Li3CuS2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form a mixture of distorted edge and corner-sharing LiS4 tetrahedra. In the second Li site, Li(2) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form a mixture of distorted edge and corner-sharing LiS4 tetrahedra. In the third Li site, Li(3) is bonded in a 5-coordinate geometry to two equivalent Cu(1), one S(1), and two equivalent S(2) atoms. Cu(1) is bonded in a 2-coordinate geometry to two equivalent Li(3), one S(1), and one S(2) atom. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Li(3), two equivalent Li(1), two equivalent Li(2), and one Cu(1) atom to form distorted SLi5Cu octahedra that share corners with two equivalent S(1)Li5Cu octahedra, corners with five equivalent S(2)Li6Cu pentagonal bipyramids,  an edgeedge with one S(1)Li5Cu octahedra, and edges with three equivalent S(2)Li6Cu pentagonal bipyramids. The corner-sharing octahedral tilt angles are 68°. In the second S site, S(2) is bonded to two equivalent Li(1), two equivalent Li(2), two equivalent Li(3), and one Cu(1) atom to form distorted SLi6Cu pentagonal bipyramids that share corners with five equivalent S(1)Li5Cu octahedra, corners with two equivalent S(2)Li6Cu pentagonal bipyramids, edges with three equivalent S(1)Li5Cu octahedra, and edges with two equivalent S(2)Li6Cu pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 15-75°.
Li3CuS2 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Li sites. In the first Li site, Li(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form a mixture of distorted edge and corner-sharing LiS4 tetrahedra. There is one shorter (2.41 Å) and one longer (2.44 Å) Li(1)-S(1) bond length. There is one shorter (2.58 Å) and one longer (2.59 Å) Li(1)-S(2) bond length. In the second Li site, Li(2) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form a mixture of distorted edge and corner-sharing LiS4 tetrahedra. There is one shorter (2.42 Å) and one longer (2.47 Å) Li(2)-S(1) bond length. There is one shorter (2.48 Å) and one longer (2.52 Å) Li(2)-S(2) bond length. In the third Li site, Li(3) is bonded in a 5-coordinate geometry to two equivalent Cu(1), one S(1), and two equivalent S(2) atoms. There is one shorter (2.62 Å) and one longer (2.97 Å) Li(3)-Cu(1) bond length. The Li(3)-S(1) bond length is 2.38 Å. There is one shorter (2.50 Å) and one longer (2.59 Å) Li(3)-S(2) bond length. Cu(1) is bonded in a 2-coordinate geometry to two equivalent Li(3), one S(1), and one S(2) atom. The Cu(1)-S(1) bond length is 2.15 Å. The Cu(1)-S(2) bond length is 2.16 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to one Li(3), two equivalent Li(1), two equivalent Li(2), and one Cu(1) atom to form distorted SLi5Cu octahedra that share corners with two equivalent S(1)Li5Cu octahedra, corners with five equivalent S(2)Li6Cu pentagonal bipyramids,  an edgeedge with one S(1)Li5Cu octahedra, and edges with three equivalent S(2)Li6Cu pentagonal bipyramids. The corner-sharing octahedral tilt angles are 68°. In the second S site, S(2) is bonded to two equivalent Li(1), two equivalent Li(2), two equivalent Li(3), and one Cu(1) atom to form distorted SLi6Cu pentagonal bipyramids that share corners with five equivalent S(1)Li5Cu octahedra, corners with two equivalent S(2)Li6Cu pentagonal bipyramids, edges with three equivalent S(1)Li5Cu octahedra, and edges with two equivalent S(2)Li6Cu pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 15-75°.