Cs3Fe2S4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 7-coordinate geometry to one S(2), two equivalent S(1), and four equivalent S(3) atoms. In the second Cs site, Cs(2) is bonded in a 6-coordinate geometry to one S(1), two equivalent S(2), and three equivalent S(3) atoms. Fe(1) is bonded to one S(1), one S(2), and two equivalent S(3) atoms to form edge-sharing FeS4 tetrahedra. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 2-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), and two equivalent Fe(1) atoms. In the second S site, S(2) is bonded in a 7-coordinate geometry to one Cs(1), four equivalent Cs(2), and two equivalent Fe(1) atoms. In the third S site, S(3) is bonded in a 7-coordinate geometry to two equivalent Cs(1), three equivalent Cs(2), and two equivalent Fe(1) atoms.
Cs3Fe2S4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 7-coordinate geometry to one S(2), two equivalent S(1), and four equivalent S(3) atoms. The Cs(1)-S(2) bond length is 3.79 Å. There is one shorter (3.77 Å) and one longer (3.90 Å) Cs(1)-S(1) bond length. There are two shorter (3.56 Å) and two longer (3.64 Å) Cs(1)-S(3) bond lengths. In the second Cs site, Cs(2) is bonded in a 6-coordinate geometry to one S(1), two equivalent S(2), and three equivalent S(3) atoms. The Cs(2)-S(1) bond length is 3.81 Å. There is one shorter (3.51 Å) and one longer (3.61 Å) Cs(2)-S(2) bond length. There are a spread of Cs(2)-S(3) bond distances ranging from 3.41-3.71 Å. Fe(1) is bonded to one S(1), one S(2), and two equivalent S(3) atoms to form edge-sharing FeS4 tetrahedra. The Fe(1)-S(1) bond length is 2.31 Å. The Fe(1)-S(2) bond length is 2.31 Å. There is one shorter (2.32 Å) and one longer (2.36 Å) Fe(1)-S(3) bond length. There are three inequivalent S sites. In the first S site, S(1) is bonded in a 2-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), and two equivalent Fe(1) atoms. In the second S site, S(2) is bonded in a 7-coordinate geometry to one Cs(1), four equivalent Cs(2), and two equivalent Fe(1) atoms. In the third S site, S(3) is bonded in a 7-coordinate geometry to two equivalent Cs(1), three equivalent Cs(2), and two equivalent Fe(1) atoms.