DOE OSTI2020
Ba11(CdSb2)6 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are six inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to six Sb+2.83- atoms to form BaSb6 octahedra that share corners with seven BaSb6 octahedra, corners with two equivalent CdSb4 trigonal pyramids, edges with two equivalent BaSb6 octahedra, edges with two equivalent CdSb4 tetrahedra, a faceface with one BaSb6 octahedra, and a faceface with one CdSb4 trigonal pyramid. The corner-sharing octahedra tilt angles range from 30–53°. There are a spread of Ba–Sb bond distances ranging from 3.45–3.62 Å. In the second Ba2+ site, Ba2+ is bonded to six Sb+2.83- atoms to form BaSb6 octahedra that share corners with six BaSb6 octahedra, corners with three equivalent CdSb4 trigonal pyramids, edges with two equivalent BaSb6 octahedra, edges with two equivalent CdSb4 tetrahedra, and faces with two BaSb6 octahedra. The corner-sharing octahedra tilt angles range from 30–57°. There are a spread of Ba–Sb bond distances ranging from 3.49–3.72 Å. In the third Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six Sb+2.83- atoms. There are a spread of Ba–Sb bond distances ranging from 3.55–3.68 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 5-coordinate geometry to five Sb+2.83- atoms. There are a spread of Ba–Sb bond distances ranging from 3.44–3.90 Å. In the fifth Ba2+ site, Ba2+ is bonded to six Sb+2.83- atoms to form BaSb6 octahedra that share corners with seven BaSb6 octahedra, corners with two equivalent CdSb4 trigonal pyramids, edges with four equivalent BaSb6 octahedra, edges with three equivalent CdSb4 trigonal pyramids, and faces with two BaSb6 octahedra. The corner-sharing octahedra tilt angles range from 35–57°. There are a spread of Ba–Sb bond distances ranging from 3.53–3.76 Å. In the sixth Ba2+ site, Ba2+ is bonded to six Sb+2.83- atoms to form BaSb6 octahedra that share corners with eight BaSb6 octahedra, corners with four equivalent CdSb4 tetrahedra, edges with two equivalent BaSb6 octahedra, and faces with two equivalent BaSb6 octahedra. The corner-sharing octahedra tilt angles range from 35–53°. There are two shorter (3.55 Å) and four longer (3.63 Å) Ba–Sb bond lengths. There are three inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to four Sb+2.83- atoms to form CdSb4 tetrahedra that share corners with two equivalent BaSb6 octahedra, corners with two equivalent CdSb4 tetrahedra, corners with two equivalent CdSb4 trigonal pyramids, and edges with four BaSb6 octahedra. The corner-sharing octahedral tilt angles are 43°. There are a spread of Cd–Sb bond distances ranging from 2.93–3.16 Å. In the second Cd2+ site, Cd2+ is bonded to four Sb+2.83- atoms to form distorted CdSb4 trigonal pyramids that share corners with seven BaSb6 octahedra, corners with two equivalent CdSb4 tetrahedra, corners with two equivalent CdSb4 trigonal pyramids, edges with three equivalent BaSb6 octahedra, and a faceface with one BaSb6 octahedra. The corner-sharing octahedra tilt angles range from 27–45°. There are a spread of Cd–Sb bond distances ranging from 2.93–3.30 Å. In the third Cd2+ site, Cd2+ is bonded in a distorted trigonal planar geometry to three Sb+2.83- atoms. There are two shorter (2.87 Å) and one longer (3.07 Å) Cd–Sb bond lengths. There are six inequivalent Sb+2.83- sites. In the first Sb+2.83- site, Sb+2.83- is bonded in a 8-coordinate geometry to six Ba2+ and two Cd2+ atoms. In the second Sb+2.83- site, Sb+2.83- is bonded in a 7-coordinate geometry to five Ba2+ and two equivalent Cd2+ atoms. In the third Sb+2.83- site, Sb+2.83- is bonded in a 6-coordinate geometry to four Ba2+ and two equivalent Cd2+ atoms. In the fourth Sb+2.83- site, Sb+2.83- is bonded in a 7-coordinate geometry to four Ba2+ and three Cd2+ atoms. In the fifth Sb+2.83- site, Sb+2.83- is bonded in a 8-coordinate geometry to seven Ba2+ and one Cd2+ atom. In the sixth Sb+2.83- site, Sb+2.83- is bonded in a 8-coordinate geometry to six Ba2+, one Cd2+, and one Sb+2.83- atom. The Sb–Sb bond length is 2.86 Å.