Nb2NiS4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 8-coordinate geometry to one S(1), two equivalent S(2), two equivalent S(4), and three equivalent S(3) atoms. In the second Nb site, Nb(2) is bonded to one S(2), two equivalent S(1), and three equivalent S(4) atoms to form distorted edge-sharing NbS6 octahedra. Ni(1) is bonded in a distorted rectangular see-saw-like geometry to one S(1), one S(4), and two equivalent S(2) atoms. There are four inequivalent S sites. In the first S site, S(1) is bonded to one Nb(1), two equivalent Nb(2), and one Ni(1) atom to form distorted corner-sharing SNb3Ni tetrahedra. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Nb(2), two equivalent Nb(1), and two equivalent Ni(1) atoms. In the third S site, S(3) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Nb(1) atoms. In the fourth S site, S(4) is bonded in a 6-coordinate geometry to two equivalent Nb(1), three equivalent Nb(2), and one Ni(1) atom.
Nb2NiS4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a 8-coordinate geometry to one S(1), two equivalent S(2), two equivalent S(4), and three equivalent S(3) atoms. The Nb(1)-S(1) bond length is 2.58 Å. Both Nb(1)-S(2) bond lengths are 2.57 Å. Both Nb(1)-S(4) bond lengths are 2.78 Å. There are two shorter (2.53 Å) and one longer (2.59 Å) Nb(1)-S(3) bond length. In the second Nb site, Nb(2) is bonded to one S(2), two equivalent S(1), and three equivalent S(4) atoms to form distorted edge-sharing NbS6 octahedra. The Nb(2)-S(2) bond length is 2.49 Å. Both Nb(2)-S(1) bond lengths are 2.49 Å. There is one shorter (2.56 Å) and two longer (2.69 Å) Nb(2)-S(4) bond lengths. Ni(1) is bonded in a distorted rectangular see-saw-like geometry to one S(1), one S(4), and two equivalent S(2) atoms. The Ni(1)-S(1) bond length is 2.27 Å. The Ni(1)-S(4) bond length is 2.28 Å. Both Ni(1)-S(2) bond lengths are 2.21 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded to one Nb(1), two equivalent Nb(2), and one Ni(1) atom to form distorted corner-sharing SNb3Ni tetrahedra. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Nb(2), two equivalent Nb(1), and two equivalent Ni(1) atoms. In the third S site, S(3) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Nb(1) atoms. In the fourth S site, S(4) is bonded in a 6-coordinate geometry to two equivalent Nb(1), three equivalent Nb(2), and one Ni(1) atom.