HfCrCuS4 crystallizes in the monoclinic Cm space group. Hf(1) is bonded to one S(1), one S(4), two equivalent S(2), and two equivalent S(3) atoms to form HfS6 octahedra that share corners with six equivalent Cu(1)S6 octahedra, edges with two equivalent Hf(1)S6 octahedra, edges with four equivalent Cr(1)S6 octahedra, and  a faceface with one Cu(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. Cr(1) is bonded to one S(2), one S(3), two equivalent S(1), and two equivalent S(4) atoms to form CrS6 octahedra that share corners with six equivalent Cu(1)S6 octahedra, edges with two equivalent Cr(1)S6 octahedra, edges with four equivalent Hf(1)S6 octahedra, and  a faceface with one Cu(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 41-50°. Cu(1) is bonded to one S(1), one S(2), two equivalent S(3), and two equivalent S(4) atoms to form distorted CuS6 octahedra that share corners with six equivalent Hf(1)S6 octahedra, corners with six equivalent Cr(1)S6 octahedra, edges with two equivalent Cu(1)S6 octahedra,  a faceface with one Hf(1)S6 octahedra, and  a faceface with one Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 41-54°. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Hf(1), two equivalent Cr(1), and one Cu(1) atom. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to two equivalent Hf(1), one Cr(1), and one Cu(1) atom. In the third S site, S(3) is bonded to two equivalent Hf(1), one Cr(1), and two equivalent Cu(1) atoms to form distorted SHf2CrCu2 square pyramids that share corners with two equivalent S(4)HfCr2Cu2 trigonal bipyramids, edges with two equivalent S(3)Hf2CrCu2 square pyramids, and edges with three equivalent S(4)HfCr2Cu2 trigonal bipyramids. In the fourth S site, S(4) is bonded to one Hf(1), two equivalent Cr(1), and two equivalent Cu(1) atoms to form distorted SHfCr2Cu2 trigonal bipyramids that share corners with two equivalent S(3)Hf2CrCu2 square pyramids, edges with three equivalent S(3)Hf2CrCu2 square pyramids, and edges with two equivalent S(4)HfCr2Cu2 trigonal bipyramids.
HfCrCuS4 crystallizes in the monoclinic Cm space group. Hf(1) is bonded to one S(1), one S(4), two equivalent S(2), and two equivalent S(3) atoms to form HfS6 octahedra that share corners with six equivalent Cu(1)S6 octahedra, edges with two equivalent Hf(1)S6 octahedra, edges with four equivalent Cr(1)S6 octahedra, and  a faceface with one Cu(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. The Hf(1)-S(1) bond length is 2.52 Å. The Hf(1)-S(4) bond length is 2.56 Å. Both Hf(1)-S(2) bond lengths are 2.51 Å. Both Hf(1)-S(3) bond lengths are 2.57 Å. Cr(1) is bonded to one S(2), one S(3), two equivalent S(1), and two equivalent S(4) atoms to form CrS6 octahedra that share corners with six equivalent Cu(1)S6 octahedra, edges with two equivalent Cr(1)S6 octahedra, edges with four equivalent Hf(1)S6 octahedra, and  a faceface with one Cu(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 41-50°. The Cr(1)-S(2) bond length is 2.46 Å. The Cr(1)-S(3) bond length is 2.44 Å. Both Cr(1)-S(1) bond lengths are 2.44 Å. Both Cr(1)-S(4) bond lengths are 2.47 Å. Cu(1) is bonded to one S(1), one S(2), two equivalent S(3), and two equivalent S(4) atoms to form distorted CuS6 octahedra that share corners with six equivalent Hf(1)S6 octahedra, corners with six equivalent Cr(1)S6 octahedra, edges with two equivalent Cu(1)S6 octahedra,  a faceface with one Hf(1)S6 octahedra, and  a faceface with one Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 41-54°. The Cu(1)-S(1) bond length is 2.40 Å. The Cu(1)-S(2) bond length is 2.46 Å. Both Cu(1)-S(3) bond lengths are 2.64 Å. Both Cu(1)-S(4) bond lengths are 2.53 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Hf(1), two equivalent Cr(1), and one Cu(1) atom. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to two equivalent Hf(1), one Cr(1), and one Cu(1) atom. In the third S site, S(3) is bonded to two equivalent Hf(1), one Cr(1), and two equivalent Cu(1) atoms to form distorted SHf2CrCu2 square pyramids that share corners with two equivalent S(4)HfCr2Cu2 trigonal bipyramids, edges with two equivalent S(3)Hf2CrCu2 square pyramids, and edges with three equivalent S(4)HfCr2Cu2 trigonal bipyramids. In the fourth S site, S(4) is bonded to one Hf(1), two equivalent Cr(1), and two equivalent Cu(1) atoms to form distorted SHfCr2Cu2 trigonal bipyramids that share corners with two equivalent S(3)Hf2CrCu2 square pyramids, edges with three equivalent S(3)Hf2CrCu2 square pyramids, and edges with two equivalent S(4)HfCr2Cu2 trigonal bipyramids.