DOE OSTI2020
TmYO3 crystallizes in the hexagonal P6_3cm space group. The structure is three-dimensional. Tm3+ is bonded to five O2- atoms to form corner-sharing TmO5 trigonal bipyramids. There are a spread of Tm–O bond distances ranging from 2.15–2.19 Å. There are two 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 2.36–2.67 Å. In the second 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 2.32–2.55 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to one Tm3+ and three Y3+ atoms to form OY3Tm tetrahedra that share corners with ten OY3Tm tetrahedra, corners with two equivalent OYTm3 trigonal pyramids, edges with three equivalent OY3Tm tetrahedra, and edges with two equivalent OYTm3 trigonal pyramids. In the second O2- site, O2- is bonded to one Tm3+ and three Y3+ atoms to form distorted OY3Tm tetrahedra that share corners with ten OY3Tm tetrahedra, corners with four equivalent OYTm3 trigonal pyramids, edges with three equivalent OY3Tm tetrahedra, and an edgeedge with one OYTm3 trigonal pyramid. In the third O2- site, O2- is bonded to three equivalent Tm3+ and one Y3+ atom to form distorted OYTm3 trigonal pyramids that share corners with six equivalent OY3Tm tetrahedra, corners with six OYTm3 trigonal pyramids, and edges with three equivalent OY3Tm tetrahedra. In the fourth O2- site, O2- is bonded to three equivalent Tm3+ and one Y3+ atom to form distorted OYTm3 trigonal pyramids that share corners with six equivalent OY3Tm tetrahedra, corners with six equivalent OYTm3 trigonal pyramids, and edges with three equivalent OY3Tm tetrahedra.