B5I crystallizes in the monoclinic C2/c space group. There are five inequivalent B sites. In the first B site, B(1) is bonded in a distorted tetrahedral geometry to one B(1), one B(4), one B(5), and one I(1) atom. In the second B site, B(2) is bonded in a 4-coordinate geometry to one B(3), one B(4), one B(5), and one I(1) atom. In the third B site, B(3) is bonded in a 4-coordinate geometry to one B(2), one B(3), and two equivalent B(4) atoms. In the fourth B site, B(4) is bonded in a 5-coordinate geometry to one B(1), one B(2), one B(5), and two equivalent B(3) atoms. In the fifth B site, B(5) is bonded in a 4-coordinate geometry to one B(1), one B(2), one B(4), and one B(5) atom. I(1) is bonded in a water-like geometry to one B(1) and one B(2) atom.
B5I crystallizes in the monoclinic C2/c space group. There are five inequivalent B sites. In the first B site, B(1) is bonded in a distorted tetrahedral geometry to one B(1), one B(4), one B(5), and one I(1) atom. The B(1)-B(1) bond length is 1.70 Å. The B(1)-B(4) bond length is 1.73 Å. The B(1)-B(5) bond length is 1.70 Å. The B(1)-I(1) bond length is 2.39 Å. In the second B site, B(2) is bonded in a 4-coordinate geometry to one B(3), one B(4), one B(5), and one I(1) atom. The B(2)-B(3) bond length is 1.60 Å. The B(2)-B(4) bond length is 1.68 Å. The B(2)-B(5) bond length is 1.80 Å. The B(2)-I(1) bond length is 2.20 Å. In the third B site, B(3) is bonded in a 4-coordinate geometry to one B(2), one B(3), and two equivalent B(4) atoms. The B(3)-B(3) bond length is 1.64 Å. There is one shorter (1.68 Å) and one longer (1.69 Å) B(3)-B(4) bond length. In the fourth B site, B(4) is bonded in a 5-coordinate geometry to one B(1), one B(2), one B(5), and two equivalent B(3) atoms. The B(4)-B(5) bond length is 1.72 Å. In the fifth B site, B(5) is bonded in a 4-coordinate geometry to one B(1), one B(2), one B(4), and one B(5) atom. The B(5)-B(5) bond length is 1.67 Å. I(1) is bonded in a water-like geometry to one B(1) and one B(2) atom.