CsSmI3 crystallizes in the orthorhombic Cmcm space group. Cs(1) is bonded in a 8-coordinate geometry to two equivalent I(2) and six equivalent I(1) atoms. Sm(1) is bonded to two equivalent I(2) and four equivalent I(1) atoms to form a mixture of corner and edge-sharing SmI6 octahedra. The corner-sharing octahedral tilt angles are 38°. There are two inequivalent I sites. In the first I site, I(1) is bonded in a 5-coordinate geometry to three equivalent Cs(1) and two equivalent Sm(1) atoms. In the second I site, I(2) is bonded in a 4-coordinate geometry to two equivalent Cs(1) and two equivalent Sm(1) atoms.
CsSmI3 crystallizes in the orthorhombic Cmcm space group. Cs(1) is bonded in a 8-coordinate geometry to two equivalent I(2) and six equivalent I(1) atoms. Both Cs(1)-I(2) bond lengths are 3.93 Å. There are four shorter (3.88 Å) and two longer (4.12 Å) Cs(1)-I(1) bond lengths. Sm(1) is bonded to two equivalent I(2) and four equivalent I(1) atoms to form a mixture of corner and edge-sharing SmI6 octahedra. The corner-sharing octahedral tilt angles are 38°. Both Sm(1)-I(2) bond lengths are 3.18 Å. All Sm(1)-I(1) bond lengths are 3.18 Å. There are two inequivalent I sites. In the first I site, I(1) is bonded in a 5-coordinate geometry to three equivalent Cs(1) and two equivalent Sm(1) atoms. In the second I site, I(2) is bonded in a 4-coordinate geometry to two equivalent Cs(1) and two equivalent Sm(1) atoms.