Ca4SnS6 crystallizes in the monoclinic Cc space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one S(1), one S(2), one S(3), one S(5), and one S(6) atom to form distorted CaS5 trigonal bipyramids that share  a cornercorner with one Sn(1)S4 tetrahedra, corners with three equivalent Ca(3)S4 tetrahedra, corners with four equivalent Ca(4)S5 trigonal bipyramids, corners with four equivalent Ca(2)S4 trigonal pyramids, and  an edgeedge with one Sn(1)S4 tetrahedra. In the second Ca site, Ca(2) is bonded to one S(1), one S(2), one S(3), and one S(5) atom to form CaS4 trigonal pyramids that share corners with two equivalent Ca(3)S4 tetrahedra, corners with two equivalent Sn(1)S4 tetrahedra, corners with three equivalent Ca(4)S5 trigonal bipyramids, and corners with four equivalent Ca(1)S5 trigonal bipyramids. In the third Ca site, Ca(3) is bonded to one S(1), one S(4), one S(5), and one S(6) atom to form CaS4 tetrahedra that share corners with two equivalent Sn(1)S4 tetrahedra, corners with three equivalent Ca(1)S5 trigonal bipyramids, corners with four equivalent Ca(4)S5 trigonal bipyramids, and corners with two equivalent Ca(2)S4 trigonal pyramids. In the fourth Ca site, Ca(4) is bonded to one S(1), one S(2), one S(4), one S(5), and one S(6) atom to form distorted CaS5 trigonal bipyramids that share  a cornercorner with one Sn(1)S4 tetrahedra, corners with four equivalent Ca(3)S4 tetrahedra, corners with four equivalent Ca(1)S5 trigonal bipyramids, corners with three equivalent Ca(2)S4 trigonal pyramids, and  an edgeedge with one Sn(1)S4 tetrahedra. Sn(1) is bonded to one S(2), one S(3), one S(4), and one S(6) atom to form SnS4 tetrahedra that share corners with two equivalent Ca(3)S4 tetrahedra,  a cornercorner with one Ca(1)S5 trigonal bipyramid,  a cornercorner with one Ca(4)S5 trigonal bipyramid, corners with two equivalent Ca(2)S4 trigonal pyramids,  an edgeedge with one Ca(1)S5 trigonal bipyramid, and  an edgeedge with one Ca(4)S5 trigonal bipyramid. There are six inequivalent S sites. In the first S site, S(1) is bonded to one Ca(1), one Ca(2), one Ca(3), and one Ca(4) atom to form SCa4 tetrahedra that share corners with four equivalent S(5)Ca4 tetrahedra, corners with three equivalent S(2)Ca3Sn trigonal pyramids, and corners with three equivalent S(6)Ca3Sn trigonal pyramids. In the second S site, S(2) is bonded to one Ca(1), one Ca(2), one Ca(4), and one Sn(1) atom to form SCa3Sn trigonal pyramids that share corners with three equivalent S(1)Ca4 tetrahedra, corners with three equivalent S(5)Ca4 tetrahedra,  a cornercorner with one S(6)Ca3Sn trigonal pyramid, and  an edgeedge with one S(6)Ca3Sn trigonal pyramid. In the third S site, S(3) is bonded in a trigonal non-coplanar geometry to one Ca(1), one Ca(2), and one Sn(1) atom. In the fourth S site, S(4) is bonded in a trigonal non-coplanar geometry to one Ca(3), one Ca(4), and one Sn(1) atom. In the fifth S site, S(5) is bonded to one Ca(1), one Ca(2), one Ca(3), and one Ca(4) atom to form SCa4 tetrahedra that share corners with four equivalent S(1)Ca4 tetrahedra, corners with three equivalent S(2)Ca3Sn trigonal pyramids, and corners with three equivalent S(6)Ca3Sn trigonal pyramids. In the sixth S site, S(6) is bonded to one Ca(1), one Ca(3), one Ca(4), and one Sn(1) atom to form SCa3Sn trigonal pyramids that share corners with three equivalent S(1)Ca4 tetrahedra, corners with three equivalent S(5)Ca4 tetrahedra,  a cornercorner with one S(2)Ca3Sn trigonal pyramid, and  an edgeedge with one S(2)Ca3Sn trigonal pyramid.
Ca4SnS6 crystallizes in the monoclinic Cc space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one S(1), one S(2), one S(3), one S(5), and one S(6) atom to form distorted CaS5 trigonal bipyramids that share  a cornercorner with one Sn(1)S4 tetrahedra, corners with three equivalent Ca(3)S4 tetrahedra, corners with four equivalent Ca(4)S5 trigonal bipyramids, corners with four equivalent Ca(2)S4 trigonal pyramids, and  an edgeedge with one Sn(1)S4 tetrahedra. The Ca(1)-S(1) bond length is 2.71 Å. The Ca(1)-S(2) bond length is 3.14 Å. The Ca(1)-S(3) bond length is 2.81 Å. The Ca(1)-S(5) bond length is 2.76 Å. The Ca(1)-S(6) bond length is 2.91 Å. In the second Ca site, Ca(2) is bonded to one S(1), one S(2), one S(3), and one S(5) atom to form CaS4 trigonal pyramids that share corners with two equivalent Ca(3)S4 tetrahedra, corners with two equivalent Sn(1)S4 tetrahedra, corners with three equivalent Ca(4)S5 trigonal bipyramids, and corners with four equivalent Ca(1)S5 trigonal bipyramids. The Ca(2)-S(1) bond length is 2.70 Å. The Ca(2)-S(2) bond length is 2.81 Å. The Ca(2)-S(3) bond length is 2.77 Å. The Ca(2)-S(5) bond length is 2.73 Å. In the third Ca site, Ca(3) is bonded to one S(1), one S(4), one S(5), and one S(6) atom to form CaS4 tetrahedra that share corners with two equivalent Sn(1)S4 tetrahedra, corners with three equivalent Ca(1)S5 trigonal bipyramids, corners with four equivalent Ca(4)S5 trigonal bipyramids, and corners with two equivalent Ca(2)S4 trigonal pyramids. The Ca(3)-S(1) bond length is 2.71 Å. The Ca(3)-S(4) bond length is 2.83 Å. The Ca(3)-S(5) bond length is 2.74 Å. The Ca(3)-S(6) bond length is 2.81 Å. In the fourth Ca site, Ca(4) is bonded to one S(1), one S(2), one S(4), one S(5), and one S(6) atom to form distorted CaS5 trigonal bipyramids that share  a cornercorner with one Sn(1)S4 tetrahedra, corners with four equivalent Ca(3)S4 tetrahedra, corners with four equivalent Ca(1)S5 trigonal bipyramids, corners with three equivalent Ca(2)S4 trigonal pyramids, and  an edgeedge with one Sn(1)S4 tetrahedra. The Ca(4)-S(1) bond length is 2.71 Å. The Ca(4)-S(2) bond length is 2.83 Å. The Ca(4)-S(4) bond length is 2.94 Å. The Ca(4)-S(5) bond length is 2.76 Å. The Ca(4)-S(6) bond length is 3.10 Å. Sn(1) is bonded to one S(2), one S(3), one S(4), and one S(6) atom to form SnS4 tetrahedra that share corners with two equivalent Ca(3)S4 tetrahedra,  a cornercorner with one Ca(1)S5 trigonal bipyramid,  a cornercorner with one Ca(4)S5 trigonal bipyramid, corners with two equivalent Ca(2)S4 trigonal pyramids,  an edgeedge with one Ca(1)S5 trigonal bipyramid, and  an edgeedge with one Ca(4)S5 trigonal bipyramid. The Sn(1)-S(2) bond length is 2.43 Å. The Sn(1)-S(3) bond length is 2.39 Å. The Sn(1)-S(4) bond length is 2.39 Å. The Sn(1)-S(6) bond length is 2.41 Å. There are six inequivalent S sites. In the first S site, S(1) is bonded to one Ca(1), one Ca(2), one Ca(3), and one Ca(4) atom to form SCa4 tetrahedra that share corners with four equivalent S(5)Ca4 tetrahedra, corners with three equivalent S(2)Ca3Sn trigonal pyramids, and corners with three equivalent S(6)Ca3Sn trigonal pyramids. In the second S site, S(2) is bonded to one Ca(1), one Ca(2), one Ca(4), and one Sn(1) atom to form SCa3Sn trigonal pyramids that share corners with three equivalent S(1)Ca4 tetrahedra, corners with three equivalent S(5)Ca4 tetrahedra,  a cornercorner with one S(6)Ca3Sn trigonal pyramid, and  an edgeedge with one S(6)Ca3Sn trigonal pyramid. In the third S site, S(3) is bonded in a trigonal non-coplanar geometry to one Ca(1), one Ca(2), and one Sn(1) atom. In the fourth S site, S(4) is bonded in a trigonal non-coplanar geometry to one Ca(3), one Ca(4), and one Sn(1) atom. In the fifth S site, S(5) is bonded to one Ca(1), one Ca(2), one Ca(3), and one Ca(4) atom to form SCa4 tetrahedra that share corners with four equivalent S(1)Ca4 tetrahedra, corners with three equivalent S(2)Ca3Sn trigonal pyramids, and corners with three equivalent S(6)Ca3Sn trigonal pyramids. In the sixth S site, S(6) is bonded to one Ca(1), one Ca(3), one Ca(4), and one Sn(1) atom to form SCa3Sn trigonal pyramids that share corners with three equivalent S(1)Ca4 tetrahedra, corners with three equivalent S(5)Ca4 tetrahedra,  a cornercorner with one S(2)Ca3Sn trigonal pyramid, and  an edgeedge with one S(2)Ca3Sn trigonal pyramid.