DOE OSTI2020
Y2O3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Y–O bond distances ranging from 2.25–2.59 Å. In the second Y3+ site, Y3+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing YO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Y–O bond distances ranging from 2.21–2.48 Å. In the third Y3+ site, Y3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Y–O bond distances ranging from 2.26–2.75 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to five Y3+ atoms to form distorted OY5 square pyramids that share corners with seven OY4 tetrahedra, corners with two equivalent OY4 trigonal pyramids, edges with two equivalent OY6 octahedra, edges with two equivalent OY5 square pyramids, edges with three OY4 tetrahedra, and edges with three equivalent OY4 trigonal pyramids. In the second O2- site, O2- is bonded to four Y3+ atoms to form OY4 tetrahedra that share a cornercorner with one OY6 octahedra, corners with five equivalent OY5 square pyramids, corners with four OY4 tetrahedra, corners with three equivalent OY4 trigonal pyramids, edges with two equivalent OY6 octahedra, an edgeedge with one OY5 square pyramid, and edges with two equivalent OY4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. In the third O2- site, O2- is bonded to four Y3+ atoms to form distorted OY4 trigonal pyramids that share a cornercorner with one OY6 octahedra, corners with two equivalent OY5 square pyramids, corners with nine OY4 tetrahedra, corners with two equivalent OY4 trigonal pyramids, edges with three equivalent OY5 square pyramids, and edges with two equivalent OY4 trigonal pyramids. The corner-sharing octahedral tilt angles are 37°. In the fourth O2- site, O2- is bonded to four Y3+ atoms to form distorted OY4 tetrahedra that share corners with two equivalent OY6 octahedra, corners with two equivalent OY5 square pyramids, corners with four OY4 tetrahedra, corners with six equivalent OY4 trigonal pyramids, an edgeedge with one OY6 octahedra, edges with two equivalent OY5 square pyramids, and an edgeedge with one OY4 tetrahedra. The corner-sharing octahedral tilt angles are 13°. In the fifth O2- site, O2- is bonded to six Y3+ atoms to form OY6 octahedra that share corners with six OY4 tetrahedra, corners with two equivalent OY4 trigonal pyramids, edges with two equivalent OY6 octahedra, edges with four equivalent OY5 square pyramids, and edges with six OY4 tetrahedra.