DOE OSTI2020
SrLaTaCoO6 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are six inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form distorted SrO12 cuboctahedra that share corners with nine SrO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with three equivalent LaO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.69–3.12 Å. In the second Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with twelve SrO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with three equivalent LaO12 cuboctahedra, faces with three equivalent CoO6 octahedra, and faces with five TaO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.76–2.90 Å. 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 LaO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are nine shorter (2.84 Å) and three longer (2.86 Å) Sr–O bond lengths. In the fourth Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with six equivalent SrO12 cuboctahedra, corners with six LaO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with two CoO6 octahedra, and faces with six TaO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.84–2.91 Å. In the fifth Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with twelve SrO12 cuboctahedra, faces with six LaO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.83–2.86 Å. In the sixth Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with nine SrO12 cuboctahedra, faces with six LaO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.83–2.87 Å. There are six inequivalent La3+ sites. In the first La3+ site, La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with three equivalent SrO12 cuboctahedra, corners with nine LaO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of La–O bond distances ranging from 2.82–2.84 Å. In the second La3+ site, La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with twelve LaO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are six shorter (2.84 Å) and six longer (2.85 Å) La–O bond lengths. In the third La3+ site, La3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are three shorter (2.45 Å) and six longer (2.87 Å) La–O bond lengths. In the fourth La3+ site, La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with twelve LaO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of La–O bond distances ranging from 2.83–2.86 Å. In the fifth La3+ site, La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with twelve LaO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with four TaO6 octahedra, and faces with four CoO6 octahedra. There are a spread of La–O bond distances ranging from 2.83–2.85 Å. In the sixth La3+ site, La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with three equivalent SrO12 cuboctahedra, corners with nine LaO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with two TaO6 octahedra, and faces with six CoO6 octahedra. There are nine shorter (2.84 Å) and three longer (2.85 Å) La–O bond lengths. There are six inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent CoO6 octahedra, a faceface with one LaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. There is three shorter (1.93 Å) and three longer (2.05 Å) Ta–O bond length. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent CoO6 octahedra, a faceface with one LaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. There is three shorter (1.94 Å) and three longer (2.05 Å) Ta–O bond length. In the third Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six CoO6 octahedra, faces with four SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Ta–O bond lengths are 1.98 Å. In the fourth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six CoO6 octahedra, faces with four SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There is three shorter (1.98 Å) and three longer (1.99 Å) Ta–O bond length. In the fifth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six CoO6 octahedra, faces with four SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Ta–O bond lengths are 1.98 Å. In the sixth Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six CoO6 octahedra, a faceface with one SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There is three shorter (1.96 Å) and three longer (2.00 Å) Ta–O bond length. There are six inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent CoO6 octahedra, faces with three equivalent LaO12 cuboctahedra, and faces with four SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–5°. There are three shorter (2.02 Å) and three longer (2.06 Å) Co–O bond lengths. In the second Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six TaO6 octahedra, faces with three equivalent LaO12 cuboctahedra, and faces with five SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 1°. All Co–O bond lengths are 2.04 Å. In the third Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six TaO6 octahedra, faces with four SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are three shorter (2.04 Å) and three longer (2.05 Å) Co–O bond lengths. In the fourth Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six TaO6 octahedra, faces with four SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Co–O bond lengths are 2.04 Å. In the fifth Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six TaO6 octahedra, faces with three equivalent SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are three shorter (2.04 Å) and three longer (2.05 Å) Co–O bond lengths. In the sixth Co2+ site, Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three equivalent TaO6 octahedra, corners with three equivalent CoO6 octahedra, a faceface with one SrO12 cuboctahedra, and faces with four LaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–5°. There are three shorter (1.98 Å) and three longer (2.06 Å) Co–O bond lengths. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to three Sr2+, one La3+, one Ta5+, and one Co2+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four Sr2+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to three Sr2+, one La3+, one Ta5+, and one Co2+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to two Sr2+, two equivalent La3+, one Ta5+, and one Co2+ atom. In the fifth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+, two La3+, one Ta5+, and one Co2+ atom. In the sixth O2- site, O2- is bonded in a distorted linear geometry to two Sr2+, two equivalent La3+, one Ta5+, and one Co2+ atom. In the seventh O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+, two La3+, one Ta5+, and one Co2+ atom. In the eighth O2- site, O2- is bonded in a distorted linear geometry to two Sr2+, two equivalent La3+, one Ta5+, and one Co2+ atom. In the ninth O2- site, O2- is bonded in a distorted linear geometry to one Sr2+, two equivalent La3+, one Ta5+, and one Co2+ atom. In the tenth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+, two La3+, one Ta5+, and one Co2+ atom. In the eleventh O2- site, O2- is bonded in a distorted linear geometry to four La3+, one Ta5+, and one Co2+ atom. In the twelfth O2- site, O2- is bonded to one Sr2+, three La3+, and two Co2+ atoms to form a mixture of distorted corner and face-sharing OSrLa3Co2 octahedra. The corner-sharing octahedra tilt angles range from 3–60°.