Materials Data on Ba4SiSb2Se11 by Materials Project
Ba4SiSb2Se11 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine Se2- atoms. There are a spread of Ba–Se bond distances ranging from 3.41–3.74 Å. In the second Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to ten Se2- atoms. There are a spread of Ba–Se bond distances ranging from 3.35–3.91 Å. Si4+ is bonded to four Se2- atoms to form SiSe4 tetrahedra that share an edgeedge with one SbSe5 square pyramid. There are a spread of Si–Se bond distances ranging from 2.28–2.30 Å. There are two inequivalent Sb5+ sites. In the first Sb5+ site, Sb5+ is bonded in a distorted see-saw-like geometry to four Se2- atoms. There are a spread of Sb–Se bond distances ranging from 2.61–3.20 Å. In the second Sb5+ site, Sb5+ is bonded to five Se2- atoms to form distorted SbSe5 square pyramids that share an edgeedge with one SiSe4 tetrahedra. There are a spread of Sb–Se bond distances ranging from 2.58–3.17 Å. There are nine inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to four equivalent Ba2+, one Sb5+, and two equivalent Se2- atoms. There are one shorter (2.44 Å) and one longer (3.39 Å) Se–Se bond lengths. In the second Se2- site, Se2- is bonded to four equivalent Ba2+ and one Sb5+ atom to form a mixture of distorted corner and edge-sharing SeBa4Sb square pyramids. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to three Ba2+ and two Sb5+ atoms. In the fourth Se2- site, Se2- is bonded to four equivalent Ba2+ and one Sb5+ atom to form a mixture of distorted corner and edge-sharing SeBa4Sb square pyramids. In the fifth Se2- site, Se2- is bonded in a 1-coordinate geometry to two Ba2+, one Si4+, one Sb5+, and one Se2- atom. The Se–Se bond length is 3.39 Å. In the sixth Se2- site, Se2- is bonded to four Ba2+ and one Si4+ atom to form distorted SeBa4Si square pyramids that share corners with four SeBa4Sb square pyramids, edges with three SeBa4Sb square pyramids, and a faceface with one SeBa4Si square pyramid. In the seventh Se2- site, Se2- is bonded to four equivalent Ba2+ and one Si4+ atom to form a mixture of distorted edge and face-sharing SeBa4Si square pyramids. In the eighth Se2- site, Se2- is bonded in a 5-coordinate geometry to four Ba2+ and one Se2- atom. The Se–Se bond length is 2.41 Å. In the ninth Se2- site, Se2- is bonded in a 2-coordinate geometry to four equivalent Ba2+ and five Se2- atoms.