Materials Data on Bi9I2 by Materials Project
Bi9I2 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are nine inequivalent Bi sites. In the first Bi site, Bi is bonded in a 6-coordinate geometry to three Bi and three equivalent I atoms. There are one shorter (3.07 Å) and two longer (3.08 Å) Bi–Bi bond lengths. There are one shorter (3.64 Å) and two longer (3.69 Å) Bi–I bond lengths. In the second Bi site, Bi is bonded in a 4-coordinate geometry to four Bi atoms. There are one shorter (3.09 Å) and one longer (3.56 Å) Bi–Bi bond lengths. In the third Bi site, Bi is bonded in a 4-coordinate geometry to three Bi atoms. Both Bi–Bi bond lengths are 3.08 Å. In the fourth Bi site, Bi is bonded in a distorted rectangular see-saw-like geometry to four Bi atoms. There are one shorter (3.11 Å) and one longer (3.54 Å) Bi–Bi bond lengths. In the fifth Bi site, Bi is bonded in a 4-coordinate geometry to four Bi atoms. There are two shorter (3.08 Å) and one longer (3.60 Å) Bi–Bi bond lengths. In the sixth Bi site, Bi is bonded in a 4-coordinate geometry to four Bi atoms. The Bi–Bi bond length is 3.11 Å. In the seventh Bi site, Bi is bonded in a 4-coordinate geometry to four Bi atoms. Both Bi–Bi bond lengths are 3.08 Å. In the eighth Bi site, Bi is bonded in a 4-coordinate geometry to four Bi atoms. Both Bi–Bi bond lengths are 3.11 Å. In the ninth Bi site, Bi is bonded in a 2-coordinate geometry to two equivalent Bi and two I atoms. There are one shorter (3.11 Å) and one longer (3.15 Å) Bi–I bond lengths. There are two inequivalent I sites. In the first I site, I is bonded in a single-bond geometry to four Bi atoms. In the second I site, I is bonded in a single-bond geometry to one Bi atom.