Materials Data on Ho2TiO5 by Materials Project

Abstract

Ho2TiO5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six O2- atoms to form distorted HoO6 octahedra that share corners with two equivalent HoO6 octahedra, corners with four equivalent TiO6 octahedra, and edges with six HoO6 octahedra. The corner-sharing octahedra tilt angles range from 58–65°. There are a spread of Ho–O bond distances ranging from 2.28–2.32 Å. In the second Ho3+ site, Ho3+ is bonded to six O2- atoms to form HoO6 octahedra that share corners with four HoO6 octahedra, corners with four equivalent TiO6 octahedra, and edges with four HoO6 octahedra. The corner-sharing octahedra tilt angles range from 51–65°. There are a spread of Ho–O bond distances ranging from 2.20–2.34 Å. Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with eight HoO6 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 1.85–2.36 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ho3+ atoms to form OHo4 tetrahedra that share corners with ten OHo4 tetrahedra and edges with three OHo3Ti 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 Ho3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing OHo3Ti tetrahedra. In the fourth O2- site, O2- is bonded to three equivalent Ho3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing OHo3Ti tetrahedra. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ho3+ and one Ti4+ atom.