Cs2FeGaS4 crystallizes in the monoclinic C2 space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 8-coordinate geometry to four equivalent S(1) and four equivalent S(2) atoms. In the second Cs site, Cs(2) is bonded in a 8-coordinate geometry to four equivalent S(1) and four equivalent S(2) atoms. Fe(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form FeS4 tetrahedra that share edges with two equivalent Ga(1)S4 tetrahedra. Ga(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form GaS4 tetrahedra that share edges with two equivalent Fe(1)S4 tetrahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), one Fe(1), and one Ga(1) atom. In the second S site, S(2) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), one Fe(1), and one Ga(1) atom.
Cs2FeGaS4 crystallizes in the monoclinic C2 space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 8-coordinate geometry to four equivalent S(1) and four equivalent S(2) atoms. There are two shorter (3.70 Å) and two longer (3.79 Å) Cs(1)-S(1) bond lengths. There are two shorter (3.69 Å) and two longer (3.70 Å) Cs(1)-S(2) bond lengths. In the second Cs site, Cs(2) is bonded in a 8-coordinate geometry to four equivalent S(1) and four equivalent S(2) atoms. There are two shorter (3.69 Å) and two longer (3.70 Å) Cs(2)-S(1) bond lengths. There are two shorter (3.70 Å) and two longer (3.79 Å) Cs(2)-S(2) bond lengths. Fe(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form FeS4 tetrahedra that share edges with two equivalent Ga(1)S4 tetrahedra. Both Fe(1)-S(1) bond lengths are 2.29 Å. Both Fe(1)-S(2) bond lengths are 2.30 Å. Ga(1) is bonded to two equivalent S(1) and two equivalent S(2) atoms to form GaS4 tetrahedra that share edges with two equivalent Fe(1)S4 tetrahedra. Both Ga(1)-S(1) bond lengths are 2.30 Å. Both Ga(1)-S(2) bond lengths are 2.30 Å. There are two inequivalent S sites. In the first S site, S(1) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), one Fe(1), and one Ga(1) atom. In the second S site, S(2) is bonded in a 6-coordinate geometry to two equivalent Cs(1), two equivalent Cs(2), one Fe(1), and one Ga(1) atom.