NiS2 is Marcasite structured and crystallizes in the orthorhombic Pnnm space group. Ni(1) is bonded to six equivalent S(1) atoms to form NiS6 octahedra that share corners with eight equivalent Ni(1)S6 octahedra, corners with six equivalent S(1)Ni3S tetrahedra, and edges with two equivalent Ni(1)S6 octahedra. The corner-sharing octahedral tilt angles are 63°. S(1) is bonded to three equivalent Ni(1) and one S(1) atom to form SNi3S tetrahedra that share corners with three equivalent Ni(1)S6 octahedra, corners with thirteen equivalent S(1)Ni3S tetrahedra, and  an edgeedge with one S(1)Ni3S tetrahedra. The corner-sharing octahedral tilt angles range from 71-73°.
NiS2 is Marcasite structured and crystallizes in the orthorhombic Pnnm space group. Ni(1) is bonded to six equivalent S(1) atoms to form NiS6 octahedra that share corners with eight equivalent Ni(1)S6 octahedra, corners with six equivalent S(1)Ni3S tetrahedra, and edges with two equivalent Ni(1)S6 octahedra. The corner-sharing octahedral tilt angles are 63°. There are two shorter (2.37 Å) and four longer (2.40 Å) Ni(1)-S(1) bond lengths. S(1) is bonded to three equivalent Ni(1) and one S(1) atom to form SNi3S tetrahedra that share corners with three equivalent Ni(1)S6 octahedra, corners with thirteen equivalent S(1)Ni3S tetrahedra, and  an edgeedge with one S(1)Ni3S tetrahedra. The corner-sharing octahedral tilt angles range from 71-73°. The S(1)-S(1) bond length is 2.08 Å.