CsZrCuSe3 crystallizes in the orthorhombic Cmcm space group. Cs(1) is bonded in a 8-coordinate geometry to two equivalent Se(2) and six equivalent Se(1) atoms. Zr(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form ZrSe6 octahedra that share corners with two equivalent Zr(1)Se6 octahedra, edges with two equivalent Zr(1)Se6 octahedra, and edges with four equivalent Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 42°. Cu(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form CuSe4 tetrahedra that share corners with two equivalent Cu(1)Se4 tetrahedra and edges with four equivalent Zr(1)Se6 octahedra. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to three equivalent Cs(1), two equivalent Zr(1), and one Cu(1) atom. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Zr(1), and two equivalent Cu(1) atoms.
CsZrCuSe3 crystallizes in the orthorhombic Cmcm space group. Cs(1) is bonded in a 8-coordinate geometry to two equivalent Se(2) and six equivalent Se(1) atoms. Both Cs(1)-Se(2) bond lengths are 3.62 Å. There are four shorter (3.66 Å) and two longer (3.80 Å) Cs(1)-Se(1) bond lengths. Zr(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form ZrSe6 octahedra that share corners with two equivalent Zr(1)Se6 octahedra, edges with two equivalent Zr(1)Se6 octahedra, and edges with four equivalent Cu(1)Se4 tetrahedra. The corner-sharing octahedral tilt angles are 42°. Both Zr(1)-Se(2) bond lengths are 2.75 Å. All Zr(1)-Se(1) bond lengths are 2.74 Å. Cu(1) is bonded to two equivalent Se(1) and two equivalent Se(2) atoms to form CuSe4 tetrahedra that share corners with two equivalent Cu(1)Se4 tetrahedra and edges with four equivalent Zr(1)Se6 octahedra. Both Cu(1)-Se(1) bond lengths are 2.43 Å. Both Cu(1)-Se(2) bond lengths are 2.47 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to three equivalent Cs(1), two equivalent Zr(1), and one Cu(1) atom. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Zr(1), and two equivalent Cu(1) atoms.