U8CoS17 crystallizes in the monoclinic C2/m space group. There are three inequivalent U sites. In the first U site, U(1) is bonded in a 8-coordinate geometry to one S(2), one S(3), one S(4), one S(5), one S(6), one S(7), and two equivalent S(1) atoms. In the second U site, U(2) is bonded in a 8-coordinate geometry to one S(3), one S(4), one S(5), one S(7), and four equivalent S(1) atoms. In the third U site, U(3) is bonded in a 8-coordinate geometry to one S(4), one S(5), two equivalent S(6), and four equivalent S(2) atoms. Co(1) is bonded in an octahedral geometry to two equivalent S(3) and four equivalent S(2) atoms. There are seven inequivalent S sites. In the first S site, S(6) is bonded to two equivalent U(1) and two equivalent U(3) atoms to form distorted SU4 trigonal pyramids that share corners with two equivalent S(7)U6 octahedra, corners with six equivalent S(2)U3Co tetrahedra, corners with two equivalent S(3)U3Co trigonal pyramids, edges with two equivalent S(2)U3Co tetrahedra, and  an edgeedge with one S(6)U4 trigonal pyramid. The corner-sharing octahedral tilt angles are 37°. In the second S site, S(7) is bonded to two equivalent U(2) and four equivalent U(1) atoms to form SU6 octahedra that share corners with four equivalent S(2)U3Co tetrahedra, corners with four equivalent S(6)U4 trigonal pyramids, and faces with two equivalent S(3)U3Co trigonal pyramids. In the third S site, S(1) is bonded in a rectangular see-saw-like geometry to two equivalent U(1) and two equivalent U(2) atoms. In the fourth S site, S(2) is bonded to one U(1), two equivalent U(3), and one Co(1) atom to form distorted SU3Co tetrahedra that share  a cornercorner with one S(7)U6 octahedra, corners with five equivalent S(2)U3Co tetrahedra,  a cornercorner with one S(3)U3Co trigonal pyramid, corners with three equivalent S(6)U4 trigonal pyramids, edges with two equivalent S(2)U3Co tetrahedra,  an edgeedge with one S(3)U3Co trigonal pyramid, and  an edgeedge with one S(6)U4 trigonal pyramid. The corner-sharing octahedral tilt angles are 53°. In the fifth S site, S(3) is bonded to one U(2), two equivalent U(1), and one Co(1) atom to form distorted SU3Co trigonal pyramids that share corners with two equivalent S(2)U3Co tetrahedra,  a cornercorner with one S(3)U3Co trigonal pyramid, corners with two equivalent S(6)U4 trigonal pyramids, edges with two equivalent S(2)U3Co tetrahedra, and  a faceface with one S(7)U6 octahedra. In the sixth S site, S(4) is bonded in a rectangular see-saw-like geometry to one U(2), one U(3), and two equivalent U(1) atoms. In the seventh S site, S(5) is bonded in a rectangular see-saw-like geometry to one U(2), one U(3), and two equivalent U(1) atoms.
U8CoS17 crystallizes in the monoclinic C2/m space group. There are three inequivalent U sites. In the first U site, U(1) is bonded in a 8-coordinate geometry to one S(2), one S(3), one S(4), one S(5), one S(6), one S(7), and two equivalent S(1) atoms. The U(1)-S(2) bond length is 2.76 Å. The U(1)-S(3) bond length is 2.72 Å. The U(1)-S(4) bond length is 2.86 Å. The U(1)-S(5) bond length is 2.84 Å. The U(1)-S(6) bond length is 2.80 Å. The U(1)-S(7) bond length is 2.98 Å. There is one shorter (2.80 Å) and one longer (2.89 Å) U(1)-S(1) bond length. In the second U site, U(2) is bonded in a 8-coordinate geometry to one S(3), one S(4), one S(5), one S(7), and four equivalent S(1) atoms. The U(2)-S(3) bond length is 2.83 Å. The U(2)-S(4) bond length is 2.74 Å. The U(2)-S(5) bond length is 2.74 Å. The U(2)-S(7) bond length is 2.86 Å. There are two shorter (2.77 Å) and two longer (2.78 Å) U(2)-S(1) bond lengths. In the third U site, U(3) is bonded in a 8-coordinate geometry to one S(4), one S(5), two equivalent S(6), and four equivalent S(2) atoms. The U(3)-S(4) bond length is 2.78 Å. The U(3)-S(5) bond length is 2.77 Å. There is one shorter (2.93 Å) and one longer (2.99 Å) U(3)-S(6) bond length. There are two shorter (2.73 Å) and two longer (2.92 Å) U(3)-S(2) bond lengths. Co(1) is bonded in an octahedral geometry to two equivalent S(3) and four equivalent S(2) atoms. Both Co(1)-S(3) bond lengths are 2.24 Å. All Co(1)-S(2) bond lengths are 2.44 Å. There are seven inequivalent S sites. In the first S site, S(6) is bonded to two equivalent U(1) and two equivalent U(3) atoms to form distorted SU4 trigonal pyramids that share corners with two equivalent S(7)U6 octahedra, corners with six equivalent S(2)U3Co tetrahedra, corners with two equivalent S(3)U3Co trigonal pyramids, edges with two equivalent S(2)U3Co tetrahedra, and  an edgeedge with one S(6)U4 trigonal pyramid. The corner-sharing octahedral tilt angles are 37°. In the second S site, S(7) is bonded to two equivalent U(2) and four equivalent U(1) atoms to form SU6 octahedra that share corners with four equivalent S(2)U3Co tetrahedra, corners with four equivalent S(6)U4 trigonal pyramids, and faces with two equivalent S(3)U3Co trigonal pyramids. In the third S site, S(1) is bonded in a rectangular see-saw-like geometry to two equivalent U(1) and two equivalent U(2) atoms. In the fourth S site, S(2) is bonded to one U(1), two equivalent U(3), and one Co(1) atom to form distorted SU3Co tetrahedra that share  a cornercorner with one S(7)U6 octahedra, corners with five equivalent S(2)U3Co tetrahedra,  a cornercorner with one S(3)U3Co trigonal pyramid, corners with three equivalent S(6)U4 trigonal pyramids, edges with two equivalent S(2)U3Co tetrahedra,  an edgeedge with one S(3)U3Co trigonal pyramid, and  an edgeedge with one S(6)U4 trigonal pyramid. The corner-sharing octahedral tilt angles are 53°. In the fifth S site, S(3) is bonded to one U(2), two equivalent U(1), and one Co(1) atom to form distorted SU3Co trigonal pyramids that share corners with two equivalent S(2)U3Co tetrahedra,  a cornercorner with one S(3)U3Co trigonal pyramid, corners with two equivalent S(6)U4 trigonal pyramids, edges with two equivalent S(2)U3Co tetrahedra, and  a faceface with one S(7)U6 octahedra. In the sixth S site, S(4) is bonded in a rectangular see-saw-like geometry to one U(2), one U(3), and two equivalent U(1) atoms. In the seventh S site, S(5) is bonded in a rectangular see-saw-like geometry to one U(2), one U(3), and two equivalent U(1) atoms.