DOI: 10.17188/1207407
title: Materials Data on Er10Ti6O27 by Materials Project

description: Er10Ti6O27 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are seven inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to seven O2- atoms to form distorted ErO7 pentagonal bipyramids that share a cornercorner with one ErO6 octahedra, a cornercorner with one TiO6 octahedra, a cornercorner with one ErO7 pentagonal bipyramid, an edgeedge with one TiO6 octahedra, and an edgeedge with one ErO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 52–71°. There are a spread of Er–O bond distances ranging from 2.17–2.41 Å. In the second Er3+ site, Er3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Er–O bond distances ranging from 2.13–2.36 Å. In the third Er3+ site, Er3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Er–O bond distances ranging from 2.15–2.46 Å. In the fourth Er3+ site, Er3+ is bonded in a 5-coordinate geometry to seven O2- atoms. There are a spread of Er–O bond distances ranging from 2.09–2.73 Å. In the fifth Er3+ site, Er3+ is bonded in a 3-coordinate geometry to five O2- atoms. There are a spread of Er–O bond distances ranging from 2.12–2.61 Å. In the sixth Er3+ site, Er3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Er–O bond distances ranging from 2.14–2.50 Å. In the seventh Er3+ site, Er3+ is bonded to six O2- atoms to form distorted ErO6 octahedra that share corners with two equivalent ErO7 pentagonal bipyramids and a cornercorner with one TiO5 trigonal bipyramid. There are a spread of Er–O bond distances ranging from 2.18–2.38 Å. There are five inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.87–2.26 Å. In the second Ti4+ site, Ti4+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ti–O bond distances ranging from 1.85–2.33 Å. In the third Ti4+ site, Ti4+ is bonded to five O2- atoms to form distorted TiO5 trigonal bipyramids that share a cornercorner with one ErO6 octahedra. The corner-sharing octahedral tilt angles are 64°. There is three shorter (1.89 Å) and two longer (2.06 Å) Ti–O bond length. In the fourth Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with two equivalent ErO7 pentagonal bipyramids and edges with two equivalent ErO7 pentagonal bipyramids. There are a spread of Ti–O bond distances ranging from 1.93–2.20 Å. In the fifth Ti4+ site, Ti4+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ti–O bond distances ranging from 1.89–2.52 Å. There are nineteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Er3+ and one Ti4+ atom. In the second O2- site, O2- is bonded to two equivalent Er3+ and two Ti4+ atoms to form distorted OEr2Ti2 tetrahedra that share corners with two OEr3Ti tetrahedra, an edgeedge with one OEr3Ti tetrahedra, and an edgeedge with one OTi4 trigonal pyramid. In the third O2- site, O2- is bonded to three Er3+ and one Ti4+ atom to form OEr3Ti tetrahedra that share corners with three OEr2Ti2 tetrahedra and edges with two OEr3Ti tetrahedra. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Er3+ and two Ti4+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Er3+ and one Ti4+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Er3+ and two equivalent Ti4+ atoms. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Er3+ and one Ti4+ atom. In the eighth O2- site, O2- is bonded to three Er3+ and one Ti4+ atom to form distorted OEr3Ti tetrahedra that share corners with ten OEr4 tetrahedra and edges with two equivalent OEr2Ti2 tetrahedra. In the ninth O2- site, O2- is bonded to three Er3+ and one Ti4+ atom to form distorted OEr3Ti tetrahedra that share corners with five OEr4 tetrahedra and edges with three OEr3Ti tetrahedra. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Er3+ and two Ti4+ atoms. In the eleventh O2- site, O2- is bonded to four Er3+ atoms to form a mixture of edge and corner-sharing OEr4 tetrahedra. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to three Er3+ and one Ti4+ atom. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to three Er3+ and one Ti4+ atom. In the fourteenth O2- site, O2- is bonded to two Er3+ and two equivalent Ti4+ atoms to form distorted OEr2Ti2 tetrahedra that share corners with three OEr4 tetrahedra and an edgeedge with one OTi4 trigonal pyramid. In the fifteenth O2- site, O2- is bonded to two equivalent Er3+ and two Ti4+ atoms to form distorted OEr2Ti2 tetrahedra that share corners with six OEr2Ti2 tetrahedra, a cornercorner with one OTi4 trigonal pyramid, and edges with two equivalent OEr2Ti2 tetrahedra. In the sixteenth O2- site, O2- is bonded to four Ti4+ atoms to form a mixture of distorted edge and corner-sharing OTi4 trigonal pyramids. In the seventeenth O2- site, O2- is bonded to two Er3+ and two Ti4+ atoms to form a mixture of distorted edge and corner-sharing OEr2Ti2 tetrahedra. In the eighteenth O2- site, O2- is bonded to three Er3+ and one Ti4+ atom to form a mixture of edge and corner-sharing OEr3Ti tetrahedra. In the nineteenth O2- site, O2- is bonded to three Er3+ and one Ti4+ atom to form distorted OEr3Ti tetrahedra that share corners with six OEr2Ti2 tetrahedra, a cornercorner with one OTi4 trigonal pyramid, and edges with three OEr3Ti tetrahedra.