CsI4 crystallizes in the monoclinic P2_1/c space group. Cs(1) is bonded in a 11-coordinate geometry to two equivalent I(3), three equivalent I(1), three equivalent I(2), and three equivalent I(4) atoms. There are four inequivalent I sites. In the first I site, I(1) is bonded to three equivalent Cs(1), one I(2), and one I(3) atom to form a mixture of distorted corner and edge-sharing ICs3I2 trigonal bipyramids. In the second I site, I(2) is bonded in a 5-coordinate geometry to three equivalent Cs(1), one I(1), and one I(2) atom. In the third I site, I(3) is bonded in a 4-coordinate geometry to two equivalent Cs(1), one I(1), and one I(4) atom. In the fourth I site, I(4) is bonded in a 4-coordinate geometry to three equivalent Cs(1) and one I(3) atom.
CsI4 crystallizes in the monoclinic P2_1/c space group. Cs(1) is bonded in a 11-coordinate geometry to two equivalent I(3), three equivalent I(1), three equivalent I(2), and three equivalent I(4) atoms. There is one shorter (4.06 Å) and one longer (4.41 Å) Cs(1)-I(3) bond length. There are a spread of Cs(1)-I(1) bond distances ranging from 4.09-4.11 Å. There are a spread of Cs(1)-I(2) bond distances ranging from 4.04-4.30 Å. There are a spread of Cs(1)-I(4) bond distances ranging from 3.89-4.01 Å. There are four inequivalent I sites. In the first I site, I(1) is bonded to three equivalent Cs(1), one I(2), and one I(3) atom to form a mixture of distorted corner and edge-sharing ICs3I2 trigonal bipyramids. The I(1)-I(2) bond length is 3.37 Å. The I(1)-I(3) bond length is 3.03 Å. In the second I site, I(2) is bonded in a 5-coordinate geometry to three equivalent Cs(1), one I(1), and one I(2) atom. The I(2)-I(2) bond length is 2.81 Å. In the third I site, I(3) is bonded in a 4-coordinate geometry to two equivalent Cs(1), one I(1), and one I(4) atom. The I(3)-I(4) bond length is 2.88 Å. In the fourth I site, I(4) is bonded in a 4-coordinate geometry to three equivalent Cs(1) and one I(3) atom.