In2Sn3S7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent In sites. In the first In site, In(1) is bonded to one S(4), two equivalent S(5), and three equivalent S(6) atoms to form InS6 octahedra that share corners with two equivalent Sn(1)S6 octahedra,  a cornercorner with one Sn(2)S6 pentagonal pyramid, edges with two equivalent In(2)S6 octahedra, and edges with four equivalent In(1)S6 octahedra. The corner-sharing octahedral tilt angles are 58°. In the second In site, In(2) is bonded to one S(5), two equivalent S(4), and three equivalent S(2) atoms to form InS6 octahedra that share  a cornercorner with one Sn(1)S6 octahedra, corners with two equivalent Sn(2)S6 pentagonal pyramids, edges with two equivalent In(1)S6 octahedra, edges with four equivalent In(2)S6 octahedra, and edges with three equivalent Sn(2)S6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 54°. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one S(5), two equivalent S(3), and three equivalent S(1) atoms to form SnS6 octahedra that share  a cornercorner with one In(2)S6 octahedra, corners with two equivalent In(1)S6 octahedra, and edges with four equivalent Sn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 54-58°. In the second Sn site, Sn(2) is bonded to one S(4), two equivalent S(2), and three equivalent S(7) atoms to form distorted SnS6 pentagonal pyramids that share  a cornercorner with one In(1)S6 octahedra, corners with two equivalent In(2)S6 octahedra, edges with three equivalent In(2)S6 octahedra, and edges with four equivalent Sn(2)S6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 10-19°. In the third Sn site, Sn(3) is bonded in a 3-coordinate geometry to one S(3), one S(4), and two equivalent S(7) atoms. There are seven inequivalent S sites. In the first S site, S(1) is bonded in a distorted T-shaped geometry to three equivalent Sn(1) atoms. In the second S site, S(2) is bonded to three equivalent In(2) and two equivalent Sn(2) atoms to form distorted SIn3Sn2 square pyramids that share corners with four equivalent S(7)Sn5 trigonal bipyramids, edges with four equivalent S(2)In3Sn2 square pyramids, and  an edgeedge with one S(7)Sn5 trigonal bipyramid. In the third S site, S(3) is bonded in a trigonal non-coplanar geometry to one Sn(3) and two equivalent Sn(1) atoms. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to one In(1), two equivalent In(2), one Sn(2), and one Sn(3) atom. In the fifth S site, S(5) is bonded in a rectangular see-saw-like geometry to one In(2), two equivalent In(1), and one Sn(1) atom. In the sixth S site, S(6) is bonded in a 3-coordinate geometry to three equivalent In(1) atoms. In the seventh S site, S(7) is bonded to two equivalent Sn(3) and three equivalent Sn(2) atoms to form distorted SSn5 trigonal bipyramids that share corners with four equivalent S(2)In3Sn2 square pyramids,  an edgeedge with one S(2)In3Sn2 square pyramid, and edges with four equivalent S(7)Sn5 trigonal bipyramids.
In2Sn3S7 crystallizes in the monoclinic P2_1/m space group. There are two inequivalent In sites. In the first In site, In(1) is bonded to one S(4), two equivalent S(5), and three equivalent S(6) atoms to form InS6 octahedra that share corners with two equivalent Sn(1)S6 octahedra,  a cornercorner with one Sn(2)S6 pentagonal pyramid, edges with two equivalent In(2)S6 octahedra, and edges with four equivalent In(1)S6 octahedra. The corner-sharing octahedral tilt angles are 58°. The In(1)-S(4) bond length is 2.69 Å. Both In(1)-S(5) bond lengths are 2.67 Å. There is one shorter (2.58 Å) and two longer (2.63 Å) In(1)-S(6) bond lengths. In the second In site, In(2) is bonded to one S(5), two equivalent S(4), and three equivalent S(2) atoms to form InS6 octahedra that share  a cornercorner with one Sn(1)S6 octahedra, corners with two equivalent Sn(2)S6 pentagonal pyramids, edges with two equivalent In(1)S6 octahedra, edges with four equivalent In(2)S6 octahedra, and edges with three equivalent Sn(2)S6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 54°. The In(2)-S(5) bond length is 2.73 Å. Both In(2)-S(4) bond lengths are 2.63 Å. There is one shorter (2.60 Å) and two longer (2.66 Å) In(2)-S(2) bond lengths. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one S(5), two equivalent S(3), and three equivalent S(1) atoms to form SnS6 octahedra that share  a cornercorner with one In(2)S6 octahedra, corners with two equivalent In(1)S6 octahedra, and edges with four equivalent Sn(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 54-58°. The Sn(1)-S(5) bond length is 2.59 Å. Both Sn(1)-S(3) bond lengths are 2.58 Å. There is one shorter (2.57 Å) and two longer (2.68 Å) Sn(1)-S(1) bond lengths. In the second Sn site, Sn(2) is bonded to one S(4), two equivalent S(2), and three equivalent S(7) atoms to form distorted SnS6 pentagonal pyramids that share  a cornercorner with one In(1)S6 octahedra, corners with two equivalent In(2)S6 octahedra, edges with three equivalent In(2)S6 octahedra, and edges with four equivalent Sn(2)S6 pentagonal pyramids. The corner-sharing octahedral tilt angles range from 10-19°. The Sn(2)-S(4) bond length is 2.98 Å. Both Sn(2)-S(2) bond lengths are 3.10 Å. There are two shorter (2.82 Å) and one longer (3.06 Å) Sn(2)-S(7) bond length. In the third Sn site, Sn(3) is bonded in a 3-coordinate geometry to one S(3), one S(4), and two equivalent S(7) atoms. The Sn(3)-S(3) bond length is 2.91 Å. The Sn(3)-S(4) bond length is 3.14 Å. Both Sn(3)-S(7) bond lengths are 2.82 Å. There are seven inequivalent S sites. In the first S site, S(1) is bonded in a distorted T-shaped geometry to three equivalent Sn(1) atoms. In the second S site, S(2) is bonded to three equivalent In(2) and two equivalent Sn(2) atoms to form distorted SIn3Sn2 square pyramids that share corners with four equivalent S(7)Sn5 trigonal bipyramids, edges with four equivalent S(2)In3Sn2 square pyramids, and  an edgeedge with one S(7)Sn5 trigonal bipyramid. In the third S site, S(3) is bonded in a trigonal non-coplanar geometry to one Sn(3) and two equivalent Sn(1) atoms. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to one In(1), two equivalent In(2), one Sn(2), and one Sn(3) atom. In the fifth S site, S(5) is bonded in a rectangular see-saw-like geometry to one In(2), two equivalent In(1), and one Sn(1) atom. In the sixth S site, S(6) is bonded in a 3-coordinate geometry to three equivalent In(1) atoms. In the seventh S site, S(7) is bonded to two equivalent Sn(3) and three equivalent Sn(2) atoms to form distorted SSn5 trigonal bipyramids that share corners with four equivalent S(2)In3Sn2 square pyramids,  an edgeedge with one S(2)In3Sn2 square pyramid, and edges with four equivalent S(7)Sn5 trigonal bipyramids.