DOE OSTI2020
Sr4La(CoO3)5 is (Cubic) Perovskite-derived structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with two equivalent LaO12 cuboctahedra, corners with ten SrO12 cuboctahedra, faces with two equivalent LaO12 cuboctahedra, faces with four SrO12 cuboctahedra, and faces with eight CoO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.71–2.81 Å. In the second Sr2+ site, Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with three equivalent LaO12 cuboctahedra, corners with nine SrO12 cuboctahedra, a faceface with one LaO12 cuboctahedra, faces with five SrO12 cuboctahedra, and faces with eight CoO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.69–2.82 Å. La3+ is bonded to twelve O2- atoms to form LaO12 cuboctahedra that share corners with two equivalent LaO12 cuboctahedra, corners with ten SrO12 cuboctahedra, faces with six SrO12 cuboctahedra, and faces with eight CoO6 octahedra. There are a spread of La–O bond distances ranging from 2.67–2.73 Å. There are three inequivalent Co+3.80+ sites. In the first Co+3.80+ site, Co+3.80+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six CoO6 octahedra, faces with two equivalent LaO12 cuboctahedra, and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of Co–O bond distances ranging from 1.89–1.96 Å. In the second Co+3.80+ site, Co+3.80+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six CoO6 octahedra, faces with two equivalent LaO12 cuboctahedra, and faces with six SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 2–4°. There is two shorter (1.85 Å) and four longer (1.98 Å) Co–O bond length. In the third Co+3.80+ site, Co+3.80+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six CoO6 octahedra, a faceface with one LaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of Co–O bond distances ranging from 1.92–2.07 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to three Sr2+, one La3+, and two Co+3.80+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to three Sr2+, one La3+, and two Co+3.80+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to four Sr2+ and two equivalent Co+3.80+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four Sr2+ and two Co+3.80+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to three Sr2+, one La3+, and two Co+3.80+ atoms. In the sixth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+, two equivalent La3+, and two equivalent Co+3.80+ atoms.