Bi9I2 crystallizes in the monoclinic P2_1/m space group. There are nine inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 6-coordinate geometry to one Bi(8), two equivalent Bi(2), and three equivalent I(1) atoms. In the second Bi site, Bi(2) is bonded in a 4-coordinate geometry to one Bi(3), one Bi(7), and two equivalent Bi(1) atoms. In the third Bi site, Bi(3) is bonded in a 3-coordinate geometry to one Bi(2) and two equivalent Bi(4) atoms. In the fourth Bi site, Bi(4) is bonded in a distorted rectangular see-saw-like geometry to one Bi(5), one Bi(6), and two equivalent Bi(3) atoms. In the fifth Bi site, Bi(5) is bonded in a 3-coordinate geometry to one Bi(4) and two equivalent Bi(6) atoms. In the sixth Bi site, Bi(6) is bonded in a distorted rectangular see-saw-like geometry to one Bi(4), one Bi(7), and two equivalent Bi(5) atoms. In the seventh Bi site, Bi(7) is bonded in a 4-coordinate geometry to one Bi(2), one Bi(6), and two equivalent Bi(7) atoms. In the eighth Bi site, Bi(8) is bonded in a 3-coordinate geometry to one Bi(1) and two equivalent Bi(9) atoms. In the ninth Bi site, Bi(9) is bonded in a 2-coordinate geometry to two equivalent Bi(8), one I(1), and one I(2) atom. There are two inequivalent I sites. In the first I site, I(1) is bonded in a single-bond geometry to one Bi(9) and three equivalent Bi(1) atoms. In the second I site, I(2) is bonded in a single-bond geometry to one Bi(9) atom.
Bi9I2 crystallizes in the monoclinic P2_1/m space group. There are nine inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 6-coordinate geometry to one Bi(8), two equivalent Bi(2), and three equivalent I(1) atoms. The Bi(1)-Bi(8) bond length is 3.04 Å. Both Bi(1)-Bi(2) bond lengths are 3.06 Å. All Bi(1)-I(1) bond lengths are 3.67 Å. In the second Bi site, Bi(2) is bonded in a 4-coordinate geometry to one Bi(3), one Bi(7), and two equivalent Bi(1) atoms. The Bi(2)-Bi(3) bond length is 3.06 Å. The Bi(2)-Bi(7) bond length is 3.57 Å. In the third Bi site, Bi(3) is bonded in a 3-coordinate geometry to one Bi(2) and two equivalent Bi(4) atoms. Both Bi(3)-Bi(4) bond lengths are 3.06 Å. In the fourth Bi site, Bi(4) is bonded in a distorted rectangular see-saw-like geometry to one Bi(5), one Bi(6), and two equivalent Bi(3) atoms. The Bi(4)-Bi(5) bond length is 3.08 Å. The Bi(4)-Bi(6) bond length is 3.54 Å. In the fifth Bi site, Bi(5) is bonded in a 3-coordinate geometry to one Bi(4) and two equivalent Bi(6) atoms. Both Bi(5)-Bi(6) bond lengths are 3.05 Å. In the sixth Bi site, Bi(6) is bonded in a distorted rectangular see-saw-like geometry to one Bi(4), one Bi(7), and two equivalent Bi(5) atoms. The Bi(6)-Bi(7) bond length is 3.08 Å. In the seventh Bi site, Bi(7) is bonded in a 4-coordinate geometry to one Bi(2), one Bi(6), and two equivalent Bi(7) atoms. Both Bi(7)-Bi(7) bond lengths are 3.05 Å. In the eighth Bi site, Bi(8) is bonded in a 3-coordinate geometry to one Bi(1) and two equivalent Bi(9) atoms. Both Bi(8)-Bi(9) bond lengths are 3.08 Å. In the ninth Bi site, Bi(9) is bonded in a 2-coordinate geometry to two equivalent Bi(8), one I(1), and one I(2) atom. The Bi(9)-I(1) bond length is 3.13 Å. The Bi(9)-I(2) bond length is 3.09 Å. There are two inequivalent I sites. In the first I site, I(1) is bonded in a single-bond geometry to one Bi(9) and three equivalent Bi(1) atoms. In the second I site, I(2) is bonded in a single-bond geometry to one Bi(9) atom.