DOE OSTI2020
Ca3Fe2(ReO6)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.33–2.72 Å. In the second Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.61 Å. In the third Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.70 Å. There are two inequivalent Re6+ sites. In the first Re6+ site, Re6+ is bonded to six O2- atoms to form ReO6 octahedra that share corners with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 22–31°. There are a spread of Re–O bond distances ranging from 1.85–2.01 Å. In the second Re6+ site, Re6+ is bonded to six O2- atoms to form ReO6 octahedra that share corners with six FeO6 octahedra. The corner-sharing octahedra tilt angles range from 23–32°. There are a spread of Re–O bond distances ranging from 1.87–2.00 Å. There are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six ReO6 octahedra. The corner-sharing octahedra tilt angles range from 22–31°. There are a spread of Fe–O bond distances ranging from 2.01–2.09 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six ReO6 octahedra. The corner-sharing octahedra tilt angles range from 23–32°. There are a spread of Fe–O bond distances ranging from 2.01–2.07 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Re6+, and one Fe3+ atom. In the second O2- site, O2- is bonded in a distorted T-shaped geometry to one Ca2+, one Re6+, and one Fe3+ atom. In the third O2- site, O2- is bonded to two Ca2+, one Re6+, and one Fe3+ atom to form distorted corner-sharing OCa2FeRe tetrahedra. In the fourth O2- site, O2- is bonded to two Ca2+, one Re6+, and one Fe3+ atom to form a mixture of distorted edge and corner-sharing OCa2FeRe tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Re6+, and one Fe3+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Re6+, and one Fe3+ atom. In the seventh O2- site, O2- is bonded to two Ca2+, one Re6+, and one Fe3+ atom to form a mixture of distorted edge and corner-sharing OCa2FeRe trigonal pyramids. In the eighth O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+, one Re6+, and one Fe3+ atom. In the ninth O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+, one Re6+, and one Fe3+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Re6+, and one Fe3+ atom. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Re6+, and one Fe3+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to two Ca2+, one Re6+, and one Fe3+ atom.