HoCuS2 crystallizes in the orthorhombic Pnma space group. Ho(1) is bonded to three equivalent S(1) and three equivalent S(2) atoms to form HoS6 octahedra that share corners with four equivalent Ho(1)S6 octahedra, corners with six equivalent Cu(1)S4 tetrahedra, edges with four equivalent Ho(1)S6 octahedra, and edges with three equivalent Cu(1)S4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. Cu(1) is bonded to one S(1) and three equivalent S(2) atoms to form CuS4 tetrahedra that share corners with six equivalent Ho(1)S6 octahedra, corners with two equivalent Cu(1)S4 tetrahedra, edges with three equivalent Ho(1)S6 octahedra, and edges with two equivalent Cu(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-58°. There are two inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to three equivalent Ho(1) and one Cu(1) atom. In the second S site, S(2) is bonded to three equivalent Ho(1) and three equivalent Cu(1) atoms to form distorted edge-sharing SHo3Cu3 octahedra.
HoCuS2 crystallizes in the orthorhombic Pnma space group. Ho(1) is bonded to three equivalent S(1) and three equivalent S(2) atoms to form HoS6 octahedra that share corners with four equivalent Ho(1)S6 octahedra, corners with six equivalent Cu(1)S4 tetrahedra, edges with four equivalent Ho(1)S6 octahedra, and edges with three equivalent Cu(1)S4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There are two shorter (2.64 Å) and one longer (2.69 Å) Ho(1)-S(1) bond length. There is one shorter (2.78 Å) and two longer (2.79 Å) Ho(1)-S(2) bond lengths. Cu(1) is bonded to one S(1) and three equivalent S(2) atoms to form CuS4 tetrahedra that share corners with six equivalent Ho(1)S6 octahedra, corners with two equivalent Cu(1)S4 tetrahedra, edges with three equivalent Ho(1)S6 octahedra, and edges with two equivalent Cu(1)S4 tetrahedra. The corner-sharing octahedral tilt angles range from 14-58°. The Cu(1)-S(1) bond length is 2.29 Å. There is one shorter (2.36 Å) and two longer (2.39 Å) Cu(1)-S(2) bond lengths. There are two inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to three equivalent Ho(1) and one Cu(1) atom. In the second S site, S(2) is bonded to three equivalent Ho(1) and three equivalent Cu(1) atoms to form distorted edge-sharing SHo3Cu3 octahedra.