NiCr2S4 crystallizes in the monoclinic C2/m space group. Cr(1) is bonded to three equivalent S(1) and three equivalent S(2) atoms to form distorted CrS6 octahedra that share corners with six equivalent Ni(1)S6 octahedra, edges with six equivalent Cr(1)S6 octahedra, and  a faceface with one Ni(1)S6 octahedra. The corner-sharing octahedral tilt angles are 53°. Ni(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form NiS6 octahedra that share corners with twelve equivalent Cr(1)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, and faces with two equivalent Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles are 53°. There are two inequivalent S sites. In the first S site, S(2) is bonded in a 5-coordinate geometry to three equivalent Cr(1) and two equivalent Ni(1) atoms. In the second S site, S(1) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Cr(1) and one Ni(1) atom.
NiCr2S4 crystallizes in the monoclinic C2/m space group. Cr(1) is bonded to three equivalent S(1) and three equivalent S(2) atoms to form distorted CrS6 octahedra that share corners with six equivalent Ni(1)S6 octahedra, edges with six equivalent Cr(1)S6 octahedra, and  a faceface with one Ni(1)S6 octahedra. The corner-sharing octahedral tilt angles are 53°. There is one shorter (2.24 Å) and two longer (2.26 Å) Cr(1)-S(1) bond lengths. There are two shorter (2.41 Å) and one longer (2.45 Å) Cr(1)-S(2) bond length. Ni(1) is bonded to two equivalent S(1) and four equivalent S(2) atoms to form NiS6 octahedra that share corners with twelve equivalent Cr(1)S6 octahedra, edges with two equivalent Ni(1)S6 octahedra, and faces with two equivalent Cr(1)S6 octahedra. The corner-sharing octahedral tilt angles are 53°. Both Ni(1)-S(1) bond lengths are 2.31 Å. All Ni(1)-S(2) bond lengths are 2.37 Å. There are two inequivalent S sites. In the first S site, S(2) is bonded in a 5-coordinate geometry to three equivalent Cr(1) and two equivalent Ni(1) atoms. In the second S site, S(1) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Cr(1) and one Ni(1) atom.