Na4Sn3S8 crystallizes in the monoclinic C2/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one S(1), two equivalent S(3), and two equivalent S(4) atoms. In the second Na site, Na(2) is bonded to one S(1), one S(2), one S(3), and two equivalent S(4) atoms to form NaS5 trigonal bipyramids that share corners with three equivalent Sn(2)S4 tetrahedra, corners with two equivalent Na(2)S5 trigonal bipyramids, corners with three equivalent Sn(1)S5 trigonal bipyramids, and  an edgeedge with one Sn(1)S5 trigonal bipyramid. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one S(2), two equivalent S(1), and two equivalent S(3) atoms to form SnS5 trigonal bipyramids that share  a cornercorner with one Sn(2)S4 tetrahedra, corners with three equivalent Na(2)S5 trigonal bipyramids,  an edgeedge with one Na(2)S5 trigonal bipyramid, and edges with two equivalent Sn(1)S5 trigonal bipyramids. In the second Sn site, Sn(2) is bonded to two equivalent S(2) and two equivalent S(4) atoms to form SnS4 tetrahedra that share corners with two equivalent Sn(1)S5 trigonal bipyramids and corners with six equivalent Na(2)S5 trigonal bipyramids. There are four inequivalent S sites. In the first S site, S(3) is bonded to one Na(2), two equivalent Na(1), and two equivalent Sn(1) atoms to form distorted SNa3Sn2 square pyramids that share corners with four equivalent S(4)Na4Sn trigonal bipyramids, edges with two equivalent S(3)Na3Sn2 square pyramids, and  an edgeedge with one S(4)Na4Sn trigonal bipyramid. In the second S site, S(4) is bonded to two equivalent Na(1), two equivalent Na(2), and one Sn(2) atom to form distorted SNa4Sn trigonal bipyramids that share corners with four equivalent S(3)Na3Sn2 square pyramids,  a cornercorner with one S(4)Na4Sn trigonal bipyramid,  an edgeedge with one S(3)Na3Sn2 square pyramid, and edges with two equivalent S(4)Na4Sn trigonal bipyramids. In the third S site, S(1) is bonded in a distorted see-saw-like geometry to one Na(1), one Na(2), and two equivalent Sn(1) atoms. In the fourth S site, S(2) is bonded in a distorted trigonal planar geometry to one Na(2), one Sn(1), and one Sn(2) atom.
Na4Sn3S8 crystallizes in the monoclinic C2/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to one S(1), two equivalent S(3), and two equivalent S(4) atoms. The Na(1)-S(1) bond length is 3.00 Å. There is one shorter (2.93 Å) and one longer (3.34 Å) Na(1)-S(3) bond length. There is one shorter (2.93 Å) and one longer (3.03 Å) Na(1)-S(4) bond length. In the second Na site, Na(2) is bonded to one S(1), one S(2), one S(3), and two equivalent S(4) atoms to form NaS5 trigonal bipyramids that share corners with three equivalent Sn(2)S4 tetrahedra, corners with two equivalent Na(2)S5 trigonal bipyramids, corners with three equivalent Sn(1)S5 trigonal bipyramids, and  an edgeedge with one Sn(1)S5 trigonal bipyramid. The Na(2)-S(1) bond length is 2.83 Å. The Na(2)-S(2) bond length is 2.87 Å. The Na(2)-S(3) bond length is 2.86 Å. There is one shorter (2.75 Å) and one longer (2.79 Å) Na(2)-S(4) bond length. There are two inequivalent Sn sites. In the first Sn site, Sn(1) is bonded to one S(2), two equivalent S(1), and two equivalent S(3) atoms to form SnS5 trigonal bipyramids that share  a cornercorner with one Sn(2)S4 tetrahedra, corners with three equivalent Na(2)S5 trigonal bipyramids,  an edgeedge with one Na(2)S5 trigonal bipyramid, and edges with two equivalent Sn(1)S5 trigonal bipyramids. The Sn(1)-S(2) bond length is 2.47 Å. There is one shorter (2.41 Å) and one longer (2.60 Å) Sn(1)-S(1) bond length. There is one shorter (2.43 Å) and one longer (2.61 Å) Sn(1)-S(3) bond length. In the second Sn site, Sn(2) is bonded to two equivalent S(2) and two equivalent S(4) atoms to form SnS4 tetrahedra that share corners with two equivalent Sn(1)S5 trigonal bipyramids and corners with six equivalent Na(2)S5 trigonal bipyramids. Both Sn(2)-S(2) bond lengths are 2.47 Å. Both Sn(2)-S(4) bond lengths are 2.36 Å. There are four inequivalent S sites. In the first S site, S(3) is bonded to one Na(2), two equivalent Na(1), and two equivalent Sn(1) atoms to form distorted SNa3Sn2 square pyramids that share corners with four equivalent S(4)Na4Sn trigonal bipyramids, edges with two equivalent S(3)Na3Sn2 square pyramids, and  an edgeedge with one S(4)Na4Sn trigonal bipyramid. In the second S site, S(4) is bonded to two equivalent Na(1), two equivalent Na(2), and one Sn(2) atom to form distorted SNa4Sn trigonal bipyramids that share corners with four equivalent S(3)Na3Sn2 square pyramids,  a cornercorner with one S(4)Na4Sn trigonal bipyramid,  an edgeedge with one S(3)Na3Sn2 square pyramid, and edges with two equivalent S(4)Na4Sn trigonal bipyramids. In the third S site, S(1) is bonded in a distorted see-saw-like geometry to one Na(1), one Na(2), and two equivalent Sn(1) atoms. In the fourth S site, S(2) is bonded in a distorted trigonal planar geometry to one Na(2), one Sn(1), and one Sn(2) atom.