TlFeI3 crystallizes in the orthorhombic Pnma space group. Fe(1) is bonded to one I(2), two equivalent I(1), and three equivalent I(3) atoms to form edge-sharing FeI6 octahedra. Tl(1) is bonded in a 4-coordinate geometry to four equivalent I(2) atoms. There are three inequivalent I sites. In the first I site, I(1) is bonded in a water-like geometry to two equivalent Fe(1) atoms. In the second I site, I(2) is bonded in a distorted single-bond geometry to one Fe(1) and four equivalent Tl(1) atoms. In the third I site, I(3) is bonded in a distorted T-shaped geometry to three equivalent Fe(1) atoms.
TlFeI3 crystallizes in the orthorhombic Pnma space group. Fe(1) is bonded to one I(2), two equivalent I(1), and three equivalent I(3) atoms to form edge-sharing FeI6 octahedra. The Fe(1)-I(2) bond length is 2.69 Å. Both Fe(1)-I(1) bond lengths are 2.68 Å. There is one shorter (2.61 Å) and two longer (2.64 Å) Fe(1)-I(3) bond lengths. Tl(1) is bonded in a 4-coordinate geometry to four equivalent I(2) atoms. There are two shorter (3.51 Å) and two longer (3.54 Å) Tl(1)-I(2) bond lengths. There are three inequivalent I sites. In the first I site, I(1) is bonded in a water-like geometry to two equivalent Fe(1) atoms. In the second I site, I(2) is bonded in a distorted single-bond geometry to one Fe(1) and four equivalent Tl(1) atoms. In the third I site, I(3) is bonded in a distorted T-shaped geometry to three equivalent Fe(1) atoms.