Materials Data on Ca2Ti2O5 by Materials Project

Abstract

Ca2Ti2O5 crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.37–2.86 Å. In the second Ca2+ site, Ca2+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.37–2.87 Å. There are two inequivalent Ti3+ sites. In the first Ti3+ site, Ti3+ is bonded to five O2- atoms to form corner-sharing TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 1.92–2.00 Å. In the second Ti3+ site, Ti3+ is bonded to five O2- atoms to form corner-sharing TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 1.93–2.00 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ca2+ and two Ti3+ atoms to form distorted OCa4Ti2 octahedra that share corners with eight OCa2Ti2 tetrahedra, edges with two equivalent OCa4Ti2 octahedra, and edges with two OCa2Ti2 tetrahedra. In the second O2- site, O2- is bonded to two equivalent Ca2+ and two equivalent Ti3+ atoms to form distorted OCa2Ti2 tetrahedra that share corners with four equivalent OCa4Ti2 octahedra, corners with four equivalent OCa2Ti2 tetrahedra, and an edgeedge with one OCa4Ti2 octahedra. The corner-sharing octahedra tilt angles range from 8–76°. In the third O2- site, O2- is bonded to two equivalent Ca2+ and two equivalent Ti3+ atoms to form distorted OCa2Ti2 tetrahedra that share corners with four equivalent OCa4Ti2 octahedra, corners with four equivalent OCa2Ti2 tetrahedra, and an edgeedge with one OCa4Ti2 octahedra. The corner-sharing octahedra tilt angles range from 8–76°. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to four Ca2+ and two equivalent Ti3+ atoms. In the fifth O2- site, O2- is bonded in a 6-coordinate geometry to four Ca2+ and two equivalent Ti3+ atoms.