SrCu2SnS4 crystallizes in the trigonal P3_221 space group. Sr(1) is bonded in a 8-coordinate geometry to four equivalent S(1) and four equivalent S(2) atoms. Cu(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Cu(1)S4 tetrahedra and corners with four equivalent Sn(1)S4 tetrahedra. Sn(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form SnS4 tetrahedra that share corners with eight equivalent Cu(1)S4 tetrahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Sr(1), two equivalent Cu(1), and one Sn(1) atom to form a mixture of distorted edge and corner-sharing SSr2Cu2Sn trigonal bipyramids. In the second S site, S(2) is bonded in a 5-coordinate geometry to two equivalent Sr(1), two equivalent Cu(1), and one Sn(1) atom.
SrCu2SnS4 crystallizes in the trigonal P3_221 space group. Sr(1) is bonded in a 8-coordinate geometry to four equivalent S(1) and four equivalent S(2) atoms. There are two shorter (3.11 Å) and two longer (3.23 Å) Sr(1)-S(1) bond lengths. There are two shorter (3.15 Å) and two longer (3.35 Å) Sr(1)-S(2) bond lengths. Cu(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form distorted CuS4 tetrahedra that share corners with four equivalent Cu(1)S4 tetrahedra and corners with four equivalent Sn(1)S4 tetrahedra. There is one shorter (2.31 Å) and one longer (2.34 Å) Cu(1)-S(1) bond length. There is one shorter (2.29 Å) and one longer (2.35 Å) Cu(1)-S(2) bond length. Sn(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form SnS4 tetrahedra that share corners with eight equivalent Cu(1)S4 tetrahedra. Both Sn(1)-S(1) bond lengths are 2.45 Å. Both Sn(1)-S(2) bond lengths are 2.44 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Sr(1), two equivalent Cu(1), and one Sn(1) atom to form a mixture of distorted edge and corner-sharing SSr2Cu2Sn trigonal bipyramids. In the second S site, S(2) is bonded in a 5-coordinate geometry to two equivalent Sr(1), two equivalent Cu(1), and one Sn(1) atom.