Materials Data on Ca2Ti5(Bi2O9)2 by Materials Project

Abstract

Ca2Bi4Ti5O18 is Pb (Zr_0.50 Ti_0.48) O_3-derived structured and crystallizes in the orthorhombic Aea2 space group. The structure is three-dimensional. Ca2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.59 Å. There are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ti–O bond distances ranging from 1.78–2.47 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 20–30°. There are a spread of Ti–O bond distances ranging from 1.86–2.08 Å. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 21–36°. There are a spread of Ti–O bond distances ranging from 1.84–2.16 Å. There are two inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Bi–O bond distances ranging from 2.28–2.91 Å. In the second Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to seven O2- atoms. There are a spread of Bi–O bond distances ranging from 2.24–3.06 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ti4+ and two equivalent Bi3+ atoms. In the second O2- site, O2- is bonded to four equivalent Bi3+ atoms to form a mixture of edge and corner-sharing OBi4 tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Ti4+ and two equivalent Bi3+ atoms. In the fourth O2- site, O2- is bonded to two equivalent Ca2+ and two Ti4+ atoms to form distorted corner-sharing OCa2Ti2 tetrahedra. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one Ti4+ and three equivalent Bi3+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent Ti4+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ti4+ and two equivalent Bi3+ atoms. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+ and two equivalent Ti4+ atoms. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two equivalent Ti4+, and one Bi3+ atom.