DOE OSTI2020
BaSr3Ca2(MoO6)2 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, corners with six equivalent SrO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with four CaO6 octahedra, and faces with four MoO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.97–2.99 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 six equivalent BaO12 cuboctahedra, corners with six equivalent SrO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with four CaO6 octahedra, and faces with four MoO6 octahedra. There are six shorter (2.95 Å) and six longer (2.97 Å) Sr–O bond lengths. 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 BaO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with four CaO6 octahedra, and faces with four MoO6 octahedra. There are nine shorter (2.97 Å) and three longer (2.98 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 three equivalent BaO12 cuboctahedra, faces with three equivalent SrO12 cuboctahedra, faces with four CaO6 octahedra, and faces with four MoO6 octahedra. There are three shorter (2.96 Å) and nine longer (2.97 Å) Sr–O bond lengths. There are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MoO6 octahedra, faces with three equivalent BaO12 cuboctahedra, and faces with five SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are three shorter (2.25 Å) and three longer (2.26 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six MoO6 octahedra, a faceface with one BaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Ca–O bond lengths are 2.25 Å. There are two inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with six CaO6 octahedra, faces with three equivalent BaO12 cuboctahedra, and faces with five SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Mo–O bond lengths are 1.94 Å. In the second Mo6+ site, Mo6+ is bonded to six O2- atoms to form MoO6 octahedra that share corners with six CaO6 octahedra, a faceface with one BaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Mo–O bond lengths are 1.94 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ba2+, two Sr2+, one Ca2+, and one Mo6+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four Sr2+, one Ca2+, and one Mo6+ atom. In the third O2- site, O2- is bonded in a distorted linear geometry to one Ba2+, three Sr2+, one Ca2+, and one Mo6+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to one Ba2+, three Sr2+, one Ca2+, and one Mo6+ atom.