Materials Data on Er2TiO5 by Materials Project
Er2TiO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Er3+ sites. In the first Er3+ site, Er3+ is bonded to six O2- atoms to form distorted ErO6 octahedra that share corners with two equivalent ErO6 octahedra, corners with four equivalent TiO6 octahedra, and edges with six ErO6 octahedra. The corner-sharing octahedra tilt angles range from 58–65°. There are a spread of Er–O bond distances ranging from 2.28–2.31 Å. In the second Er3+ site, Er3+ is bonded to six O2- atoms to form ErO6 octahedra that share corners with four ErO6 octahedra, corners with four equivalent TiO6 octahedra, and edges with four ErO6 octahedra. The corner-sharing octahedra tilt angles range from 51–64°. There are a spread of Er–O bond distances ranging from 2.20–2.33 Å. Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with eight ErO6 octahedra, and edges with two equivalent TiO6 octahedra. The corner-sharing octahedra tilt angles range from 34–65°. There are a spread of Ti–O bond distances ranging from 1.85–2.37 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Er3+ atoms to form OEr4 tetrahedra that share corners with ten OEr4 tetrahedra and edges with three OEr3Ti tetrahedra. In the second O2- site, O2- is bonded in a 2-coordinate geometry to three equivalent Ti4+ atoms. In the third O2- site, O2- is bonded to three Er3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing OEr3Ti tetrahedra. In the fourth O2- site, O2- is bonded to three equivalent Er3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing OEr3Ti tetrahedra. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Er3+ and one Ti4+ atom.