DOE OSTI2020
Ba2Sr(IrO3)3 is (Cubic) Perovskite-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are four 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 BaO12 cuboctahedra, corners with six SrO12 cuboctahedra, faces with six BaO12 cuboctahedra, and faces with eight IrO6 octahedra. There are six shorter (2.89 Å) and six longer (3.05 Å) Ba–O bond lengths. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, corners with six IrO6 octahedra, faces with two BaO12 cuboctahedra, faces with six SrO12 cuboctahedra, and faces with six IrO6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of Ba–O bond distances ranging from 2.89–3.06 Å. In the third Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, corners with six IrO6 octahedra, faces with three equivalent SrO12 cuboctahedra, faces with five BaO12 cuboctahedra, and faces with six IrO6 octahedra. The corner-sharing octahedra tilt angles range from 12–13°. There are a spread of Ba–O bond distances ranging from 2.89–3.10 Å. In the fourth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, corners with six IrO6 octahedra, faces with three equivalent SrO12 cuboctahedra, faces with five BaO12 cuboctahedra, and faces with six IrO6 octahedra. The corner-sharing octahedral tilt angles are 13°. There are a spread of Ba–O bond distances ranging from 2.89–3.10 Å. There are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with three equivalent BaO12 cuboctahedra, corners with nine SrO12 cuboctahedra, faces with six BaO12 cuboctahedra, and faces with eight IrO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.89–3.01 Å. In the second Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, corners with six equivalent SrO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with eight IrO6 octahedra. There are six shorter (2.89 Å) and six longer (2.92 Å) Sr–O bond lengths. In the third Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with twelve SrO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with eight IrO6 octahedra. There are six shorter (2.89 Å) and six longer (2.98 Å) Sr–O bond lengths. There are six inequivalent Ir4+ sites. In the first Ir4+ site, Ir4+ is bonded to six O2- atoms to form IrO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent IrO6 octahedra, faces with three equivalent BaO12 cuboctahedra, faces with four SrO12 cuboctahedra, and a faceface with one IrO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.01 Å) and three longer (2.04 Å) Ir–O bond lengths. In the second Ir4+ site, Ir4+ is bonded to six O2- atoms to form IrO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent IrO6 octahedra, a faceface with one SrO12 cuboctahedra, faces with six BaO12 cuboctahedra, and a faceface with one IrO6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are three shorter (2.02 Å) and three longer (2.03 Å) Ir–O bond lengths. In the third Ir4+ site, Ir4+ is bonded to six O2- atoms to form IrO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent IrO6 octahedra, a faceface with one SrO12 cuboctahedra, faces with six BaO12 cuboctahedra, and a faceface with one IrO6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are three shorter (2.02 Å) and three longer (2.04 Å) Ir–O bond lengths. In the fourth Ir4+ site, Ir4+ is bonded to six O2- atoms to form IrO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent IrO6 octahedra, faces with three equivalent BaO12 cuboctahedra, faces with four SrO12 cuboctahedra, and a faceface with one IrO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.01 Å) and three longer (2.04 Å) Ir–O bond lengths. In the fifth Ir4+ site, Ir4+ is bonded to six O2- atoms to form IrO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent IrO6 octahedra, faces with three equivalent SrO12 cuboctahedra, faces with four BaO12 cuboctahedra, and a faceface with one IrO6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are three shorter (2.01 Å) and three longer (2.04 Å) Ir–O bond lengths. In the sixth Ir4+ site, Ir4+ is bonded to six O2- atoms to form IrO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent IrO6 octahedra, faces with three equivalent SrO12 cuboctahedra, faces with four BaO12 cuboctahedra, and a faceface with one IrO6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are three shorter (2.02 Å) and three longer (2.04 Å) Ir–O bond lengths. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, two equivalent Sr2+, and two equivalent Ir4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ir4+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ba2+, two Sr2+, and two Ir4+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to three Ba2+, one Sr2+, and two Ir4+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to three Ba2+, one Sr2+, and two Ir4+ atoms. In the sixth O2- site, O2- is bonded in a 6-coordinate geometry to two Ba2+, two equivalent Sr2+, and two Ir4+ atoms. In the seventh O2- site, O2- is bonded in a 6-coordinate geometry to two equivalent Ba2+, two equivalent Sr2+, and two equivalent Ir4+ atoms.