Materials Data on SrTa2Bi2O9 by Materials Project

Abstract

SrBi2Ta2O9 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with four equivalent SrO12 cuboctahedra, faces with four equivalent SrO12 cuboctahedra, and faces with eight equivalent TaO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.64–2.96 Å. Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with five equivalent TaO6 octahedra and faces with four equivalent SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 5–18°. There are a spread of Ta–O bond distances ranging from 1.91–2.08 Å. Bi3+ is bonded in a 3-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.11–2.95 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to one Ta5+ and one Bi3+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Bi3+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sr2+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Sr2+ and two equivalent Ta5+ atoms.