Cs5Nb2S4Br9 crystallizes in the orthorhombic Immm space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 10-coordinate geometry to two equivalent S(1), one Br(3), three equivalent Br(2), and four equivalent Br(1) atoms. In the second Cs site, Cs(2) is bonded to two equivalent Br(3) and four equivalent Br(2) atoms to form corner-sharing CsBr6 octahedra. The corner-sharing octahedra are not tilted. Nb(1) is bonded in a 8-coordinate geometry to four equivalent S(1), two equivalent Br(1), and two equivalent Br(2) atoms. S(1) is bonded in a 5-coordinate geometry to two equivalent Cs(1), two equivalent Nb(1), and one S(1) atom. There are three inequivalent Br sites. In the first Br site, Br(1) is bonded in a 5-coordinate geometry to four equivalent Cs(1) and one Nb(1) atom. In the second Br site, Br(2) is bonded to one Cs(2), three equivalent Cs(1), and one Nb(1) atom to form distorted BrCs4Nb trigonal bipyramids that share  a cornercorner with one Br(3)Cs6 octahedra, corners with six equivalent Br(2)Cs4Nb trigonal bipyramids, edges with two equivalent Br(3)Cs6 octahedra, and edges with two equivalent Br(2)Cs4Nb trigonal bipyramids. The corner-sharing octahedral tilt angles are 39°. In the third Br site, Br(3) is bonded to two equivalent Cs(2) and four equivalent Cs(1) atoms to form BrCs6 octahedra that share corners with two equivalent Br(3)Cs6 octahedra, corners with four equivalent Br(2)Cs4Nb trigonal bipyramids, and edges with eight equivalent Br(2)Cs4Nb trigonal bipyramids. The corner-sharing octahedra are not tilted.
Cs5Nb2S4Br9 crystallizes in the orthorhombic Immm space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 10-coordinate geometry to two equivalent S(1), one Br(3), three equivalent Br(2), and four equivalent Br(1) atoms. Both Cs(1)-S(1) bond lengths are 4.03 Å. The Cs(1)-Br(3) bond length is 3.71 Å. There is one shorter (3.61 Å) and two longer (3.92 Å) Cs(1)-Br(2) bond lengths. There are two shorter (3.77 Å) and two longer (3.87 Å) Cs(1)-Br(1) bond lengths. In the second Cs site, Cs(2) is bonded to two equivalent Br(3) and four equivalent Br(2) atoms to form corner-sharing CsBr6 octahedra. The corner-sharing octahedra are not tilted. Both Cs(2)-Br(3) bond lengths are 3.86 Å. All Cs(2)-Br(2) bond lengths are 3.59 Å. Nb(1) is bonded in a 8-coordinate geometry to four equivalent S(1), two equivalent Br(1), and two equivalent Br(2) atoms. All Nb(1)-S(1) bond lengths are 2.51 Å. Both Nb(1)-Br(1) bond lengths are 2.72 Å. Both Nb(1)-Br(2) bond lengths are 2.83 Å. S(1) is bonded in a 5-coordinate geometry to two equivalent Cs(1), two equivalent Nb(1), and one S(1) atom. The S(1)-S(1) bond length is 2.02 Å. There are three inequivalent Br sites. In the first Br site, Br(1) is bonded in a 5-coordinate geometry to four equivalent Cs(1) and one Nb(1) atom. In the second Br site, Br(2) is bonded to one Cs(2), three equivalent Cs(1), and one Nb(1) atom to form distorted BrCs4Nb trigonal bipyramids that share  a cornercorner with one Br(3)Cs6 octahedra, corners with six equivalent Br(2)Cs4Nb trigonal bipyramids, edges with two equivalent Br(3)Cs6 octahedra, and edges with two equivalent Br(2)Cs4Nb trigonal bipyramids. The corner-sharing octahedral tilt angles are 39°. In the third Br site, Br(3) is bonded to two equivalent Cs(2) and four equivalent Cs(1) atoms to form BrCs6 octahedra that share corners with two equivalent Br(3)Cs6 octahedra, corners with four equivalent Br(2)Cs4Nb trigonal bipyramids, and edges with eight equivalent Br(2)Cs4Nb trigonal bipyramids. The corner-sharing octahedra are not tilted.