La3+ and two equivalent Cr2+ atoms to form distorted OLa2Cr2 trigonal pyramids that share corners with two equivalent OLa4Cr2 octahedra, corners with four OLa2Cr2 trigonal pyramids, an edgeedge with one OLa4Cr2 octahedra, and edges with two equivalent OLa2Cr2 trigonal pyramids. The corner-sharing octahedral tilt angles are 60°. In the second O2- site, O2- is bonded to two La3+ and two equivalent Cr2+ atoms to form distorted OLa2Cr2 trigonal pyramids that share corners with two equivalent OLa4Cr2 octahedra, corners with four OLa2Cr2 trigonal pyramids, an edgeedge with one OLa4Cr2 octahedra, and edges with two equivalent OLa2Cr2 trigonal pyramids. The corner-sharing octahedra tilt angles range from 60–61°. In the third O2- site, O2- is bonded to two La3+ and two equivalent Cr2+ atoms to form distorted OLa2Cr2 trigonal pyramids that share corners with two equivalent OLa4Cr2 octahedra, corners with four OLa2Cr2 trigonal pyramids, an edgeedge with one OLa4Cr2 octahedra, and edges with two equivalent OLa2Cr2 trigonal pyramids. The corner-sharing octahedra tilt angles range from 60–61°. In the fourth O2- site, O2- is bonded in a 5-coordinate geometry to three La3+ and two Cr2+ atoms. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to three La3+ and two Cr2+ atoms. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to three La3+ and two Cr2+ atoms. The O–Cr bond length is 2.01 Å. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to three La3+ and two Cr2+ atoms. The O–Cr bond length is 2.02 Å. In the eighth O2- site, O2- is bonded to four La3+ and two Cr2+ atoms to form distorted OLa4Cr2 octahedra that share corners with four OLa2Cr2 trigonal pyramids, edges with two equivalent OLa2Cr2 trigonal pyramids, and faces with two equivalent OLa4Cr2 octahedra. In the ninth O2- site, O2- is bonded to four La3+ and two Cr2+ atoms to form distorted OLa4Cr2 octahedra that share corners with four equivalent OLa2Cr2 trigonal pyramids, edges with two OLa2Cr2 trigonal pyramids, and faces with two equivalent OLa4Cr2 octahedra.