Y5S7 crystallizes in the monoclinic C2/m space group. There are three inequivalent Y sites. In the first Y site, Y(1) is bonded to one S(2), two equivalent S(4), and three equivalent S(1) atoms to form YS6 octahedra that share  a cornercorner with one Y(3)S6 octahedra, corners with two equivalent Y(1)S6 octahedra, corners with six equivalent Y(2)S7 pentagonal bipyramids, edges with five equivalent Y(1)S6 octahedra, and  an edgeedge with one Y(2)S7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 0-56°. In the second Y site, Y(2) is bonded to two equivalent S(1), two equivalent S(2), and three equivalent S(3) atoms to form distorted YS7 pentagonal bipyramids that share corners with two equivalent Y(3)S6 octahedra, corners with six equivalent Y(1)S6 octahedra,  an edgeedge with one Y(1)S6 octahedra, edges with three equivalent Y(3)S6 octahedra, edges with two equivalent Y(2)S7 pentagonal bipyramids, and faces with two equivalent Y(2)S7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 22-68°. In the third Y site, Y(3) is bonded to two equivalent S(2) and four equivalent S(3) atoms to form YS6 octahedra that share corners with two equivalent Y(1)S6 octahedra, corners with four equivalent Y(2)S7 pentagonal bipyramids, edges with two equivalent Y(3)S6 octahedra, and edges with six equivalent Y(2)S7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 56°. There are four inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Y(2) and three equivalent Y(1) atoms to form SY5 trigonal bipyramids that share corners with five equivalent S(2)Y4 tetrahedra, corners with four equivalent S(3)Y5 trigonal bipyramids,  an edgeedge with one S(2)Y4 tetrahedra,  an edgeedge with one S(3)Y5 trigonal bipyramid, and edges with four equivalent S(1)Y5 trigonal bipyramids. In the second S site, S(2) is bonded to one Y(1), one Y(3), and two equivalent Y(2) atoms to form distorted SY4 tetrahedra that share corners with three equivalent S(2)Y4 tetrahedra, corners with four equivalent S(3)Y5 trigonal bipyramids, corners with five equivalent S(1)Y5 trigonal bipyramids,  an edgeedge with one S(1)Y5 trigonal bipyramid, and edges with three equivalent S(3)Y5 trigonal bipyramids. In the third S site, S(3) is bonded to two equivalent Y(3) and three equivalent Y(2) atoms to form distorted SY5 trigonal bipyramids that share corners with four equivalent S(2)Y4 tetrahedra, corners with two equivalent S(3)Y5 trigonal bipyramids, corners with four equivalent S(1)Y5 trigonal bipyramids, edges with three equivalent S(2)Y4 tetrahedra,  an edgeedge with one S(1)Y5 trigonal bipyramid, and edges with five equivalent S(3)Y5 trigonal bipyramids. In the fourth S site, S(4) is bonded in a square co-planar geometry to four equivalent Y(1) atoms.
Y5S7 crystallizes in the monoclinic C2/m space group. There are three inequivalent Y sites. In the first Y site, Y(1) is bonded to one S(2), two equivalent S(4), and three equivalent S(1) atoms to form YS6 octahedra that share  a cornercorner with one Y(3)S6 octahedra, corners with two equivalent Y(1)S6 octahedra, corners with six equivalent Y(2)S7 pentagonal bipyramids, edges with five equivalent Y(1)S6 octahedra, and  an edgeedge with one Y(2)S7 pentagonal bipyramid. The corner-sharing octahedral tilt angles range from 0-56°. The Y(1)-S(2) bond length is 2.69 Å. Both Y(1)-S(4) bond lengths are 2.68 Å. There are two shorter (2.77 Å) and one longer (2.82 Å) Y(1)-S(1) bond length. In the second Y site, Y(2) is bonded to two equivalent S(1), two equivalent S(2), and three equivalent S(3) atoms to form distorted YS7 pentagonal bipyramids that share corners with two equivalent Y(3)S6 octahedra, corners with six equivalent Y(1)S6 octahedra,  an edgeedge with one Y(1)S6 octahedra, edges with three equivalent Y(3)S6 octahedra, edges with two equivalent Y(2)S7 pentagonal bipyramids, and faces with two equivalent Y(2)S7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 22-68°. Both Y(2)-S(1) bond lengths are 2.94 Å. Both Y(2)-S(2) bond lengths are 2.74 Å. There are two shorter (2.83 Å) and one longer (2.95 Å) Y(2)-S(3) bond length. In the third Y site, Y(3) is bonded to two equivalent S(2) and four equivalent S(3) atoms to form YS6 octahedra that share corners with two equivalent Y(1)S6 octahedra, corners with four equivalent Y(2)S7 pentagonal bipyramids, edges with two equivalent Y(3)S6 octahedra, and edges with six equivalent Y(2)S7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 56°. Both Y(3)-S(2) bond lengths are 2.68 Å. All Y(3)-S(3) bond lengths are 2.74 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Y(2) and three equivalent Y(1) atoms to form SY5 trigonal bipyramids that share corners with five equivalent S(2)Y4 tetrahedra, corners with four equivalent S(3)Y5 trigonal bipyramids,  an edgeedge with one S(2)Y4 tetrahedra,  an edgeedge with one S(3)Y5 trigonal bipyramid, and edges with four equivalent S(1)Y5 trigonal bipyramids. In the second S site, S(2) is bonded to one Y(1), one Y(3), and two equivalent Y(2) atoms to form distorted SY4 tetrahedra that share corners with three equivalent S(2)Y4 tetrahedra, corners with four equivalent S(3)Y5 trigonal bipyramids, corners with five equivalent S(1)Y5 trigonal bipyramids,  an edgeedge with one S(1)Y5 trigonal bipyramid, and edges with three equivalent S(3)Y5 trigonal bipyramids. In the third S site, S(3) is bonded to two equivalent Y(3) and three equivalent Y(2) atoms to form distorted SY5 trigonal bipyramids that share corners with four equivalent S(2)Y4 tetrahedra, corners with two equivalent S(3)Y5 trigonal bipyramids, corners with four equivalent S(1)Y5 trigonal bipyramids, edges with three equivalent S(2)Y4 tetrahedra,  an edgeedge with one S(1)Y5 trigonal bipyramid, and edges with five equivalent S(3)Y5 trigonal bipyramids. In the fourth S site, S(4) is bonded in a square co-planar geometry to four equivalent Y(1) atoms.