Materials Data on Ba3CoIr2O9 by Materials Project

Abstract

Ba3CoIr2O9 is (Cubic) Perovskite-derived structured and crystallizes in the hexagonal P6_3/mmc 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 nine BaO12 cuboctahedra, corners with three equivalent IrO6 octahedra, faces with seven BaO12 cuboctahedra, faces with three equivalent CoO6 octahedra, and faces with four equivalent IrO6 octahedra. The corner-sharing octahedral tilt angles are 10°. There are a spread of Ba–O bond distances ranging from 2.93–2.98 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, faces with two equivalent CoO6 octahedra, and faces with six equivalent IrO6 octahedra. There are six shorter (2.93 Å) and six longer (2.98 Å) Ba–O bond lengths. Ir5+ is bonded to six O2- atoms to form IrO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent CoO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one IrO6 octahedra. The corner-sharing octahedral tilt angles are 2°. There are three shorter (1.97 Å) and three longer (2.07 Å) Ir–O bond lengths. Co2+ is bonded to six equivalent O2- atoms to form CoO6 octahedra that share corners with six equivalent IrO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 2°. All Co–O bond lengths are 2.09 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four Ba2+ and two equivalent Ir5+ atoms to form a mixture of distorted face and corner-sharing OBa4Ir2 octahedra. The corner-sharing octahedra tilt angles range from 6–60°. In the second O2- site, O2- is bonded in a distorted linear geometry to four Ba2+, one Ir5+, and one Co2+ atom.