Tm15S22 crystallizes in the monoclinic C2/m space group. There are eight inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to one S(8), two equivalent S(5), and three equivalent S(4) atoms to form TmS6 octahedra that share corners with three equivalent Tm(7)S6 octahedra,  a cornercorner with one Tm(6)S7 pentagonal bipyramid, edges with four equivalent Tm(1)S6 octahedra, and edges with two equivalent Tm(6)S7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 54-60°. In the second Tm site, Tm(2) is bonded to one S(7), one S(9), two equivalent S(11), and two equivalent S(2) atoms to form a mixture of edge and corner-sharing TmS6 octahedra. The corner-sharing octahedral tilt angles range from 48-59°. In the third Tm site, Tm(3) is bonded in a 8-coordinate geometry to one S(1), one S(6), two equivalent S(10), two equivalent S(11), and two equivalent S(3) atoms. In the fourth Tm site, Tm(4) is bonded to one S(2), one S(3), two equivalent S(1), and two equivalent S(7) atoms to form a mixture of edge and corner-sharing TmS6 octahedra. The corner-sharing octahedral tilt angles range from 48-59°. In the fifth Tm site, Tm(5) is bonded in a 7-coordinate geometry to one S(10), two equivalent S(1), two equivalent S(5), and two equivalent S(9) atoms. In the sixth Tm site, Tm(6) is bonded to one S(5), one S(6), two equivalent S(10), and three equivalent S(8) atoms to form distorted TmS7 pentagonal bipyramids that share  a cornercorner with one Tm(1)S6 octahedra, corners with two equivalent Tm(7)S6 octahedra, edges with two equivalent Tm(1)S6 octahedra, and edges with four equivalent Tm(6)S7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-50°. In the seventh Tm site, Tm(7) is bonded to one S(11), one S(4), two equivalent S(6), and two equivalent S(9) atoms to form TmS6 octahedra that share corners with three equivalent Tm(1)S6 octahedra, corners with two equivalent Tm(6)S7 pentagonal bipyramids, edges with two equivalent Tm(2)S6 octahedra, and edges with two equivalent Tm(7)S6 octahedra. The corner-sharing octahedral tilt angles range from 54-60°. In the eighth Tm site, Tm(8) is bonded to two equivalent S(7) and four equivalent S(3) atoms to form a mixture of edge and corner-sharing TmS6 octahedra. The corner-sharing octahedral tilt angles are 56°. There are eleven inequivalent S sites. In the first S site, S(1) is bonded to one Tm(3), two equivalent Tm(4), and two equivalent Tm(5) atoms to form distorted STm5 trigonal bipyramids that share corners with two equivalent S(11)Tm5 square pyramids, corners with two equivalent S(5)Tm5 trigonal bipyramids, corners with two equivalent S(9)Tm5 trigonal bipyramids,  a cornercorner with one S(6)Tm4 trigonal pyramid, edges with two equivalent S(3)Tm5 square pyramids,  an edgeedge with one S(5)Tm5 trigonal bipyramid,  an edgeedge with one S(9)Tm5 trigonal bipyramid, edges with two equivalent S(1)Tm5 trigonal bipyramids, and edges with two equivalent S(10)Tm5 trigonal bipyramids. In the second S site, S(2) is bonded in a 3-coordinate geometry to one Tm(4) and two equivalent Tm(2) atoms. In the third S site, S(3) is bonded to one Tm(4), two equivalent Tm(3), and two equivalent Tm(8) atoms to form STm5 square pyramids that share corners with two equivalent S(11)Tm5 square pyramids, corners with two equivalent S(3)Tm5 square pyramids, corners with two equivalent S(10)Tm5 trigonal bipyramids, corners with two equivalent S(6)Tm4 trigonal pyramids,  an edgeedge with one S(11)Tm5 square pyramid, edges with three equivalent S(3)Tm5 square pyramids,  an edgeedge with one S(10)Tm5 trigonal bipyramid, and edges with two equivalent S(1)Tm5 trigonal bipyramids. In the fourth S site, S(4) is bonded in a rectangular see-saw-like geometry to one Tm(7) and three equivalent Tm(1) atoms. In the fifth S site, S(5) is bonded to one Tm(6), two equivalent Tm(1), and two equivalent Tm(5) atoms to form STm5 trigonal bipyramids that share corners with two equivalent S(1)Tm5 trigonal bipyramids, corners with two equivalent S(9)Tm5 trigonal bipyramids,  a cornercorner with one S(6)Tm4 trigonal pyramid,  a cornercorner with one S(8)Tm4 trigonal pyramid,  an edgeedge with one S(1)Tm5 trigonal bipyramid,  an edgeedge with one S(9)Tm5 trigonal bipyramid, edges with two equivalent S(10)Tm5 trigonal bipyramids, edges with two equivalent S(5)Tm5 trigonal bipyramids, and edges with two equivalent S(8)Tm4 trigonal pyramids. In the sixth S site, S(6) is bonded to one Tm(3), one Tm(6), and two equivalent Tm(7) atoms to form distorted STm4 trigonal pyramids that share corners with two equivalent S(3)Tm5 square pyramids,  a cornercorner with one S(1)Tm5 trigonal bipyramid,  a cornercorner with one S(5)Tm5 trigonal bipyramid, corners with two equivalent S(9)Tm5 trigonal bipyramids, corners with two equivalent S(6)Tm4 trigonal pyramids, corners with three equivalent S(8)Tm4 trigonal pyramids, edges with two equivalent S(11)Tm5 square pyramids,  an edgeedge with one S(9)Tm5 trigonal bipyramid, and edges with two equivalent S(10)Tm5 trigonal bipyramids. In the seventh S site, S(7) is bonded in a rectangular see-saw-like geometry to one Tm(2), one Tm(8), and two equivalent Tm(4) atoms. In the eighth S site, S(8) is bonded to one Tm(1) and three equivalent Tm(6) atoms to form distorted STm4 trigonal pyramids that share  a cornercorner with one S(5)Tm5 trigonal bipyramid, corners with four equivalent S(10)Tm5 trigonal bipyramids, corners with two equivalent S(8)Tm4 trigonal pyramids, corners with three equivalent S(6)Tm4 trigonal pyramids,  an edgeedge with one S(10)Tm5 trigonal bipyramid, edges with two equivalent S(5)Tm5 trigonal bipyramids, and edges with two equivalent S(8)Tm4 trigonal pyramids. In the ninth S site, S(9) is bonded to one Tm(2), two equivalent Tm(5), and two equivalent Tm(7) atoms to form STm5 trigonal bipyramids that share corners with two equivalent S(1)Tm5 trigonal bipyramids, corners with two equivalent S(10)Tm5 trigonal bipyramids, corners with two equivalent S(5)Tm5 trigonal bipyramids, corners with two equivalent S(6)Tm4 trigonal pyramids, edges with two equivalent S(11)Tm5 square pyramids,  an edgeedge with one S(1)Tm5 trigonal bipyramid,  an edgeedge with one S(5)Tm5 trigonal bipyramid, edges with two equivalent S(9)Tm5 trigonal bipyramids, and  an edgeedge with one S(6)Tm4 trigonal pyramid. In the tenth S site, S(10) is bonded to one Tm(5), two equivalent Tm(3), and two equivalent Tm(6) atoms to form distorted STm5 trigonal bipyramids that share corners with two equivalent S(11)Tm5 square pyramids, corners with two equivalent S(3)Tm5 square pyramids, corners with two equivalent S(9)Tm5 trigonal bipyramids, corners with four equivalent S(8)Tm4 trigonal pyramids,  an edgeedge with one S(11)Tm5 square pyramid,  an edgeedge with one S(3)Tm5 square pyramid, edges with two equivalent S(1)Tm5 trigonal bipyramids, edges with two equivalent S(10)Tm5 trigonal bipyramids, edges with two equivalent S(5)Tm5 trigonal bipyramids,  an edgeedge with one S(8)Tm4 trigonal pyramid, and edges with two equivalent S(6)Tm4 trigonal pyramids. In the eleventh S site, S(11) is bonded to one Tm(7), two equivalent Tm(2), and two equivalent Tm(3) atoms to form STm5 square pyramids that share corners with two equivalent S(3)Tm5 square pyramids, corners with two equivalent S(1)Tm5 trigonal bipyramids, corners with two equivalent S(10)Tm5 trigonal bipyramids,  an edgeedge with one S(3)Tm5 square pyramid, edges with two equivalent S(11)Tm5 square pyramids,  an edgeedge with one S(10)Tm5 trigonal bipyramid, edges with two equivalent S(9)Tm5 trigonal bipyramids, and edges with two equivalent S(6)Tm4 trigonal pyramids.
Tm15S22 crystallizes in the monoclinic C2/m space group. There are eight inequivalent Tm sites. In the first Tm site, Tm(1) is bonded to one S(8), two equivalent S(5), and three equivalent S(4) atoms to form TmS6 octahedra that share corners with three equivalent Tm(7)S6 octahedra,  a cornercorner with one Tm(6)S7 pentagonal bipyramid, edges with four equivalent Tm(1)S6 octahedra, and edges with two equivalent Tm(6)S7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 54-60°. The Tm(1)-S(8) bond length is 2.63 Å. Both Tm(1)-S(5) bond lengths are 2.73 Å. There are two shorter (2.68 Å) and one longer (2.72 Å) Tm(1)-S(4) bond length. In the second Tm site, Tm(2) is bonded to one S(7), one S(9), two equivalent S(11), and two equivalent S(2) atoms to form a mixture of edge and corner-sharing TmS6 octahedra. The corner-sharing octahedral tilt angles range from 48-59°. The Tm(2)-S(7) bond length is 2.71 Å. The Tm(2)-S(9) bond length is 2.74 Å. Both Tm(2)-S(11) bond lengths are 2.73 Å. Both Tm(2)-S(2) bond lengths are 2.60 Å. In the third Tm site, Tm(3) is bonded in a 8-coordinate geometry to one S(1), one S(6), two equivalent S(10), two equivalent S(11), and two equivalent S(3) atoms. The Tm(3)-S(1) bond length is 2.94 Å. The Tm(3)-S(6) bond length is 2.82 Å. Both Tm(3)-S(10) bond lengths are 2.78 Å. Both Tm(3)-S(11) bond lengths are 2.96 Å. Both Tm(3)-S(3) bond lengths are 2.93 Å. In the fourth Tm site, Tm(4) is bonded to one S(2), one S(3), two equivalent S(1), and two equivalent S(7) atoms to form a mixture of edge and corner-sharing TmS6 octahedra. The corner-sharing octahedral tilt angles range from 48-59°. The Tm(4)-S(2) bond length is 2.58 Å. The Tm(4)-S(3) bond length is 2.72 Å. Both Tm(4)-S(1) bond lengths are 2.75 Å. Both Tm(4)-S(7) bond lengths are 2.67 Å. In the fifth Tm site, Tm(5) is bonded in a 7-coordinate geometry to one S(10), two equivalent S(1), two equivalent S(5), and two equivalent S(9) atoms. The Tm(5)-S(10) bond length is 2.84 Å. Both Tm(5)-S(1) bond lengths are 2.77 Å. Both Tm(5)-S(5) bond lengths are 2.83 Å. Both Tm(5)-S(9) bond lengths are 2.92 Å. In the sixth Tm site, Tm(6) is bonded to one S(5), one S(6), two equivalent S(10), and three equivalent S(8) atoms to form distorted TmS7 pentagonal bipyramids that share  a cornercorner with one Tm(1)S6 octahedra, corners with two equivalent Tm(7)S6 octahedra, edges with two equivalent Tm(1)S6 octahedra, and edges with four equivalent Tm(6)S7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 38-50°. The Tm(6)-S(5) bond length is 2.86 Å. The Tm(6)-S(6) bond length is 2.68 Å. Both Tm(6)-S(10) bond lengths are 2.86 Å. There are two shorter (2.66 Å) and one longer (2.85 Å) Tm(6)-S(8) bond length. In the seventh Tm site, Tm(7) is bonded to one S(11), one S(4), two equivalent S(6), and two equivalent S(9) atoms to form TmS6 octahedra that share corners with three equivalent Tm(1)S6 octahedra, corners with two equivalent Tm(6)S7 pentagonal bipyramids, edges with two equivalent Tm(2)S6 octahedra, and edges with two equivalent Tm(7)S6 octahedra. The corner-sharing octahedral tilt angles range from 54-60°. The Tm(7)-S(11) bond length is 2.69 Å. The Tm(7)-S(4) bond length is 2.67 Å. Both Tm(7)-S(6) bond lengths are 2.63 Å. Both Tm(7)-S(9) bond lengths are 2.76 Å. In the eighth Tm site, Tm(8) is bonded to two equivalent S(7) and four equivalent S(3) atoms to form a mixture of edge and corner-sharing TmS6 octahedra. The corner-sharing octahedral tilt angles are 56°. Both Tm(8)-S(7) bond lengths are 2.68 Å. All Tm(8)-S(3) bond lengths are 2.72 Å. There are eleven inequivalent S sites. In the first S site, S(1) is bonded to one Tm(3), two equivalent Tm(4), and two equivalent Tm(5) atoms to form distorted STm5 trigonal bipyramids that share corners with two equivalent S(11)Tm5 square pyramids, corners with two equivalent S(5)Tm5 trigonal bipyramids, corners with two equivalent S(9)Tm5 trigonal bipyramids,  a cornercorner with one S(6)Tm4 trigonal pyramid, edges with two equivalent S(3)Tm5 square pyramids,  an edgeedge with one S(5)Tm5 trigonal bipyramid,  an edgeedge with one S(9)Tm5 trigonal bipyramid, edges with two equivalent S(1)Tm5 trigonal bipyramids, and edges with two equivalent S(10)Tm5 trigonal bipyramids. In the second S site, S(2) is bonded in a 3-coordinate geometry to one Tm(4) and two equivalent Tm(2) atoms. In the third S site, S(3) is bonded to one Tm(4), two equivalent Tm(3), and two equivalent Tm(8) atoms to form STm5 square pyramids that share corners with two equivalent S(11)Tm5 square pyramids, corners with two equivalent S(3)Tm5 square pyramids, corners with two equivalent S(10)Tm5 trigonal bipyramids, corners with two equivalent S(6)Tm4 trigonal pyramids,  an edgeedge with one S(11)Tm5 square pyramid, edges with three equivalent S(3)Tm5 square pyramids,  an edgeedge with one S(10)Tm5 trigonal bipyramid, and edges with two equivalent S(1)Tm5 trigonal bipyramids. In the fourth S site, S(4) is bonded in a rectangular see-saw-like geometry to one Tm(7) and three equivalent Tm(1) atoms. In the fifth S site, S(5) is bonded to one Tm(6), two equivalent Tm(1), and two equivalent Tm(5) atoms to form STm5 trigonal bipyramids that share corners with two equivalent S(1)Tm5 trigonal bipyramids, corners with two equivalent S(9)Tm5 trigonal bipyramids,  a cornercorner with one S(6)Tm4 trigonal pyramid,  a cornercorner with one S(8)Tm4 trigonal pyramid,  an edgeedge with one S(1)Tm5 trigonal bipyramid,  an edgeedge with one S(9)Tm5 trigonal bipyramid, edges with two equivalent S(10)Tm5 trigonal bipyramids, edges with two equivalent S(5)Tm5 trigonal bipyramids, and edges with two equivalent S(8)Tm4 trigonal pyramids. In the sixth S site, S(6) is bonded to one Tm(3), one Tm(6), and two equivalent Tm(7) atoms to form distorted STm4 trigonal pyramids that share corners with two equivalent S(3)Tm5 square pyramids,  a cornercorner with one S(1)Tm5 trigonal bipyramid,  a cornercorner with one S(5)Tm5 trigonal bipyramid, corners with two equivalent S(9)Tm5 trigonal bipyramids, corners with two equivalent S(6)Tm4 trigonal pyramids, corners with three equivalent S(8)Tm4 trigonal pyramids, edges with two equivalent S(11)Tm5 square pyramids,  an edgeedge with one S(9)Tm5 trigonal bipyramid, and edges with two equivalent S(10)Tm5 trigonal bipyramids. In the seventh S site, S(7) is bonded in a rectangular see-saw-like geometry to one Tm(2), one Tm(8), and two equivalent Tm(4) atoms. In the eighth S site, S(8) is bonded to one Tm(1) and three equivalent Tm(6) atoms to form distorted STm4 trigonal pyramids that share  a cornercorner with one S(5)Tm5 trigonal bipyramid, corners with four equivalent S(10)Tm5 trigonal bipyramids, corners with two equivalent S(8)Tm4 trigonal pyramids, corners with three equivalent S(6)Tm4 trigonal pyramids,  an edgeedge with one S(10)Tm5 trigonal bipyramid, edges with two equivalent S(5)Tm5 trigonal bipyramids, and edges with two equivalent S(8)Tm4 trigonal pyramids. In the ninth S site, S(9) is bonded to one Tm(2), two equivalent Tm(5), and two equivalent Tm(7) atoms to form STm5 trigonal bipyramids that share corners with two equivalent S(1)Tm5 trigonal bipyramids, corners with two equivalent S(10)Tm5 trigonal bipyramids, corners with two equivalent S(5)Tm5 trigonal bipyramids, corners with two equivalent S(6)Tm4 trigonal pyramids, edges with two equivalent S(11)Tm5 square pyramids,  an edgeedge with one S(1)Tm5 trigonal bipyramid,  an edgeedge with one S(5)Tm5 trigonal bipyramid, edges with two equivalent S(9)Tm5 trigonal bipyramids, and  an edgeedge with one S(6)Tm4 trigonal pyramid. In the tenth S site, S(10) is bonded to one Tm(5), two equivalent Tm(3), and two equivalent Tm(6) atoms to form distorted STm5 trigonal bipyramids that share corners with two equivalent S(11)Tm5 square pyramids, corners with two equivalent S(3)Tm5 square pyramids, corners with two equivalent S(9)Tm5 trigonal bipyramids, corners with four equivalent S(8)Tm4 trigonal pyramids,  an edgeedge with one S(11)Tm5 square pyramid,  an edgeedge with one S(3)Tm5 square pyramid, edges with two equivalent S(1)Tm5 trigonal bipyramids, edges with two equivalent S(10)Tm5 trigonal bipyramids, edges with two equivalent S(5)Tm5 trigonal bipyramids,  an edgeedge with one S(8)Tm4 trigonal pyramid, and edges with two equivalent S(6)Tm4 trigonal pyramids. In the eleventh S site, S(11) is bonded to one Tm(7), two equivalent Tm(2), and two equivalent Tm(3) atoms to form STm5 square pyramids that share corners with two equivalent S(3)Tm5 square pyramids, corners with two equivalent S(1)Tm5 trigonal bipyramids, corners with two equivalent S(10)Tm5 trigonal bipyramids,  an edgeedge with one S(3)Tm5 square pyramid, edges with two equivalent S(11)Tm5 square pyramids,  an edgeedge with one S(10)Tm5 trigonal bipyramid, edges with two equivalent S(9)Tm5 trigonal bipyramids, and edges with two equivalent S(6)Tm4 trigonal pyramids.