Materials Data on Cs3Cr2I9 by Materials Project

Abstract

Cs3Cr2I9 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded to nine equivalent I1- atoms to form distorted CsI9 cuboctahedra that share corners with nine CsI9 cuboctahedra, edges with three equivalent CsI12 cuboctahedra, edges with three equivalent CrI6 octahedra, faces with three equivalent CsI9 cuboctahedra, and a faceface with one CrI6 octahedra. There are three shorter (4.07 Å) and six longer (4.17 Å) Cs–I bond lengths. In the second Cs1+ site, Cs1+ is bonded to twelve I1- atoms to form CsI12 cuboctahedra that share corners with twelve CsI9 cuboctahedra, edges with six equivalent CsI9 cuboctahedra, and faces with six equivalent CrI6 octahedra. There are six shorter (4.14 Å) and six longer (4.15 Å) Cs–I bond lengths. Cr3+ is bonded to six I1- atoms to form CrI6 octahedra that share edges with three equivalent CsI9 cuboctahedra, faces with four CsI9 cuboctahedra, and a faceface with one CrI6 octahedra. There are three shorter (2.71 Å) and three longer (2.82 Å) Cr–I bond lengths. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a distorted single-bond geometry to four Cs1+ and one Cr3+ atom. In the second I1- site, I1- is bonded in a 2-coordinate geometry to two equivalent Cs1+ and two equivalent Cr3+ atoms.