Materials Data on Sr2Ti2O5 by Materials Project

Abstract

Sr2Ti2O5 crystallizes in the orthorhombic Ima2 space group. The structure is three-dimensional. Sr2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Sr–O bond distances ranging from 2.59–3.08 Å. There are two inequivalent Ti3+ sites. In the first Ti3+ site, Ti3+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with four equivalent TiO6 octahedra and corners with two equivalent TiO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 5°. There are a spread of Ti–O bond distances ranging from 2.00–2.08 Å. In the second Ti3+ site, Ti3+ is bonded to four O2- atoms to form TiO4 trigonal pyramids that share corners with two equivalent TiO6 octahedra and corners with two equivalent TiO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 17°. There is one shorter (1.92 Å) and three longer (1.93 Å) Ti–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Sr2+ and two equivalent Ti3+ atoms to form a mixture of distorted face, edge, and corner-sharing OSr4Ti2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Sr2+ and two Ti3+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sr2+ and two equivalent Ti3+ atoms.