DOI: 10.17188/1268422
title: Materials Data on Ti7O8 by Materials Project

description: Ti7O8 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are seven inequivalent Ti+2.29+ sites. In the first Ti+2.29+ site, Ti+2.29+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three TiO6 octahedra, a cornercorner with one TiO5 square pyramid, a cornercorner with one TiO5 trigonal bipyramid, edges with six TiO6 octahedra, and edges with two equivalent TiO5 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 7–13°. There are a spread of Ti–O bond distances ranging from 2.02–2.21 Å. In the second Ti+2.29+ site, Ti+2.29+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three TiO6 octahedra, a cornercorner with one TiO5 trigonal bipyramid, edges with six TiO6 octahedra, and edges with three equivalent TiO5 square pyramids. The corner-sharing octahedra tilt angles range from 1–18°. There are a spread of Ti–O bond distances ranging from 2.02–2.19 Å. In the third Ti+2.29+ site, Ti+2.29+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three TiO6 octahedra, a cornercorner with one TiO5 square pyramid, a cornercorner with one TiO5 trigonal bipyramid, edges with eight TiO6 octahedra, and edges with two equivalent TiO5 square pyramids. The corner-sharing octahedra tilt angles range from 7–17°. There are a spread of Ti–O bond distances ranging from 2.07–2.22 Å. In the fourth Ti+2.29+ site, Ti+2.29+ is bonded in a rectangular see-saw-like geometry to four O2- atoms. There are three shorter (2.01 Å) and one longer (2.11 Å) Ti–O bond lengths. In the fifth Ti+2.29+ site, Ti+2.29+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three TiO6 octahedra, edges with eight TiO6 octahedra, an edgeedge with one TiO5 square pyramid, and an edgeedge with one TiO5 trigonal bipyramid. The corner-sharing octahedra tilt angles range from 1–19°. There are a spread of Ti–O bond distances ranging from 2.04–2.17 Å. In the sixth Ti+2.29+ site, Ti+2.29+ is bonded to five O2- atoms to form TiO5 trigonal bipyramids that share corners with three TiO6 octahedra, a cornercorner with one TiO5 square pyramid, corners with two equivalent TiO5 trigonal bipyramids, and edges with three TiO6 octahedra. The corner-sharing octahedra tilt angles range from 3–17°. There are a spread of Ti–O bond distances ranging from 2.02–2.08 Å. In the seventh Ti+2.29+ site, Ti+2.29+ is bonded to five O2- atoms to form TiO5 square pyramids that share corners with two TiO6 octahedra, corners with two equivalent TiO5 square pyramids, a cornercorner with one TiO5 trigonal bipyramid, and edges with six TiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–15°. There are a spread of Ti–O bond distances ranging from 1.99–2.23 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded to five Ti+2.29+ atoms to form OTi5 square pyramids that share corners with four OTi5 square pyramids, edges with three equivalent OTi6 octahedra, and edges with five OTi5 square pyramids. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ti+2.29+ atoms. In the third O2- site, O2- is bonded to five Ti+2.29+ atoms to form OTi5 square pyramids that share a cornercorner with one OTi6 octahedra, corners with four OTi5 square pyramids, edges with two equivalent OTi6 octahedra, and edges with three OTi5 square pyramids. The corner-sharing octahedral tilt angles are 8°. In the fourth O2- site, O2- is bonded to five Ti+2.29+ atoms to form OTi5 square pyramids that share corners with four OTi5 square pyramids, edges with three equivalent OTi6 octahedra, and edges with five OTi5 square pyramids. In the fifth O2- site, O2- is bonded to five Ti+2.29+ atoms to form OTi5 square pyramids that share a cornercorner with one OTi6 octahedra, corners with four OTi5 square pyramids, edges with two equivalent OTi6 octahedra, and edges with three OTi5 square pyramids. The corner-sharing octahedral tilt angles are 7°. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ti+2.29+ atoms. In the seventh O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ti+2.29+ atoms. In the eighth O2- site, O2- is bonded to six Ti+2.29+ atoms to form OTi6 octahedra that share corners with two equivalent OTi6 octahedra, corners with two OTi5 square pyramids, and edges with ten OTi5 square pyramids. The corner-sharing octahedral tilt angles are 17°.