Ca3SnS5 crystallizes in the trigonal R3m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one S(2), one S(6), two equivalent S(7), and two equivalent S(9) atoms. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one S(1), one S(3), one S(4), one S(5), and two equivalent S(8) atoms. In the third Ca site, Ca(3) is bonded in a distorted hexagonal planar geometry to one S(2), one S(3), one S(8), one S(9), and two equivalent S(7) atoms. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a tetrahedral geometry to one S(4) and three equivalent S(9) atoms. In the second Sn site, Sn(2) is bonded in a tetrahedral geometry to one S(6) and three equivalent S(8) atoms. In the third Sn site, Sn(3) is bonded to one S(1) and three equivalent S(7) atoms to form SnS4 tetrahedra that share  a cornercorner with one S(4)Ca3SnS tetrahedra. There are nine inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to three equivalent Ca(2), one Sn(3), and one S(4) atom. In the second S site, S(2) is bonded in a 6-coordinate geometry to three equivalent Ca(1) and three equivalent Ca(3) atoms. In the third S site, S(3) is bonded to three equivalent Ca(2) and three equivalent Ca(3) atoms to form distorted SCa6 octahedra that share corners with three equivalent S(4)Ca3SnS tetrahedra, corners with three equivalent S(9)Ca3Sn trigonal pyramids, edges with three equivalent S(7)Ca4Sn trigonal bipyramids, and faces with three equivalent S(8)Ca3Sn tetrahedra. In the fourth S site, S(4) is bonded to three equivalent Ca(2), one Sn(1), and one S(1) atom to form distorted SCa3SnS tetrahedra that share corners with three equivalent S(3)Ca6 octahedra,  a cornercorner with one Sn(3)S4 tetrahedra, corners with six equivalent S(8)Ca3Sn tetrahedra, and corners with three equivalent S(9)Ca3Sn trigonal pyramids. The corner-sharing octahedral tilt angles are 24°. In the fifth S site, S(5) is bonded in a 3-coordinate geometry to three equivalent Ca(2) atoms. In the sixth S site, S(6) is bonded to three equivalent Ca(1) and one Sn(2) atom to form distorted SCa3Sn trigonal pyramids that share corners with three equivalent S(8)Ca3Sn tetrahedra, corners with six equivalent S(9)Ca3Sn trigonal pyramids, and edges with three equivalent S(7)Ca4Sn trigonal bipyramids. In the seventh S site, S(7) is bonded to two equivalent Ca(1), two equivalent Ca(3), and one Sn(3) atom to form distorted SCa4Sn trigonal bipyramids that share corners with two equivalent S(8)Ca3Sn tetrahedra, corners with two equivalent S(7)Ca4Sn trigonal bipyramids, corners with two equivalent S(9)Ca3Sn trigonal pyramids,  an edgeedge with one S(3)Ca6 octahedra, edges with two equivalent S(7)Ca4Sn trigonal bipyramids,  an edgeedge with one S(6)Ca3Sn trigonal pyramid, and edges with two equivalent S(9)Ca3Sn trigonal pyramids. In the eighth S site, S(8) is bonded to one Ca(3), two equivalent Ca(2), and one Sn(2) atom to form distorted SCa3Sn tetrahedra that share corners with two equivalent S(4)Ca3SnS tetrahedra, corners with four equivalent S(8)Ca3Sn tetrahedra, corners with two equivalent S(7)Ca4Sn trigonal bipyramids,  a cornercorner with one S(6)Ca3Sn trigonal pyramid,  a cornercorner with one S(9)Ca3Sn trigonal pyramid, and  a faceface with one S(3)Ca6 octahedra. In the ninth S site, S(9) is bonded to one Ca(3), two equivalent Ca(1), and one Sn(1) atom to form SCa3Sn trigonal pyramids that share  a cornercorner with one S(3)Ca6 octahedra,  a cornercorner with one S(8)Ca3Sn tetrahedra,  a cornercorner with one S(4)Ca3SnS tetrahedra, corners with two equivalent S(7)Ca4Sn trigonal bipyramids, corners with two equivalent S(6)Ca3Sn trigonal pyramids, corners with four equivalent S(9)Ca3Sn trigonal pyramids, and edges with two equivalent S(7)Ca4Sn trigonal bipyramids. The corner-sharing octahedral tilt angles are 61°.
Ca3SnS5 crystallizes in the trigonal R3m space group. There are three inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 6-coordinate geometry to one S(2), one S(6), two equivalent S(7), and two equivalent S(9) atoms. The Ca(1)-S(2) bond length is 3.36 Å. The Ca(1)-S(6) bond length is 2.96 Å. Both Ca(1)-S(7) bond lengths are 3.04 Å. Both Ca(1)-S(9) bond lengths are 2.71 Å. In the second Ca site, Ca(2) is bonded in a 6-coordinate geometry to one S(1), one S(3), one S(4), one S(5), and two equivalent S(8) atoms. The Ca(2)-S(1) bond length is 3.20 Å. The Ca(2)-S(3) bond length is 3.26 Å. The Ca(2)-S(4) bond length is 3.08 Å. The Ca(2)-S(5) bond length is 2.82 Å. Both Ca(2)-S(8) bond lengths are 2.79 Å. In the third Ca site, Ca(3) is bonded in a distorted hexagonal planar geometry to one S(2), one S(3), one S(8), one S(9), and two equivalent S(7) atoms. The Ca(3)-S(2) bond length is 2.84 Å. The Ca(3)-S(3) bond length is 2.81 Å. The Ca(3)-S(8) bond length is 2.98 Å. The Ca(3)-S(9) bond length is 2.98 Å. Both Ca(3)-S(7) bond lengths are 2.93 Å. There are three inequivalent Sn sites. In the first Sn site, Sn(1) is bonded in a tetrahedral geometry to one S(4) and three equivalent S(9) atoms. The Sn(1)-S(4) bond length is 2.36 Å. All Sn(1)-S(9) bond lengths are 2.39 Å. In the second Sn site, Sn(2) is bonded in a tetrahedral geometry to one S(6) and three equivalent S(8) atoms. The Sn(2)-S(6) bond length is 2.49 Å. All Sn(2)-S(8) bond lengths are 2.41 Å. In the third Sn site, Sn(3) is bonded to one S(1) and three equivalent S(7) atoms to form SnS4 tetrahedra that share  a cornercorner with one S(4)Ca3SnS tetrahedra. The Sn(3)-S(1) bond length is 2.32 Å. All Sn(3)-S(7) bond lengths are 2.40 Å. There are nine inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to three equivalent Ca(2), one Sn(3), and one S(4) atom. The S(1)-S(4) bond length is 2.65 Å. In the second S site, S(2) is bonded in a 6-coordinate geometry to three equivalent Ca(1) and three equivalent Ca(3) atoms. In the third S site, S(3) is bonded to three equivalent Ca(2) and three equivalent Ca(3) atoms to form distorted SCa6 octahedra that share corners with three equivalent S(4)Ca3SnS tetrahedra, corners with three equivalent S(9)Ca3Sn trigonal pyramids, edges with three equivalent S(7)Ca4Sn trigonal bipyramids, and faces with three equivalent S(8)Ca3Sn tetrahedra. In the fourth S site, S(4) is bonded to three equivalent Ca(2), one Sn(1), and one S(1) atom to form distorted SCa3SnS tetrahedra that share corners with three equivalent S(3)Ca6 octahedra,  a cornercorner with one Sn(3)S4 tetrahedra, corners with six equivalent S(8)Ca3Sn tetrahedra, and corners with three equivalent S(9)Ca3Sn trigonal pyramids. The corner-sharing octahedral tilt angles are 24°. In the fifth S site, S(5) is bonded in a 3-coordinate geometry to three equivalent Ca(2) atoms. In the sixth S site, S(6) is bonded to three equivalent Ca(1) and one Sn(2) atom to form distorted SCa3Sn trigonal pyramids that share corners with three equivalent S(8)Ca3Sn tetrahedra, corners with six equivalent S(9)Ca3Sn trigonal pyramids, and edges with three equivalent S(7)Ca4Sn trigonal bipyramids. In the seventh S site, S(7) is bonded to two equivalent Ca(1), two equivalent Ca(3), and one Sn(3) atom to form distorted SCa4Sn trigonal bipyramids that share corners with two equivalent S(8)Ca3Sn tetrahedra, corners with two equivalent S(7)Ca4Sn trigonal bipyramids, corners with two equivalent S(9)Ca3Sn trigonal pyramids,  an edgeedge with one S(3)Ca6 octahedra, edges with two equivalent S(7)Ca4Sn trigonal bipyramids,  an edgeedge with one S(6)Ca3Sn trigonal pyramid, and edges with two equivalent S(9)Ca3Sn trigonal pyramids. In the eighth S site, S(8) is bonded to one Ca(3), two equivalent Ca(2), and one Sn(2) atom to form distorted SCa3Sn tetrahedra that share corners with two equivalent S(4)Ca3SnS tetrahedra, corners with four equivalent S(8)Ca3Sn tetrahedra, corners with two equivalent S(7)Ca4Sn trigonal bipyramids,  a cornercorner with one S(6)Ca3Sn trigonal pyramid,  a cornercorner with one S(9)Ca3Sn trigonal pyramid, and  a faceface with one S(3)Ca6 octahedra. In the ninth S site, S(9) is bonded to one Ca(3), two equivalent Ca(1), and one Sn(1) atom to form SCa3Sn trigonal pyramids that share  a cornercorner with one S(3)Ca6 octahedra,  a cornercorner with one S(8)Ca3Sn tetrahedra,  a cornercorner with one S(4)Ca3SnS tetrahedra, corners with two equivalent S(7)Ca4Sn trigonal bipyramids, corners with two equivalent S(6)Ca3Sn trigonal pyramids, corners with four equivalent S(9)Ca3Sn trigonal pyramids, and edges with two equivalent S(7)Ca4Sn trigonal bipyramids. The corner-sharing octahedral tilt angles are 61°.