Materials Data on BaTi4O9 by Materials Project
BaTi4O9 crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. Ba2+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Ba–O bond distances ranging from 2.86–3.11 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 25–34°. There are a spread of Ti–O bond distances ranging from 1.87–2.14 Å. In the second 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 1.77–2.34 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Ba2+ and two equivalent Ti4+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ba2+ and two Ti4+ atoms. In the third O2- site, O2- is bonded in a distorted water-like geometry to two equivalent Ba2+ and two Ti4+ atoms. In the fourth O2- site, O2- is bonded to four Ti4+ atoms to form a mixture of distorted edge and corner-sharing OTi4 trigonal pyramids. In the fifth O2- site, O2- is bonded in a distorted T-shaped geometry to three Ti4+ atoms.