Ho4FeS7 crystallizes in the monoclinic Cm space group. There are four inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 7-coordinate geometry to one S(4), two equivalent S(2), two equivalent S(3), and two equivalent S(5) atoms. In the second Ho site, Ho(2) is bonded in a 7-coordinate geometry to one S(3), two equivalent S(1), two equivalent S(4), and two equivalent S(6) atoms. In the third Ho site, Ho(3) is bonded to one S(5), one S(6), two equivalent S(3), and two equivalent S(4) atoms to form HoS6 octahedra that share  a cornercorner with one Ho(4)S6 octahedra,  a cornercorner with one Fe(1)S6 octahedra, and edges with two equivalent Ho(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 50-52°. In the fourth Ho site, Ho(4) is bonded to one S(2), one S(6), two equivalent S(1), and two equivalent S(7) atoms to form HoS6 octahedra that share  a cornercorner with one Ho(3)S6 octahedra, corners with two equivalent Fe(1)S6 octahedra, edges with two equivalent Ho(4)S6 octahedra, and edges with three equivalent Fe(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 4-50°. Fe(1) is bonded to one S(1), one S(5), two equivalent S(2), and two equivalent S(7) atoms to form FeS6 octahedra that share  a cornercorner with one Ho(3)S6 octahedra, corners with two equivalent Ho(4)S6 octahedra, edges with two equivalent Fe(1)S6 octahedra, and edges with three equivalent Ho(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 4-52°. There are seven inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Ho(2), two equivalent Ho(4), and one Fe(1) atom to form SHo4Fe trigonal bipyramids that share  a cornercorner with one S(5)Ho3Fe tetrahedra, corners with four equivalent S(6)Ho4 tetrahedra, corners with two equivalent S(3)Ho5 trigonal bipyramids, corners with two equivalent S(4)Ho5 trigonal bipyramids, edges with two equivalent S(2)Ho3Fe2 square pyramids,  an edgeedge with one S(6)Ho4 tetrahedra,  an edgeedge with one S(4)Ho5 trigonal bipyramid, and edges with two equivalent S(1)Ho4Fe trigonal bipyramids. In the second S site, S(2) is bonded to one Ho(4), two equivalent Ho(1), and two equivalent Fe(1) atoms to form SHo3Fe2 square pyramids that share  a cornercorner with one S(6)Ho4 tetrahedra, corners with four equivalent S(5)Ho3Fe tetrahedra, corners with two equivalent S(3)Ho5 trigonal bipyramids, corners with two equivalent S(4)Ho5 trigonal bipyramids, edges with two equivalent S(2)Ho3Fe2 square pyramids,  an edgeedge with one S(5)Ho3Fe tetrahedra,  an edgeedge with one S(3)Ho5 trigonal bipyramid, and edges with two equivalent S(1)Ho4Fe trigonal bipyramids. In the third S site, S(3) is bonded to one Ho(2), two equivalent Ho(1), and two equivalent Ho(3) atoms to form distorted SHo5 trigonal bipyramids that share corners with two equivalent S(2)Ho3Fe2 square pyramids, corners with four equivalent S(5)Ho3Fe tetrahedra, corners with two equivalent S(1)Ho4Fe trigonal bipyramids, corners with two equivalent S(4)Ho5 trigonal bipyramids,  an edgeedge with one S(2)Ho3Fe2 square pyramid,  an edgeedge with one S(5)Ho3Fe tetrahedra, edges with two equivalent S(6)Ho4 tetrahedra, edges with two equivalent S(3)Ho5 trigonal bipyramids, and edges with three equivalent S(4)Ho5 trigonal bipyramids. In the fourth S site, S(4) is bonded to one Ho(1), two equivalent Ho(2), and two equivalent Ho(3) atoms to form distorted SHo5 trigonal bipyramids that share corners with two equivalent S(2)Ho3Fe2 square pyramids, corners with four equivalent S(6)Ho4 tetrahedra, corners with two equivalent S(1)Ho4Fe trigonal bipyramids, corners with two equivalent S(3)Ho5 trigonal bipyramids,  an edgeedge with one S(6)Ho4 tetrahedra, edges with two equivalent S(5)Ho3Fe tetrahedra,  an edgeedge with one S(1)Ho4Fe trigonal bipyramid, edges with two equivalent S(4)Ho5 trigonal bipyramids, and edges with three equivalent S(3)Ho5 trigonal bipyramids. In the fifth S site, S(5) is bonded to one Ho(3), two equivalent Ho(1), and one Fe(1) atom to form distorted SHo3Fe tetrahedra that share corners with four equivalent S(2)Ho3Fe2 square pyramids,  a cornercorner with one S(6)Ho4 tetrahedra, corners with two equivalent S(5)Ho3Fe tetrahedra,  a cornercorner with one S(1)Ho4Fe trigonal bipyramid, corners with four equivalent S(3)Ho5 trigonal bipyramids,  an edgeedge with one S(2)Ho3Fe2 square pyramid,  an edgeedge with one S(3)Ho5 trigonal bipyramid, and edges with two equivalent S(4)Ho5 trigonal bipyramids. In the sixth S site, S(6) is bonded to one Ho(3), one Ho(4), and two equivalent Ho(2) atoms to form SHo4 tetrahedra that share  a cornercorner with one S(2)Ho3Fe2 square pyramid,  a cornercorner with one S(5)Ho3Fe tetrahedra, corners with two equivalent S(6)Ho4 tetrahedra, corners with four equivalent S(1)Ho4Fe trigonal bipyramids, corners with four equivalent S(4)Ho5 trigonal bipyramids,  an edgeedge with one S(1)Ho4Fe trigonal bipyramid,  an edgeedge with one S(4)Ho5 trigonal bipyramid, and edges with two equivalent S(3)Ho5 trigonal bipyramids. In the seventh S site, S(7) is bonded in a rectangular see-saw-like geometry to two equivalent Ho(4) and two equivalent Fe(1) atoms.
Ho4FeS7 crystallizes in the monoclinic Cm space group. There are four inequivalent Ho sites. In the first Ho site, Ho(1) is bonded in a 7-coordinate geometry to one S(4), two equivalent S(2), two equivalent S(3), and two equivalent S(5) atoms. The Ho(1)-S(4) bond length is 3.08 Å. Both Ho(1)-S(2) bond lengths are 2.83 Å. Both Ho(1)-S(3) bond lengths are 2.87 Å. Both Ho(1)-S(5) bond lengths are 2.72 Å. In the second Ho site, Ho(2) is bonded in a 7-coordinate geometry to one S(3), two equivalent S(1), two equivalent S(4), and two equivalent S(6) atoms. The Ho(2)-S(3) bond length is 2.99 Å. Both Ho(2)-S(1) bond lengths are 2.87 Å. Both Ho(2)-S(4) bond lengths are 2.85 Å. Both Ho(2)-S(6) bond lengths are 2.69 Å. In the third Ho site, Ho(3) is bonded to one S(5), one S(6), two equivalent S(3), and two equivalent S(4) atoms to form HoS6 octahedra that share  a cornercorner with one Ho(4)S6 octahedra,  a cornercorner with one Fe(1)S6 octahedra, and edges with two equivalent Ho(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 50-52°. The Ho(3)-S(5) bond length is 2.65 Å. The Ho(3)-S(6) bond length is 2.67 Å. Both Ho(3)-S(3) bond lengths are 2.70 Å. Both Ho(3)-S(4) bond lengths are 2.70 Å. In the fourth Ho site, Ho(4) is bonded to one S(2), one S(6), two equivalent S(1), and two equivalent S(7) atoms to form HoS6 octahedra that share  a cornercorner with one Ho(3)S6 octahedra, corners with two equivalent Fe(1)S6 octahedra, edges with two equivalent Ho(4)S6 octahedra, and edges with three equivalent Fe(1)S6 octahedra. The corner-sharing octahedral tilt angles range from 4-50°. The Ho(4)-S(2) bond length is 2.69 Å. The Ho(4)-S(6) bond length is 2.71 Å. Both Ho(4)-S(1) bond lengths are 2.77 Å. Both Ho(4)-S(7) bond lengths are 2.66 Å. Fe(1) is bonded to one S(1), one S(5), two equivalent S(2), and two equivalent S(7) atoms to form FeS6 octahedra that share  a cornercorner with one Ho(3)S6 octahedra, corners with two equivalent Ho(4)S6 octahedra, edges with two equivalent Fe(1)S6 octahedra, and edges with three equivalent Ho(4)S6 octahedra. The corner-sharing octahedral tilt angles range from 4-52°. The Fe(1)-S(1) bond length is 2.61 Å. The Fe(1)-S(5) bond length is 2.47 Å. Both Fe(1)-S(2) bond lengths are 2.63 Å. Both Fe(1)-S(7) bond lengths are 2.50 Å. There are seven inequivalent S sites. In the first S site, S(1) is bonded to two equivalent Ho(2), two equivalent Ho(4), and one Fe(1) atom to form SHo4Fe trigonal bipyramids that share  a cornercorner with one S(5)Ho3Fe tetrahedra, corners with four equivalent S(6)Ho4 tetrahedra, corners with two equivalent S(3)Ho5 trigonal bipyramids, corners with two equivalent S(4)Ho5 trigonal bipyramids, edges with two equivalent S(2)Ho3Fe2 square pyramids,  an edgeedge with one S(6)Ho4 tetrahedra,  an edgeedge with one S(4)Ho5 trigonal bipyramid, and edges with two equivalent S(1)Ho4Fe trigonal bipyramids. In the second S site, S(2) is bonded to one Ho(4), two equivalent Ho(1), and two equivalent Fe(1) atoms to form SHo3Fe2 square pyramids that share  a cornercorner with one S(6)Ho4 tetrahedra, corners with four equivalent S(5)Ho3Fe tetrahedra, corners with two equivalent S(3)Ho5 trigonal bipyramids, corners with two equivalent S(4)Ho5 trigonal bipyramids, edges with two equivalent S(2)Ho3Fe2 square pyramids,  an edgeedge with one S(5)Ho3Fe tetrahedra,  an edgeedge with one S(3)Ho5 trigonal bipyramid, and edges with two equivalent S(1)Ho4Fe trigonal bipyramids. In the third S site, S(3) is bonded to one Ho(2), two equivalent Ho(1), and two equivalent Ho(3) atoms to form distorted SHo5 trigonal bipyramids that share corners with two equivalent S(2)Ho3Fe2 square pyramids, corners with four equivalent S(5)Ho3Fe tetrahedra, corners with two equivalent S(1)Ho4Fe trigonal bipyramids, corners with two equivalent S(4)Ho5 trigonal bipyramids,  an edgeedge with one S(2)Ho3Fe2 square pyramid,  an edgeedge with one S(5)Ho3Fe tetrahedra, edges with two equivalent S(6)Ho4 tetrahedra, edges with two equivalent S(3)Ho5 trigonal bipyramids, and edges with three equivalent S(4)Ho5 trigonal bipyramids. In the fourth S site, S(4) is bonded to one Ho(1), two equivalent Ho(2), and two equivalent Ho(3) atoms to form distorted SHo5 trigonal bipyramids that share corners with two equivalent S(2)Ho3Fe2 square pyramids, corners with four equivalent S(6)Ho4 tetrahedra, corners with two equivalent S(1)Ho4Fe trigonal bipyramids, corners with two equivalent S(3)Ho5 trigonal bipyramids,  an edgeedge with one S(6)Ho4 tetrahedra, edges with two equivalent S(5)Ho3Fe tetrahedra,  an edgeedge with one S(1)Ho4Fe trigonal bipyramid, edges with two equivalent S(4)Ho5 trigonal bipyramids, and edges with three equivalent S(3)Ho5 trigonal bipyramids. In the fifth S site, S(5) is bonded to one Ho(3), two equivalent Ho(1), and one Fe(1) atom to form distorted SHo3Fe tetrahedra that share corners with four equivalent S(2)Ho3Fe2 square pyramids,  a cornercorner with one S(6)Ho4 tetrahedra, corners with two equivalent S(5)Ho3Fe tetrahedra,  a cornercorner with one S(1)Ho4Fe trigonal bipyramid, corners with four equivalent S(3)Ho5 trigonal bipyramids,  an edgeedge with one S(2)Ho3Fe2 square pyramid,  an edgeedge with one S(3)Ho5 trigonal bipyramid, and edges with two equivalent S(4)Ho5 trigonal bipyramids. In the sixth S site, S(6) is bonded to one Ho(3), one Ho(4), and two equivalent Ho(2) atoms to form SHo4 tetrahedra that share  a cornercorner with one S(2)Ho3Fe2 square pyramid,  a cornercorner with one S(5)Ho3Fe tetrahedra, corners with two equivalent S(6)Ho4 tetrahedra, corners with four equivalent S(1)Ho4Fe trigonal bipyramids, corners with four equivalent S(4)Ho5 trigonal bipyramids,  an edgeedge with one S(1)Ho4Fe trigonal bipyramid,  an edgeedge with one S(4)Ho5 trigonal bipyramid, and edges with two equivalent S(3)Ho5 trigonal bipyramids. In the seventh S site, S(7) is bonded in a rectangular see-saw-like geometry to two equivalent Ho(4) and two equivalent Fe(1) atoms.