Materials Data on Sm2Ti2O5 by Materials Project

Abstract

Sm2Ti2O5 crystallizes in the orthorhombic Ima2 space group. The structure is three-dimensional. Sm3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Sm–O bond distances ranging from 2.36–2.80 Å. There are two inequivalent Ti2+ sites. In the first Ti2+ site, Ti2+ is bonded to six O2- atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 30°. There are four shorter (2.01 Å) and two longer (2.02 Å) Ti–O bond lengths. In the second Ti2+ site, Ti2+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Ti–O bond distances ranging from 1.95–2.15 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Sm3+ and two equivalent Ti2+ atoms to form distorted OSm2Ti2 trigonal pyramids that share corners with two equivalent OSm4Ti2 octahedra, corners with four equivalent OSm2Ti2 trigonal pyramids, an edgeedge with one OSm4Ti2 octahedra, and edges with two equivalent OSm2Ti2 trigonal pyramids. The corner-sharing octahedral tilt angles are 62°. In the second O2- site, O2- is bonded in a 5-coordinate geometry to three equivalent Sm3+ and two Ti2+ atoms. In the third O2- site, O2- is bonded to four equivalent Sm3+ and two equivalent Ti2+ atoms to form distorted OSm4Ti2 octahedra that share corners with four equivalent OSm2Ti2 trigonal pyramids, edges with two equivalent OSm2Ti2 trigonal pyramids, and faces with two equivalent OSm4Ti2 octahedra.