Materials Data on BaTi2O5 by Materials Project
BaTi2O5 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent TiO6 octahedra, faces with two equivalent BaO12 cuboctahedra, and faces with four equivalent TiO6 octahedra. The corner-sharing octahedra tilt angles range from 39–43°. There are a spread of Ba–O bond distances ranging from 2.84–3.06 Å. In the second Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to nine O2- atoms. There are a spread of Ba–O bond distances ranging from 2.72–3.01 Å. There are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ti–O bond distances ranging from 1.74–2.09 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with two equivalent TiO6 octahedra, and edges with three TiO6 octahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Ti–O bond distances ranging from 1.83–2.20 Å. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three equivalent TiO6 octahedra, an edgeedge with one TiO6 octahedra, and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Ti–O bond distances ranging from 1.96–2.14 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ba2+ and two equivalent Ti4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two Ti4+ atoms. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ba2+ and one Ti4+ atom. In the fourth O2- site, O2- is bonded to four Ti4+ atoms to form a mixture of distorted edge and corner-sharing OTi4 tetrahedra. In the fifth O2- site, O2- is bonded in a distorted T-shaped geometry to one Ba2+ and three Ti4+ atoms. In the sixth O2- site, O2- is bonded in a distorted linear geometry to three Ba2+ and two equivalent Ti4+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two Ti4+ atoms. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ba2+ and two Ti4+ atoms.