KCuHfS3 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded in a 8-coordinate geometry to two equivalent S(2) and six equivalent S(1) atoms. Hf(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form HfS6 octahedra that share corners with two equivalent Hf(1)S6 octahedra, edges with two equivalent Hf(1)S6 octahedra, and edges with four equivalent Cu(1)S4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. Cu(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form CuS4 tetrahedra that share corners with two equivalent Cu(1)S4 tetrahedra and edges with four equivalent Hf(1)S6 octahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to three equivalent K(1), two equivalent Hf(1), and one Cu(1) atom. In the second S site, S(2) is bonded in a 6-coordinate geometry to two equivalent K(1), two equivalent Hf(1), and two equivalent Cu(1) atoms.
KCuHfS3 crystallizes in the orthorhombic Cmcm space group. K(1) is bonded in a 8-coordinate geometry to two equivalent S(2) and six equivalent S(1) atoms. Both K(1)-S(2) bond lengths are 3.21 Å. There are four shorter (3.32 Å) and two longer (3.45 Å) K(1)-S(1) bond lengths. Hf(1) is bonded to two equivalent S(2) and four equivalent S(1) atoms to form HfS6 octahedra that share corners with two equivalent Hf(1)S6 octahedra, edges with two equivalent Hf(1)S6 octahedra, and edges with four equivalent Cu(1)S4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. Both Hf(1)-S(2) bond lengths are 2.60 Å. All Hf(1)-S(1) bond lengths are 2.58 Å. Cu(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form CuS4 tetrahedra that share corners with two equivalent Cu(1)S4 tetrahedra and edges with four equivalent Hf(1)S6 octahedra. Both Cu(1)-S(1) bond lengths are 2.29 Å. Both Cu(1)-S(2) bond lengths are 2.33 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to three equivalent K(1), two equivalent Hf(1), and one Cu(1) atom. In the second S site, S(2) is bonded in a 6-coordinate geometry to two equivalent K(1), two equivalent Hf(1), and two equivalent Cu(1) atoms.