Materials Data on Ba2Ti2O5 by Materials Project
Ba2Ti2O5 crystallizes in the orthorhombic Ima2 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 2.78–3.05 Å. There are two inequivalent Ti3+ sites. In the first Ti3+ site, Ti3+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with four equivalent TiO6 octahedra and corners with two equivalent TiO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 3°. There are four shorter (2.06 Å) and two longer (2.10 Å) Ti–O bond lengths. In the second Ti3+ site, Ti3+ is bonded to four O2- atoms to form TiO4 trigonal pyramids that share corners with two equivalent TiO6 octahedra and corners with two equivalent TiO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 13°. There is two shorter (1.91 Å) and two longer (1.95 Å) Ti–O bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Ba2+ and two equivalent Ti3+ atoms to form a mixture of distorted face, edge, and corner-sharing OBa4Ti2 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Ba2+ and two Ti3+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ba2+ and two equivalent Ti3+ atoms.