Materials Data on CaTi5O7 by Materials Project
CaTi5O7 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.67 Å. There are three inequivalent Ti+2.40+ sites. In the first Ti+2.40+ site, Ti+2.40+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 7–9°. There are a spread of Ti–O bond distances ranging from 2.08–2.16 Å. In the second Ti+2.40+ site, Ti+2.40+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 7–38°. There are a spread of Ti–O bond distances ranging from 1.97–2.10 Å. In the third Ti+2.40+ site, Ti+2.40+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 9°. There are four shorter (2.18 Å) and two longer (2.25 Å) Ti–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and five Ti+2.40+ atoms to form distorted OCaTi5 octahedra that share corners with four OTi6 octahedra, corners with four equivalent OCa2Ti3 trigonal bipyramids, edges with seven OCaTi5 octahedra, and edges with three equivalent OCa2Ti3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 0–49°. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent Ti+2.40+ atoms. In the third O2- site, O2- is bonded to six Ti+2.40+ atoms to form OTi6 octahedra that share corners with four OCaTi5 octahedra, a cornercorner with one OCa2Ti3 trigonal bipyramid, edges with ten OCaTi5 octahedra, and edges with two equivalent OCa2Ti3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 0–12°. In the fourth O2- site, O2- is bonded to two equivalent Ca2+ and three Ti+2.40+ atoms to form distorted OCa2Ti3 trigonal bipyramids that share corners with five OTi6 octahedra, corners with two equivalent OCa2Ti3 trigonal bipyramids, edges with five OCaTi5 octahedra, and edges with three equivalent OCa2Ti3 trigonal bipyramids. The corner-sharing octahedra tilt angles range from 5–41°.