CsCeCdSe3 crystallizes in the orthorhombic Cmcm space group. Cs(1) is bonded in a 8-coordinate geometry to two equivalent Se(1) and six equivalent Se(2) atoms. Ce(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form CeSe6 octahedra that share corners with two equivalent Ce(1)Se6 octahedra, edges with two equivalent Ce(1)Se6 octahedra, and edges with four equivalent Cd(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. Cd(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form CdSe4 tetrahedra that share corners with two equivalent Cd(1)Se4 tetrahedra and edges with four equivalent Ce(1)Se6 octahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Ce(1), and two equivalent Cd(1) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Cs(1), two equivalent Ce(1), and one Cd(1) atom.
CsCeCdSe3 crystallizes in the orthorhombic Cmcm space group. Cs(1) is bonded in a 8-coordinate geometry to two equivalent Se(1) and six equivalent Se(2) atoms. Both Cs(1)-Se(1) bond lengths are 3.70 Å. There are four shorter (3.88 Å) and two longer (4.02 Å) Cs(1)-Se(2) bond lengths. Ce(1) is bonded to two equivalent Se(1) and four equivalent Se(2) atoms to form CeSe6 octahedra that share corners with two equivalent Ce(1)Se6 octahedra, edges with two equivalent Ce(1)Se6 octahedra, and edges with four equivalent Cd(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. Both Ce(1)-Se(1) bond lengths are 3.05 Å. All Ce(1)-Se(2) bond lengths are 3.02 Å. Cd(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form CdSe4 tetrahedra that share corners with two equivalent Cd(1)Se4 tetrahedra and edges with four equivalent Ce(1)Se6 octahedra. Both Cd(1)-Se(1) bond lengths are 2.74 Å. Both Cd(1)-Se(2) bond lengths are 2.63 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Ce(1), and two equivalent Cd(1) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Cs(1), two equivalent Ce(1), and one Cd(1) atom.