CsI3 crystallizes in the orthorhombic Pnma space group. Cs(1) is bonded in a 10-coordinate geometry to two equivalent I(2), four equivalent I(1), and four equivalent I(3) atoms. There are three inequivalent I sites. In the first I site, I(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Cs(1), one I(1), and one I(3) atom. In the second I site, I(1) is bonded in a 5-coordinate geometry to four equivalent Cs(1) and one I(2) atom. In the third I site, I(3) is bonded to four equivalent Cs(1) and one I(2) atom to form a mixture of distorted edge and corner-sharing ICs4I trigonal bipyramids.
CsI3 crystallizes in the orthorhombic Pnma space group. Cs(1) is bonded in a 10-coordinate geometry to two equivalent I(2), four equivalent I(1), and four equivalent I(3) atoms. Both Cs(1)-I(2) bond lengths are 4.13 Å. There are a spread of Cs(1)-I(1) bond distances ranging from 3.85-3.96 Å. There are a spread of Cs(1)-I(3) bond distances ranging from 3.98-4.41 Å. There are three inequivalent I sites. In the first I site, I(2) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Cs(1), one I(1), and one I(3) atom. The I(2)-I(1) bond length is 3.02 Å. The I(2)-I(3) bond length is 2.89 Å. In the second I site, I(1) is bonded in a 5-coordinate geometry to four equivalent Cs(1) and one I(2) atom. In the third I site, I(3) is bonded to four equivalent Cs(1) and one I(2) atom to form a mixture of distorted edge and corner-sharing ICs4I trigonal bipyramids.