DOI: 10.17188/1662676
title: Materials Data on Sr3Ta4Ti4O21 by Materials Project

description: Sr3Ti4Ta4O21 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 6-coordinate geometry to twelve O2- atoms. There are a spread of Sr–O bond distances ranging from 2.63–3.20 Å. In the second Sr2+ site, Sr2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sr–O bond distances ranging from 2.72–2.75 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share a cornercorner with one TiO6 octahedra, corners with four TaO6 octahedra, an edgeedge with one TiO6 octahedra, and an edgeedge with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 30–46°. There are a spread of Ti–O bond distances ranging from 1.85–2.16 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with two TiO6 octahedra, corners with three TaO6 octahedra, an edgeedge with one TiO6 octahedra, and an edgeedge with one TaO6 octahedra. The corner-sharing octahedra tilt angles range from 29–46°. There are a spread of Ti–O bond distances ranging from 1.84–2.17 Å. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra and corners with four TiO6 octahedra. The corner-sharing octahedra tilt angles range from 41–44°. There are a spread of Ta–O bond distances ranging from 1.98–2.02 Å. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with two equivalent TaO6 octahedra, corners with three TiO6 octahedra, and edges with two TiO6 octahedra. The corner-sharing octahedra tilt angles range from 30–46°. There are a spread of Ta–O bond distances ranging from 1.91–2.08 Å. There are eleven inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Sr2+, one Ti4+, and one Ta5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Sr2+ and two equivalent Ti4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Sr2+, two Ti4+, and one Ta5+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Sr2+, two Ti4+, and one Ta5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Sr2+, one Ti4+, and one Ta5+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+ and two Ta5+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Sr2+, one Ti4+, and one Ta5+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+, one Ti4+, and one Ta5+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Sr2+ and two Ta5+ atoms. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to two Sr2+, one Ti4+, and one Ta5+ atom. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to one Sr2+, two Ti4+, and one Ta5+ atom.