DOE OSTI2020
La2O3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three 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 2.39–2.87 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 2.38–2.85 Å. In the third La3+ site, La3+ is bonded to six O2- atoms to form a mixture of distorted corner and edge-sharing LaO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of La–O bond distances ranging from 2.36–2.67 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four La3+ atoms to form distorted OLa4 trigonal pyramids that share a cornercorner with one OLa6 octahedra, corners with two equivalent OLa5 square pyramids, corners with nine OLa4 tetrahedra, corners with two equivalent OLa4 trigonal pyramids, edges with three equivalent OLa5 square pyramids, and edges with two equivalent OLa4 trigonal pyramids. The corner-sharing octahedral tilt angles are 34°. In the second O2- site, O2- is bonded to five La3+ atoms to form distorted OLa5 square pyramids that share corners with seven OLa4 tetrahedra, corners with two equivalent OLa4 trigonal pyramids, edges with two equivalent OLa6 octahedra, edges with two equivalent OLa5 square pyramids, edges with three OLa4 tetrahedra, and edges with three equivalent OLa4 trigonal pyramids. In the third O2- site, O2- is bonded to four La3+ atoms to form OLa4 tetrahedra that share corners with two equivalent OLa6 octahedra, corners with two equivalent OLa5 square pyramids, corners with four OLa4 tetrahedra, corners with six equivalent OLa4 trigonal pyramids, an edgeedge with one OLa6 octahedra, edges with two equivalent OLa5 square pyramids, and an edgeedge with one OLa4 tetrahedra. The corner-sharing octahedral tilt angles are 15°. In the fourth O2- site, O2- is bonded to four La3+ atoms to form OLa4 tetrahedra that share a cornercorner with one OLa6 octahedra, corners with five equivalent OLa5 square pyramids, corners with four OLa4 tetrahedra, corners with three equivalent OLa4 trigonal pyramids, edges with two equivalent OLa6 octahedra, an edgeedge with one OLa5 square pyramid, and edges with two equivalent OLa4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the fifth O2- site, O2- is bonded to six La3+ atoms to form OLa6 octahedra that share corners with six OLa4 tetrahedra, corners with two equivalent OLa4 trigonal pyramids, edges with two equivalent OLa6 octahedra, edges with four equivalent OLa5 square pyramids, and edges with six OLa4 tetrahedra.