Gd2SnS5 crystallizes in the orthorhombic Pbam space group. Gd(1) is bonded in a 8-coordinate geometry to two equivalent S(2), two equivalent S(3), and four equivalent S(1) atoms. Sn(1) is bonded to two equivalent S(1) and four equivalent S(3) atoms to form edge-sharing SnS6 octahedra. There are three inequivalent S sites. In the first S site, S(1) is bonded to four equivalent Gd(1) and one Sn(1) atom to form distorted SGd4Sn trigonal bipyramids that share corners with five equivalent S(1)Gd4Sn trigonal bipyramids, corners with four equivalent S(3)Gd2Sn2 trigonal pyramids, edges with four equivalent S(1)Gd4Sn trigonal bipyramids, and edges with four equivalent S(3)Gd2Sn2 trigonal pyramids. In the second S site, S(2) is bonded in a square co-planar geometry to four equivalent Gd(1) atoms. In the third S site, S(3) is bonded to two equivalent Gd(1) and two equivalent Sn(1) atoms to form distorted SGd2Sn2 trigonal pyramids that share corners with four equivalent S(1)Gd4Sn trigonal bipyramids, corners with six equivalent S(3)Gd2Sn2 trigonal pyramids, edges with four equivalent S(1)Gd4Sn trigonal bipyramids, and  an edgeedge with one S(3)Gd2Sn2 trigonal pyramid.
Gd2SnS5 crystallizes in the orthorhombic Pbam space group. Gd(1) is bonded in a 8-coordinate geometry to two equivalent S(2), two equivalent S(3), and four equivalent S(1) atoms. Both Gd(1)-S(2) bond lengths are 2.76 Å. There is one shorter (2.87 Å) and one longer (2.95 Å) Gd(1)-S(3) bond length. There are two shorter (2.92 Å) and two longer (3.00 Å) Gd(1)-S(1) bond lengths. Sn(1) is bonded to two equivalent S(1) and four equivalent S(3) atoms to form edge-sharing SnS6 octahedra. Both Sn(1)-S(1) bond lengths are 2.59 Å. All Sn(1)-S(3) bond lengths are 2.56 Å. There are three inequivalent S sites. In the first S site, S(1) is bonded to four equivalent Gd(1) and one Sn(1) atom to form distorted SGd4Sn trigonal bipyramids that share corners with five equivalent S(1)Gd4Sn trigonal bipyramids, corners with four equivalent S(3)Gd2Sn2 trigonal pyramids, edges with four equivalent S(1)Gd4Sn trigonal bipyramids, and edges with four equivalent S(3)Gd2Sn2 trigonal pyramids. In the second S site, S(2) is bonded in a square co-planar geometry to four equivalent Gd(1) atoms. In the third S site, S(3) is bonded to two equivalent Gd(1) and two equivalent Sn(1) atoms to form distorted SGd2Sn2 trigonal pyramids that share corners with four equivalent S(1)Gd4Sn trigonal bipyramids, corners with six equivalent S(3)Gd2Sn2 trigonal pyramids, edges with four equivalent S(1)Gd4Sn trigonal bipyramids, and  an edgeedge with one S(3)Gd2Sn2 trigonal pyramid.