Ca3Sn2S7 crystallizes in the orthorhombic Pmmm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to four equivalent S(7) and four equivalent S(8) atoms. In the second Ca site, Ca(2) is bonded in a distorted body-centered cubic geometry to four equivalent S(5) and four equivalent S(6) atoms. In the third Ca site, Ca(3) is bonded in a 5-coordinate geometry to one S(3), two equivalent S(7), and two equivalent S(8) atoms. In the fourth Ca site, Ca(4) is bonded in a 5-coordinate geometry to one S(4), two equivalent S(5), 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(3), two equivalent S(5), and two equivalent S(6) atoms to form distorted corner-sharing SnS6 octahedra. The corner-sharing octahedral tilt angles range from 0-25°. In the second Sn site, Sn(2) is bonded to one S(2), one S(4), two equivalent S(7), and two equivalent S(8) atoms to form distorted corner-sharing SnS6 octahedra. The corner-sharing octahedral tilt angles range from 0-26°. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a linear geometry to two equivalent Sn(1) atoms. In the second S site, S(2) is bonded in a linear geometry to two equivalent Sn(2) atoms. In the third S site, S(3) is bonded in a linear geometry to one Ca(3) and one Sn(1) atom. In the fourth S site, S(4) is bonded in a linear geometry to one Ca(4) and one Sn(2) atom. In the fifth S site, S(5) is bonded to two equivalent Ca(2), two equivalent Ca(4), and two equivalent Sn(1) atoms to form a mixture of distorted corner, face, and edge-sharing SCa4Sn2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the sixth S site, S(6) is bonded to two equivalent Ca(2), two equivalent Ca(4), and two equivalent Sn(1) atoms to form a mixture of distorted corner, face, and edge-sharing SCa4Sn2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the seventh S site, S(7) is bonded to two equivalent Ca(1), two equivalent Ca(3), and two equivalent Sn(2) atoms to form a mixture of distorted corner, face, and edge-sharing SCa4Sn2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°. In the eighth S site, S(8) is bonded to two equivalent Ca(1), two equivalent Ca(3), and two equivalent Sn(2) atoms to form a mixture of distorted corner, face, and edge-sharing SCa4Sn2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°.
Ca3Sn2S7 crystallizes in the orthorhombic Pmmm space group. There are four inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to four equivalent S(7) and four equivalent S(8) atoms. All Ca(1)-S(7) bond lengths are 3.39 Å. All Ca(1)-S(8) bond lengths are 3.27 Å. In the second Ca site, Ca(2) is bonded in a distorted body-centered cubic geometry to four equivalent S(5) and four equivalent S(6) atoms. All Ca(2)-S(5) bond lengths are 3.24 Å. All Ca(2)-S(6) bond lengths are 3.26 Å. In the third Ca site, Ca(3) is bonded in a 5-coordinate geometry to one S(3), two equivalent S(7), and two equivalent S(8) atoms. The Ca(3)-S(3) bond length is 2.69 Å. Both Ca(3)-S(7) bond lengths are 3.04 Å. Both Ca(3)-S(8) bond lengths are 3.20 Å. In the fourth Ca site, Ca(4) is bonded in a 5-coordinate geometry to one S(4), two equivalent S(5), and two equivalent S(6) atoms. The Ca(4)-S(4) bond length is 2.69 Å. Both Ca(4)-S(5) bond lengths are 3.13 Å. Both Ca(4)-S(6) bond lengths are 3.17 Å. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one S(1), one S(3), two equivalent S(5), and two equivalent S(6) atoms to form distorted corner-sharing SnS6 octahedra. The corner-sharing octahedral tilt angles range from 0-25°. The Sn(1)-S(1) bond length is 2.60 Å. The Sn(1)-S(3) bond length is 2.39 Å. Both Sn(1)-S(5) bond lengths are 2.57 Å. Both Sn(1)-S(6) bond lengths are 2.54 Å. In the second Sn site, Sn(2) is bonded to one S(2), one S(4), two equivalent S(7), and two equivalent S(8) atoms to form distorted corner-sharing SnS6 octahedra. The corner-sharing octahedral tilt angles range from 0-26°. The Sn(2)-S(2) bond length is 2.65 Å. The Sn(2)-S(4) bond length is 2.41 Å. Both Sn(2)-S(7) bond lengths are 2.54 Å. Both Sn(2)-S(8) bond lengths are 2.55 Å. There are eight inequivalent S sites. In the first S site, S(1) is bonded in a linear geometry to two equivalent Sn(1) atoms. In the second S site, S(2) is bonded in a linear geometry to two equivalent Sn(2) atoms. In the third S site, S(3) is bonded in a linear geometry to one Ca(3) and one Sn(1) atom. In the fourth S site, S(4) is bonded in a linear geometry to one Ca(4) and one Sn(2) atom. In the fifth S site, S(5) is bonded to two equivalent Ca(2), two equivalent Ca(4), and two equivalent Sn(1) atoms to form a mixture of distorted corner, face, and edge-sharing SCa4Sn2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the sixth S site, S(6) is bonded to two equivalent Ca(2), two equivalent Ca(4), and two equivalent Sn(1) atoms to form a mixture of distorted corner, face, and edge-sharing SCa4Sn2 octahedra. The corner-sharing octahedral tilt angles range from 0-66°. In the seventh S site, S(7) is bonded to two equivalent Ca(1), two equivalent Ca(3), and two equivalent Sn(2) atoms to form a mixture of distorted corner, face, and edge-sharing SCa4Sn2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°. In the eighth S site, S(8) is bonded to two equivalent Ca(1), two equivalent Ca(3), and two equivalent Sn(2) atoms to form a mixture of distorted corner, face, and edge-sharing SCa4Sn2 octahedra. The corner-sharing octahedral tilt angles range from 0-64°.