Nb2CuS4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one S(2), two equivalent S(4), and three equivalent S(1) atoms to form edge-sharing NbS6 octahedra. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one S(4), two equivalent S(2), and three equivalent S(3) atoms. Cu(1) is bonded in a distorted trigonal non-coplanar geometry to one S(4) and two equivalent S(2) atoms. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 3-coordinate geometry to three equivalent Nb(1) atoms. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Nb(1), two equivalent Nb(2), and two equivalent Cu(1) atoms. In the third S site, S(3) is bonded in a distorted T-shaped geometry to three equivalent Nb(2) atoms. In the fourth S site, S(4) is bonded to one Nb(2), two equivalent Nb(1), and one Cu(1) atom to form distorted corner-sharing SNb3Cu tetrahedra.
Nb2CuS4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one S(2), two equivalent S(4), and three equivalent S(1) atoms to form edge-sharing NbS6 octahedra. The Nb(1)-S(2) bond length is 2.72 Å. Both Nb(1)-S(4) bond lengths are 2.53 Å. There is one shorter (2.43 Å) and two longer (2.45 Å) Nb(1)-S(1) bond lengths. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to one S(4), two equivalent S(2), and three equivalent S(3) atoms. The Nb(2)-S(4) bond length is 2.64 Å. Both Nb(2)-S(2) bond lengths are 2.66 Å. There is one shorter (2.42 Å) and two longer (2.43 Å) Nb(2)-S(3) bond lengths. Cu(1) is bonded in a distorted trigonal non-coplanar geometry to one S(4) and two equivalent S(2) atoms. The Cu(1)-S(4) bond length is 2.31 Å. Both Cu(1)-S(2) bond lengths are 2.32 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 3-coordinate geometry to three equivalent Nb(1) atoms. In the second S site, S(2) is bonded in a 5-coordinate geometry to one Nb(1), two equivalent Nb(2), and two equivalent Cu(1) atoms. In the third S site, S(3) is bonded in a distorted T-shaped geometry to three equivalent Nb(2) atoms. In the fourth S site, S(4) is bonded to one Nb(2), two equivalent Nb(1), and one Cu(1) atom to form distorted corner-sharing SNb3Cu tetrahedra.