Materials Data on Sr4Ti3Nb2O15 by Materials Project

Abstract

Sr4Ti3Nb2O15 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with twelve SrO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with four TiO6 octahedra, and faces with four equivalent NbO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.79–2.84 Å. In the second Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with nine SrO12 cuboctahedra, faces with six SrO12 cuboctahedra, a faceface with one NbO6 octahedra, and faces with seven TiO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.76–2.81 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three equivalent TiO6 octahedra, corners with three equivalent NbO6 octahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–5°. There is three shorter (1.97 Å) and three longer (1.99 Å) Ti–O bond length. In the second Ti4+ site, Ti4+ is bonded to six equivalent O2- atoms to form TiO6 octahedra that share corners with six equivalent TiO6 octahedra and faces with eight SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ti–O bond lengths are 1.98 Å. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with three equivalent TiO6 octahedra, corners with three equivalent NbO6 octahedra, and faces with five SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are three shorter (2.00 Å) and three longer (2.01 Å) Nb–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to three Sr2+, one Ti4+, and one Nb5+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+ and two equivalent Nb5+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to four Sr2+ and two Ti4+ atoms.