Materials Data on Cr5(Bi3Se8)2 by Materials Project

Abstract

Cr5(Bi3Se8)2 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are three inequivalent Cr+2.80+ sites. In the first Cr+2.80+ site, Cr+2.80+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with two equivalent BiSe7 pentagonal bipyramids and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.51–2.54 Å. In the second Cr+2.80+ site, Cr+2.80+ is bonded to six Se2- atoms to form CrSe6 octahedra that share a cornercorner with one BiSe7 pentagonal bipyramid, edges with six CrSe6 octahedra, and an edgeedge with one BiSe7 pentagonal bipyramid. There are a spread of Cr–Se bond distances ranging from 2.50–2.55 Å. In the third Cr+2.80+ site, Cr+2.80+ is bonded to six Se2- atoms to form CrSe6 octahedra that share corners with two equivalent BiSe7 pentagonal bipyramids and edges with six CrSe6 octahedra. There are a spread of Cr–Se bond distances ranging from 2.50–2.56 Å. There are four inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to seven Se2- atoms to form distorted BiSe7 pentagonal bipyramids that share corners with four CrSe6 octahedra, corners with three equivalent BiSe7 pentagonal bipyramids, an edgeedge with one CrSe6 octahedra, and edges with two equivalent BiSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 30–62°. There are a spread of Bi–Se bond distances ranging from 2.91–3.41 Å. In the second Bi3+ site, Bi3+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Bi–Se bond distances ranging from 2.84–3.52 Å. In the third Bi3+ site, Bi3+ is bonded in a 7-coordinate geometry to seven Se2- atoms. There are a spread of Bi–Se bond distances ranging from 2.88–3.44 Å. In the fourth Bi3+ site, Bi3+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Bi–Se bond distances ranging from 2.91–3.48 Å. There are ten inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Cr+2.80+ and one Bi3+ atom. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three Cr+2.80+ and two Bi3+ atoms. In the third Se2- site, Se2- is bonded in a 5-coordinate geometry to five Bi3+ atoms. In the fourth Se2- site, Se2- is bonded to five Bi3+ atoms to form distorted corner-sharing SeBi5 trigonal bipyramids. In the fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to three Cr+2.80+ and two Bi3+ atoms. In the sixth Se2- site, Se2- is bonded in a 4-coordinate geometry to three Cr+2.80+ and one Bi3+ atom. In the seventh Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to three Cr+2.80+ and one Bi3+ atom. In the eighth Se2- site, Se2- is bonded in a 5-coordinate geometry to five Bi3+ atoms. In the ninth Se2- site, Se2- is bonded in a 5-coordinate geometry to five Bi3+ atoms. In the tenth Se2- site, Se2- is bonded in a 4-coordinate geometry to three Cr+2.80+ and one Bi3+ atom.