KIn5S8 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 8-coordinate geometry to four equivalent S(1) and four equivalent S(2) atoms. There are three inequivalent In sites. In the first In site, In(1) is bonded to one S(3), two equivalent S(4), and three equivalent S(1) atoms to form InS6 octahedra that share corners with two equivalent In(3)S6 octahedra, corners with three equivalent In(2)S4 tetrahedra, and edges with four equivalent In(1)S6 octahedra. The corner-sharing octahedral tilt angles are 48°. In the second In site, In(2) is bonded to one S(3), one S(4), and two equivalent S(2) atoms to form distorted InS4 tetrahedra that share corners with three equivalent In(1)S6 octahedra, corners with two equivalent In(2)S4 tetrahedra, and edges with two equivalent In(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 63-85°. In the third In site, In(3) is bonded to two equivalent S(2) and four equivalent S(3) atoms to form InS6 octahedra that share corners with four equivalent In(1)S6 octahedra, edges with two equivalent In(3)S6 octahedra, and edges with four equivalent In(2)S4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 3-coordinate geometry to two equivalent K(1) and three equivalent In(1) atoms. In the second S site, S(2) is bonded to two equivalent K(1), one In(3), and two equivalent In(2) atoms to form distorted SK2In3 trigonal bipyramids that share corners with three equivalent S(2)K2In3 trigonal bipyramids, corners with two equivalent S(3)In4 trigonal pyramids, edges with three equivalent S(2)K2In3 trigonal bipyramids, and edges with two equivalent S(3)In4 trigonal pyramids. In the third S site, S(3) is bonded to one In(1), one In(2), and two equivalent In(3) atoms to form SIn4 trigonal pyramids that share corners with two equivalent S(2)K2In3 trigonal bipyramids, corners with four equivalent S(3)In4 trigonal pyramids, edges with two equivalent S(2)K2In3 trigonal bipyramids, and  an edgeedge with one S(3)In4 trigonal pyramid. In the fourth S site, S(4) is bonded in a distorted trigonal non-coplanar geometry to one In(2) and two equivalent In(1) atoms.
KIn5S8 crystallizes in the monoclinic C2/m space group. K(1) is bonded in a 8-coordinate geometry to four equivalent S(1) and four equivalent S(2) atoms. All K(1)-S(1) bond lengths are 3.74 Å. All K(1)-S(2) bond lengths are 3.30 Å. There are three inequivalent In sites. In the first In site, In(1) is bonded to one S(3), two equivalent S(4), and three equivalent S(1) atoms to form InS6 octahedra that share corners with two equivalent In(3)S6 octahedra, corners with three equivalent In(2)S4 tetrahedra, and edges with four equivalent In(1)S6 octahedra. The corner-sharing octahedral tilt angles are 48°. The In(1)-S(3) bond length is 2.76 Å. Both In(1)-S(4) bond lengths are 2.70 Å. There is one shorter (2.58 Å) and two longer (2.61 Å) In(1)-S(1) bond lengths. In the second In site, In(2) is bonded to one S(3), one S(4), and two equivalent S(2) atoms to form distorted InS4 tetrahedra that share corners with three equivalent In(1)S6 octahedra, corners with two equivalent In(2)S4 tetrahedra, and edges with two equivalent In(3)S6 octahedra. The corner-sharing octahedral tilt angles range from 63-85°. The In(2)-S(3) bond length is 2.52 Å. The In(2)-S(4) bond length is 2.43 Å. Both In(2)-S(2) bond lengths are 2.54 Å. In the third In site, In(3) is bonded to two equivalent S(2) and four equivalent S(3) atoms to form InS6 octahedra that share corners with four equivalent In(1)S6 octahedra, edges with two equivalent In(3)S6 octahedra, and edges with four equivalent In(2)S4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. Both In(3)-S(2) bond lengths are 2.64 Å. All In(3)-S(3) bond lengths are 2.63 Å. There are four inequivalent S sites. In the first S site, S(1) is bonded in a 3-coordinate geometry to two equivalent K(1) and three equivalent In(1) atoms. In the second S site, S(2) is bonded to two equivalent K(1), one In(3), and two equivalent In(2) atoms to form distorted SK2In3 trigonal bipyramids that share corners with three equivalent S(2)K2In3 trigonal bipyramids, corners with two equivalent S(3)In4 trigonal pyramids, edges with three equivalent S(2)K2In3 trigonal bipyramids, and edges with two equivalent S(3)In4 trigonal pyramids. In the third S site, S(3) is bonded to one In(1), one In(2), and two equivalent In(3) atoms to form SIn4 trigonal pyramids that share corners with two equivalent S(2)K2In3 trigonal bipyramids, corners with four equivalent S(3)In4 trigonal pyramids, edges with two equivalent S(2)K2In3 trigonal bipyramids, and  an edgeedge with one S(3)In4 trigonal pyramid. In the fourth S site, S(4) is bonded in a distorted trigonal non-coplanar geometry to one In(2) and two equivalent In(1) atoms.