Ca3Sn2S7 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 5-coordinate geometry to one S(1) and four equivalent S(4) atoms. In the second Ca site, Ca(2) is bonded in a 4-coordinate geometry to two equivalent S(2) and two equivalent S(3) atoms. Sn(1) is bonded to one S(1), one S(2), two equivalent S(3), and two equivalent S(4) atoms to form corner-sharing SnS6 octahedra. The corner-sharing octahedral tilt angles range from 32-38°. There are four inequivalent S sites. In the first S site, S(1) is bonded in a distorted trigonal planar geometry to one Ca(1) and two equivalent Sn(1) atoms. In the second S site, S(2) is bonded in a 3-coordinate geometry to two equivalent Ca(2) and one Sn(1) atom. In the third S site, S(3) is bonded to two equivalent Ca(2) and two equivalent Sn(1) atoms to form a mixture of distorted corner and edge-sharing SCa2Sn2 trigonal pyramids. In the fourth S site, S(4) is bonded to two equivalent Ca(1) and two equivalent Sn(1) atoms to form a mixture of distorted corner and edge-sharing SCa2Sn2 tetrahedra.
Ca3Sn2S7 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 5-coordinate geometry to one S(1) and four equivalent S(4) atoms. The Ca(1)-S(1) bond length is 2.90 Å. All Ca(1)-S(4) bond lengths are 2.87 Å. In the second Ca site, Ca(2) is bonded in a 4-coordinate geometry to two equivalent S(2) and two equivalent S(3) atoms. There is one shorter (2.71 Å) and one longer (2.74 Å) Ca(2)-S(2) bond length. Both Ca(2)-S(3) bond lengths are 2.85 Å. Sn(1) is bonded to one S(1), one S(2), two equivalent S(3), and two equivalent S(4) atoms to form corner-sharing SnS6 octahedra. The corner-sharing octahedral tilt angles range from 32-38°. The Sn(1)-S(1) bond length is 2.63 Å. The Sn(1)-S(2) bond length is 2.52 Å. Both Sn(1)-S(3) bond lengths are 2.56 Å. Both Sn(1)-S(4) bond lengths are 2.60 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a distorted trigonal planar geometry to one Ca(1) and two equivalent Sn(1) atoms. In the second S site, S(2) is bonded in a 3-coordinate geometry to two equivalent Ca(2) and one Sn(1) atom. In the third S site, S(3) is bonded to two equivalent Ca(2) and two equivalent Sn(1) atoms to form a mixture of distorted corner and edge-sharing SCa2Sn2 trigonal pyramids. In the fourth S site, S(4) is bonded to two equivalent Ca(1) and two equivalent Sn(1) atoms to form a mixture of distorted corner and edge-sharing SCa2Sn2 tetrahedra.