Materials Data on Ba3Ta4NbO15 by Materials Project

Abstract

Ba3Ta4NbO15 crystallizes in the tetragonal P4/mbm 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 faces with two equivalent BaO12 cuboctahedra and faces with eight equivalent TaO6 octahedra. There are eight shorter (2.83 Å) and four longer (2.85 Å) Ba–O bond lengths. In the second Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are two shorter (2.86 Å) and four longer (2.89 Å) Ba–O bond lengths. Ta+4.75+ is bonded to six O2- atoms to form TaO6 octahedra that share a cornercorner with one NbO6 octahedra, corners with five equivalent TaO6 octahedra, and faces with two equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–39°. There are a spread of Ta–O bond distances ranging from 1.95–2.06 Å. Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with two equivalent NbO6 octahedra and corners with four equivalent TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–36°. There are two shorter (2.01 Å) and four longer (2.03 Å) Nb–O bond lengths. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ba2+ and two equivalent Ta+4.75+ atoms. In the second O2- site, O2- is bonded in a linear geometry to two equivalent Nb5+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ba2+ and two equivalent Ta+4.75+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to one Ba2+ and two equivalent Ta+4.75+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+, one Ta+4.75+, and one Nb5+ atom.