CaSnS3 crystallizes in the monoclinic Pm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one S(7), two equivalent S(1), two equivalent S(3), and two equivalent S(4) atoms. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one S(8), two equivalent S(1), two equivalent S(3), and two equivalent S(4) atoms. In the third Ca site, Ca(3) is bonded in a 5-coordinate geometry to one S(7), two equivalent S(2), and two equivalent S(5) atoms. In the fourth Ca site, Ca(4) is bonded in a 6-coordinate geometry to two equivalent S(2), two equivalent S(4), and two equivalent S(6) atoms. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one S(1), one S(2), one S(5), one S(8), and two equivalent S(3) atoms to form distorted corner-sharing SnS6 pentagonal pyramids. In the second Sn site, Sn(2) is bonded to one S(1), one S(2), one S(6), one S(7), and two equivalent S(4) atoms to form corner-sharing SnS6 pentagonal pyramids. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a distorted see-saw-like geometry to one Ca(1), one Ca(2), one Sn(1), and one Sn(2) atom. In the second S site, S(2) is bonded to one Ca(3), one Ca(4), one Sn(1), and one Sn(2) atom to form distorted SCa2Sn2 trigonal pyramids that share corners with two equivalent S(3)Ca2Sn2 tetrahedra, corners with two equivalent S(4)Ca3Sn2 trigonal bipyramids,  a cornercorner with one S(5)Ca2Sn2 trigonal pyramid, corners with two equivalent S(2)Ca2Sn2 trigonal pyramids,  an edgeedge with one S(4)Ca3Sn2 trigonal bipyramid, and  an edgeedge with one S(5)Ca2Sn2 trigonal pyramid. In the third S site, S(3) is bonded to one Ca(1), one Ca(2), and two equivalent Sn(1) atoms to form distorted SCa2Sn2 tetrahedra that share corners with four equivalent S(3)Ca2Sn2 tetrahedra, corners with two equivalent S(4)Ca3Sn2 trigonal bipyramids, corners with two equivalent S(2)Ca2Sn2 trigonal pyramids, corners with two equivalent S(5)Ca2Sn2 trigonal pyramids, and  an edgeedge with one S(4)Ca3Sn2 trigonal bipyramid. In the fourth S site, S(4) is bonded to one Ca(1), one Ca(2), one Ca(4), and two equivalent Sn(2) atoms to form distorted SCa3Sn2 trigonal bipyramids that share corners with two equivalent S(3)Ca2Sn2 tetrahedra, corners with three equivalent S(4)Ca3Sn2 trigonal bipyramids, corners with two equivalent S(2)Ca2Sn2 trigonal pyramids,  an edgeedge with one S(3)Ca2Sn2 tetrahedra,  an edgeedge with one S(4)Ca3Sn2 trigonal bipyramid, and  an edgeedge with one S(2)Ca2Sn2 trigonal pyramid. In the fifth S site, S(5) is bonded to two equivalent Ca(3) and two equivalent Sn(1) atoms to form a mixture of distorted corner and edge-sharing SCa2Sn2 trigonal pyramids. In the sixth S site, S(6) is bonded in a see-saw-like geometry to two equivalent Ca(4) and two equivalent Sn(2) atoms. In the seventh S site, S(7) is bonded in a distorted see-saw-like geometry to one Ca(1), one Ca(3), and two equivalent Sn(2) atoms. In the eighth S site, S(8) is bonded in a T-shaped geometry to one Ca(2) and two equivalent Sn(1) atoms.
CaSnS3 crystallizes in the monoclinic Pm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 7-coordinate geometry to one S(7), two equivalent S(1), two equivalent S(3), and two equivalent S(4) atoms. The Ca(1)-S(7) bond length is 2.91 Å. Both Ca(1)-S(1) bond lengths are 2.92 Å. Both Ca(1)-S(3) bond lengths are 3.11 Å. Both Ca(1)-S(4) bond lengths are 3.23 Å. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one S(8), two equivalent S(1), two equivalent S(3), and two equivalent S(4) atoms. The Ca(2)-S(8) bond length is 2.78 Å. Both Ca(2)-S(1) bond lengths are 3.16 Å. Both Ca(2)-S(3) bond lengths are 3.18 Å. Both Ca(2)-S(4) bond lengths are 3.17 Å. In the third Ca site, Ca(3) is bonded in a 5-coordinate geometry to one S(7), two equivalent S(2), and two equivalent S(5) atoms. The Ca(3)-S(7) bond length is 2.95 Å. Both Ca(3)-S(2) bond lengths are 2.84 Å. There is one shorter (2.73 Å) and one longer (2.96 Å) Ca(3)-S(5) bond length. In the fourth Ca site, Ca(4) is bonded in a 6-coordinate geometry to two equivalent S(2), two equivalent S(4), and two equivalent S(6) atoms. Both Ca(4)-S(2) bond lengths are 2.86 Å. Both Ca(4)-S(4) bond lengths are 3.21 Å. There is one shorter (2.74 Å) and one longer (2.96 Å) Ca(4)-S(6) bond length. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one S(1), one S(2), one S(5), one S(8), and two equivalent S(3) atoms to form distorted corner-sharing SnS6 pentagonal pyramids. The Sn(1)-S(1) bond length is 2.63 Å. The Sn(1)-S(2) bond length is 2.63 Å. The Sn(1)-S(5) bond length is 2.63 Å. The Sn(1)-S(8) bond length is 2.55 Å. There is one shorter (2.60 Å) and one longer (2.70 Å) Sn(1)-S(3) bond length. In the second Sn site, Sn(2) is bonded to one S(1), one S(2), one S(6), one S(7), and two equivalent S(4) atoms to form corner-sharing SnS6 pentagonal pyramids. The Sn(2)-S(1) bond length is 2.62 Å. The Sn(2)-S(2) bond length is 2.59 Å. The Sn(2)-S(6) bond length is 2.60 Å. The Sn(2)-S(7) bond length is 2.53 Å. There is one shorter (2.55 Å) and one longer (2.68 Å) Sn(2)-S(4) bond length. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a distorted see-saw-like geometry to one Ca(1), one Ca(2), one Sn(1), and one Sn(2) atom. In the second S site, S(2) is bonded to one Ca(3), one Ca(4), one Sn(1), and one Sn(2) atom to form distorted SCa2Sn2 trigonal pyramids that share corners with two equivalent S(3)Ca2Sn2 tetrahedra, corners with two equivalent S(4)Ca3Sn2 trigonal bipyramids,  a cornercorner with one S(5)Ca2Sn2 trigonal pyramid, corners with two equivalent S(2)Ca2Sn2 trigonal pyramids,  an edgeedge with one S(4)Ca3Sn2 trigonal bipyramid, and  an edgeedge with one S(5)Ca2Sn2 trigonal pyramid. In the third S site, S(3) is bonded to one Ca(1), one Ca(2), and two equivalent Sn(1) atoms to form distorted SCa2Sn2 tetrahedra that share corners with four equivalent S(3)Ca2Sn2 tetrahedra, corners with two equivalent S(4)Ca3Sn2 trigonal bipyramids, corners with two equivalent S(2)Ca2Sn2 trigonal pyramids, corners with two equivalent S(5)Ca2Sn2 trigonal pyramids, and  an edgeedge with one S(4)Ca3Sn2 trigonal bipyramid. In the fourth S site, S(4) is bonded to one Ca(1), one Ca(2), one Ca(4), and two equivalent Sn(2) atoms to form distorted SCa3Sn2 trigonal bipyramids that share corners with two equivalent S(3)Ca2Sn2 tetrahedra, corners with three equivalent S(4)Ca3Sn2 trigonal bipyramids, corners with two equivalent S(2)Ca2Sn2 trigonal pyramids,  an edgeedge with one S(3)Ca2Sn2 tetrahedra,  an edgeedge with one S(4)Ca3Sn2 trigonal bipyramid, and  an edgeedge with one S(2)Ca2Sn2 trigonal pyramid. In the fifth S site, S(5) is bonded to two equivalent Ca(3) and two equivalent Sn(1) atoms to form a mixture of distorted corner and edge-sharing SCa2Sn2 trigonal pyramids. In the sixth S site, S(6) is bonded in a see-saw-like geometry to two equivalent Ca(4) and two equivalent Sn(2) atoms. In the seventh S site, S(7) is bonded in a distorted see-saw-like geometry to one Ca(1), one Ca(3), and two equivalent Sn(2) atoms. In the eighth S site, S(8) is bonded in a T-shaped geometry to one Ca(2) and two equivalent Sn(1) atoms.