KCaI3 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded in a 8-coordinate geometry to two equivalent I(2) and six equivalent I(1) atoms. Ca(1) is bonded to two equivalent I(2) and four equivalent I(1) atoms to form a mixture of corner and edge-sharing CaI6 octahedra. The corner-sharing octahedral tilt angles are 42°. There are two inequivalent I sites. In the first I site, I(1) is bonded in a 5-coordinate geometry to three equivalent K(1) and two equivalent Ca(1) atoms. In the second I site, I(2) is bonded to two equivalent K(1) and two equivalent Ca(1) atoms to form distorted corner-sharing IK2Ca2 tetrahedra.
KCaI3 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded in a 8-coordinate geometry to two equivalent I(2) and six equivalent I(1) atoms. Both K(1)-I(2) bond lengths are 3.52 Å. There are four shorter (3.65 Å) and two longer (3.99 Å) K(1)-I(1) bond lengths. Ca(1) is bonded to two equivalent I(2) and four equivalent I(1) atoms to form a mixture of corner and edge-sharing CaI6 octahedra. The corner-sharing octahedral tilt angles are 42°. Both Ca(1)-I(2) bond lengths are 3.14 Å. All Ca(1)-I(1) bond lengths are 3.16 Å. There are two inequivalent I sites. In the first I site, I(1) is bonded in a 5-coordinate geometry to three equivalent K(1) and two equivalent Ca(1) atoms. In the second I site, I(2) is bonded to two equivalent K(1) and two equivalent Ca(1) atoms to form distorted corner-sharing IK2Ca2 tetrahedra.