Materials Data on Cs3Bi2I9 by Materials Project
Cs3Bi2I9 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 twelve I1- atoms to form CsI12 cuboctahedra that share corners with nine CsI12 cuboctahedra, corners with three equivalent BiI6 octahedra, faces with seven CsI12 cuboctahedra, and faces with four equivalent BiI6 octahedra. The corner-sharing octahedral tilt angles are 17°. There are a spread of Cs–I bond distances ranging from 4.32–4.49 Å. In the second Cs1+ site, Cs1+ is bonded to twelve I1- atoms to form CsI12 cuboctahedra that share corners with twelve CsI12 cuboctahedra, faces with six equivalent CsI12 cuboctahedra, and faces with six equivalent BiI6 octahedra. There are six shorter (4.32 Å) and six longer (4.44 Å) Cs–I bond lengths. Bi3+ is bonded to six I1- atoms to form BiI6 octahedra that share corners with three equivalent CsI12 cuboctahedra, faces with seven CsI12 cuboctahedra, and a faceface with one BiI6 octahedra. There are three shorter (2.98 Å) and three longer (3.25 Å) Bi–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 Bi3+ atom. In the second I1- site, I1- is bonded in a 6-coordinate geometry to four Cs1+ and two equivalent Bi3+ atoms.