Cs3Sb5S9 crystallizes in the monoclinic C2/m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 8-coordinate geometry to two equivalent S(1), two equivalent S(3), two equivalent S(4), and two equivalent S(5) atoms. In the second Cs site, Cs(2) is bonded in a 9-coordinate geometry to one S(6), two equivalent S(2), three equivalent S(3), and three equivalent S(4) atoms. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent S(3), two equivalent S(5), and two equivalent S(6) atoms to form a mixture of corner and edge-sharing SbS6 octahedra. The corner-sharing octahedral tilt angles are 15°. In the second Sb site, Sb(2) is bonded to two equivalent S(1), two equivalent S(4), and two equivalent S(6) atoms to form a mixture of corner and edge-sharing SbS6 octahedra. The corner-sharing octahedral tilt angles are 15°. In the third Sb site, Sb(3) is bonded in a 3-coordinate geometry to one S(2), one S(3), and one S(4) atom. In the fourth Sb site, Sb(4) is bonded in a rectangular see-saw-like geometry to one S(1), one S(5), and two equivalent S(6) atoms. There are six inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Cs(1), one Sb(4), and two equivalent Sb(2) atoms. In the second S site, S(2) is bonded to four equivalent Cs(2) and two equivalent Sb(3) atoms to form distorted edge-sharing SCs4Sb2 octahedra. In the third S site, S(3) is bonded in a 6-coordinate geometry to one Cs(1), three equivalent Cs(2), one Sb(1), and one Sb(3) atom. In the fourth S site, S(4) is bonded in a 6-coordinate geometry to one Cs(1), three equivalent Cs(2), one Sb(2), and one Sb(3) atom. In the fifth S site, S(5) is bonded in a 5-coordinate geometry to two equivalent Cs(1), one Sb(4), and two equivalent Sb(1) atoms. In the sixth S site, S(6) is bonded in a 4-coordinate geometry to one Cs(2), one Sb(1), one Sb(2), and one Sb(4) atom.
Cs3Sb5S9 crystallizes in the monoclinic C2/m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 8-coordinate geometry to two equivalent S(1), two equivalent S(3), two equivalent S(4), and two equivalent S(5) atoms. Both Cs(1)-S(1) bond lengths are 3.99 Å. Both Cs(1)-S(3) bond lengths are 3.57 Å. Both Cs(1)-S(4) bond lengths are 3.71 Å. Both Cs(1)-S(5) bond lengths are 4.02 Å. In the second Cs site, Cs(2) is bonded in a 9-coordinate geometry to one S(6), two equivalent S(2), three equivalent S(3), and three equivalent S(4) atoms. The Cs(2)-S(6) bond length is 3.59 Å. There is one shorter (3.63 Å) and one longer (3.65 Å) Cs(2)-S(2) bond length. There are a spread of Cs(2)-S(3) bond distances ranging from 3.61-3.93 Å. There are a spread of Cs(2)-S(4) bond distances ranging from 3.65-3.91 Å. There are four inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent S(3), two equivalent S(5), and two equivalent S(6) atoms to form a mixture of corner and edge-sharing SbS6 octahedra. The corner-sharing octahedral tilt angles are 15°. Both Sb(1)-S(3) bond lengths are 2.97 Å. Both Sb(1)-S(5) bond lengths are 2.61 Å. Both Sb(1)-S(6) bond lengths are 2.85 Å. In the second Sb site, Sb(2) is bonded to two equivalent S(1), two equivalent S(4), and two equivalent S(6) atoms to form a mixture of corner and edge-sharing SbS6 octahedra. The corner-sharing octahedral tilt angles are 15°. Both Sb(2)-S(1) bond lengths are 2.78 Å. Both Sb(2)-S(4) bond lengths are 2.77 Å. Both Sb(2)-S(6) bond lengths are 2.81 Å. In the third Sb site, Sb(3) is bonded in a 3-coordinate geometry to one S(2), one S(3), and one S(4) atom. The Sb(3)-S(2) bond length is 2.53 Å. The Sb(3)-S(3) bond length is 2.41 Å. The Sb(3)-S(4) bond length is 2.45 Å. In the fourth Sb site, Sb(4) is bonded in a rectangular see-saw-like geometry to one S(1), one S(5), and two equivalent S(6) atoms. The Sb(4)-S(1) bond length is 2.60 Å. The Sb(4)-S(5) bond length is 2.98 Å. Both Sb(4)-S(6) bond lengths are 2.49 Å. There are six inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Cs(1), one Sb(4), and two equivalent Sb(2) atoms. In the second S site, S(2) is bonded to four equivalent Cs(2) and two equivalent Sb(3) atoms to form distorted edge-sharing SCs4Sb2 octahedra. In the third S site, S(3) is bonded in a 6-coordinate geometry to one Cs(1), three equivalent Cs(2), one Sb(1), and one Sb(3) atom. In the fourth S site, S(4) is bonded in a 6-coordinate geometry to one Cs(1), three equivalent Cs(2), one Sb(2), and one Sb(3) atom. In the fifth S site, S(5) is bonded in a 5-coordinate geometry to two equivalent Cs(1), one Sb(4), and two equivalent Sb(1) atoms. In the sixth S site, S(6) is bonded in a 4-coordinate geometry to one Cs(2), one Sb(1), one Sb(2), and one Sb(4) atom.