Dy3GaS6 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded to one S(3), two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms to form distorted DyS7 pentagonal bipyramids that share corners with four equivalent Dy(1)S7 pentagonal bipyramids, corners with three equivalent Ga(1)S4 tetrahedra, edges with two equivalent Dy(1)S7 pentagonal bipyramids,  an edgeedge with one Ga(1)S4 tetrahedra, and  a faceface with one Dy(1)S7 pentagonal bipyramid. In the second Dy site, Dy(2) is bonded in a 7-coordinate geometry to one S(3), two equivalent S(1), and four equivalent S(2) atoms. Ga(1) is bonded to one S(3), one S(4), and two equivalent S(1) atoms to form GaS4 tetrahedra that share corners with six equivalent Dy(1)S7 pentagonal bipyramids and edges with two equivalent Dy(1)S7 pentagonal bipyramids. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Dy(2), two equivalent Dy(1), and one Ga(1) atom. In the second S site, S(2) is bonded to two equivalent Dy(1) and two equivalent Dy(2) atoms to form SDy4 tetrahedra that share corners with two equivalent S(2)Dy4 tetrahedra, corners with four equivalent S(3)Dy3Ga tetrahedra, corners with two equivalent S(4)Dy4Ga trigonal bipyramids, edges with three equivalent S(2)Dy4 tetrahedra, and  an edgeedge with one S(4)Dy4Ga trigonal bipyramid. In the third S site, S(3) is bonded to one Dy(2), two equivalent Dy(1), and one Ga(1) atom to form distorted SDy3Ga tetrahedra that share corners with eight equivalent S(2)Dy4 tetrahedra,  a cornercorner with one S(4)Dy4Ga trigonal bipyramid, and edges with two equivalent S(4)Dy4Ga trigonal bipyramids. In the fourth S site, S(4) is bonded to four equivalent Dy(1) and one Ga(1) atom to form distorted SDy4Ga trigonal bipyramids that share  a cornercorner with one S(3)Dy3Ga tetrahedra, corners with four equivalent S(2)Dy4 tetrahedra, edges with two equivalent S(3)Dy3Ga tetrahedra, edges with two equivalent S(2)Dy4 tetrahedra, and edges with two equivalent S(4)Dy4Ga trigonal bipyramids.
Dy3GaS6 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Dy sites. In the first Dy site, Dy(1) is bonded to one S(3), two equivalent S(1), two equivalent S(2), and two equivalent S(4) atoms to form distorted DyS7 pentagonal bipyramids that share corners with four equivalent Dy(1)S7 pentagonal bipyramids, corners with three equivalent Ga(1)S4 tetrahedra, edges with two equivalent Dy(1)S7 pentagonal bipyramids,  an edgeedge with one Ga(1)S4 tetrahedra, and  a faceface with one Dy(1)S7 pentagonal bipyramid. The Dy(1)-S(3) bond length is 2.78 Å. There is one shorter (2.75 Å) and one longer (2.89 Å) Dy(1)-S(1) bond length. There is one shorter (2.67 Å) and one longer (2.71 Å) Dy(1)-S(2) bond length. Both Dy(1)-S(4) bond lengths are 2.95 Å. In the second Dy site, Dy(2) is bonded in a 7-coordinate geometry to one S(3), two equivalent S(1), and four equivalent S(2) atoms. The Dy(2)-S(3) bond length is 3.03 Å. Both Dy(2)-S(1) bond lengths are 2.81 Å. There are two shorter (2.72 Å) and two longer (2.77 Å) Dy(2)-S(2) bond lengths. Ga(1) is bonded to one S(3), one S(4), and two equivalent S(1) atoms to form GaS4 tetrahedra that share corners with six equivalent Dy(1)S7 pentagonal bipyramids and edges with two equivalent Dy(1)S7 pentagonal bipyramids. The Ga(1)-S(3) bond length is 2.26 Å. The Ga(1)-S(4) bond length is 2.32 Å. Both Ga(1)-S(1) bond lengths are 2.28 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a rectangular see-saw-like geometry to one Dy(2), two equivalent Dy(1), and one Ga(1) atom. In the second S site, S(2) is bonded to two equivalent Dy(1) and two equivalent Dy(2) atoms to form SDy4 tetrahedra that share corners with two equivalent S(2)Dy4 tetrahedra, corners with four equivalent S(3)Dy3Ga tetrahedra, corners with two equivalent S(4)Dy4Ga trigonal bipyramids, edges with three equivalent S(2)Dy4 tetrahedra, and  an edgeedge with one S(4)Dy4Ga trigonal bipyramid. In the third S site, S(3) is bonded to one Dy(2), two equivalent Dy(1), and one Ga(1) atom to form distorted SDy3Ga tetrahedra that share corners with eight equivalent S(2)Dy4 tetrahedra,  a cornercorner with one S(4)Dy4Ga trigonal bipyramid, and edges with two equivalent S(4)Dy4Ga trigonal bipyramids. In the fourth S site, S(4) is bonded to four equivalent Dy(1) and one Ga(1) atom to form distorted SDy4Ga trigonal bipyramids that share  a cornercorner with one S(3)Dy3Ga tetrahedra, corners with four equivalent S(2)Dy4 tetrahedra, edges with two equivalent S(3)Dy3Ga tetrahedra, edges with two equivalent S(2)Dy4 tetrahedra, and edges with two equivalent S(4)Dy4Ga trigonal bipyramids.