Cr5NiS8 crystallizes in the triclinic P-1 space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one S(1), one S(4), two equivalent S(2), and two equivalent S(3) atoms to form CrS6 octahedra that share corners with two equivalent Cr(3)S6 octahedra, corners with four equivalent Ni(1)S6 octahedra, edges with two equivalent Cr(1)S6 octahedra, edges with four equivalent Cr(2)S6 octahedra, and  a faceface with one Cr(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. In the second Cr site, Cr(2) 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 two equivalent Ni(1)S6 octahedra, corners with four equivalent Cr(3)S6 octahedra, edges with two equivalent Cr(2)S6 octahedra, edges with four equivalent Cr(1)S6 octahedra, and  a faceface with one Ni(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. In the third Cr site, Cr(3) is bonded to two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms to form CrS6 octahedra that share corners with four equivalent Cr(1)S6 octahedra, corners with eight equivalent Cr(2)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 range from 48-54°. Ni(1) is bonded to two equivalent S(1), two equivalent S(3), and two equivalent S(4) atoms to form NiS6 octahedra that share corners with four equivalent Cr(2)S6 octahedra, corners with eight equivalent Cr(1)S6 octahedra, edges with two equivalent Cr(3)S6 octahedra, and faces with two equivalent Cr(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Cr(1), two equivalent Cr(2), and one Ni(1) atom. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Cr(2), one Cr(3), and two equivalent Cr(1) atoms. In the third S site, S(3) is bonded to one Cr(2), one Cr(3), two equivalent Cr(1), and one Ni(1) atom to form a mixture of distorted corner and edge-sharing SCr4Ni trigonal bipyramids. In the fourth S site, S(4) is bonded to one Cr(1), one Cr(3), two equivalent Cr(2), and one Ni(1) atom to form a mixture of distorted corner and edge-sharing SCr4Ni trigonal bipyramids.
Cr5NiS8 crystallizes in the triclinic P-1 space group. There are three inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to one S(1), one S(4), two equivalent S(2), and two equivalent S(3) atoms to form CrS6 octahedra that share corners with two equivalent Cr(3)S6 octahedra, corners with four equivalent Ni(1)S6 octahedra, edges with two equivalent Cr(1)S6 octahedra, edges with four equivalent Cr(2)S6 octahedra, and  a faceface with one Cr(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 48-53°. The Cr(1)-S(1) bond length is 2.33 Å. The Cr(1)-S(4) bond length is 2.47 Å. There is one shorter (2.38 Å) and one longer (2.39 Å) Cr(1)-S(2) bond length. There is one shorter (2.40 Å) and one longer (2.43 Å) Cr(1)-S(3) bond length. In the second Cr site, Cr(2) 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 two equivalent Ni(1)S6 octahedra, corners with four equivalent Cr(3)S6 octahedra, edges with two equivalent Cr(2)S6 octahedra, edges with four equivalent Cr(1)S6 octahedra, and  a faceface with one Ni(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 49-54°. The Cr(2)-S(2) bond length is 2.32 Å. The Cr(2)-S(3) bond length is 2.49 Å. There is one shorter (2.34 Å) and one longer (2.35 Å) Cr(2)-S(1) bond length. There is one shorter (2.45 Å) and one longer (2.47 Å) Cr(2)-S(4) bond length. In the third Cr site, Cr(3) is bonded to two equivalent S(2), two equivalent S(3), and two equivalent S(4) atoms to form CrS6 octahedra that share corners with four equivalent Cr(1)S6 octahedra, corners with eight equivalent Cr(2)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 range from 48-54°. Both Cr(3)-S(2) bond lengths are 2.40 Å. Both Cr(3)-S(3) bond lengths are 2.44 Å. Both Cr(3)-S(4) bond lengths are 2.41 Å. Ni(1) is bonded to two equivalent S(1), two equivalent S(3), and two equivalent S(4) atoms to form NiS6 octahedra that share corners with four equivalent Cr(2)S6 octahedra, corners with eight equivalent Cr(1)S6 octahedra, edges with two equivalent Cr(3)S6 octahedra, and faces with two equivalent Cr(2)S6 octahedra. The corner-sharing octahedral tilt angles range from 49-53°. Both Ni(1)-S(1) bond lengths are 2.38 Å. Both Ni(1)-S(3) bond lengths are 2.41 Å. Both Ni(1)-S(4) bond lengths are 2.42 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 Cr(1), two equivalent Cr(2), and one Ni(1) atom. In the second S site, S(2) is bonded in a rectangular see-saw-like geometry to one Cr(2), one Cr(3), and two equivalent Cr(1) atoms. In the third S site, S(3) is bonded to one Cr(2), one Cr(3), two equivalent Cr(1), and one Ni(1) atom to form a mixture of distorted corner and edge-sharing SCr4Ni trigonal bipyramids. In the fourth S site, S(4) is bonded to one Cr(1), one Cr(3), two equivalent Cr(2), and one Ni(1) atom to form a mixture of distorted corner and edge-sharing SCr4Ni trigonal bipyramids.