(CeO)4Ga2S5 crystallizes in the triclinic P1 space group. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 4-coordinate geometry to one S(5), two equivalent S(3), two equivalent S(4), one O(3), one O(4), and two equivalent O(1) atoms. In the second Ce site, Ce(2) is bonded in a 4-coordinate geometry to two equivalent S(3), two equivalent S(4), one O(3), one O(4), and two equivalent O(2) atoms. In the third Ce site, Ce(3) is bonded in a 4-coordinate geometry to one S(5), two equivalent S(1), two equivalent S(2), one O(1), one O(2), and two equivalent O(3) atoms. In the fourth Ce site, Ce(4) is bonded in a 4-coordinate geometry to two equivalent S(1), two equivalent S(2), one O(1), one O(2), and two equivalent O(4) atoms. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one S(2), one S(3), and two equivalent S(5) atoms to form corner-sharing GaS4 tetrahedra. In the second Ga site, Ga(2) is bonded in a 3-coordinate geometry to one S(1), one S(4), and one S(5) atom. There are five inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Ce(3), two equivalent Ce(4), and one Ga(2) atom. In the second S site, S(2) is bonded in a 5-coordinate geometry to two equivalent Ce(3), two equivalent Ce(4), and one Ga(1) atom. In the third S site, S(3) is bonded in a 5-coordinate geometry to two equivalent Ce(1), two equivalent Ce(2), and one Ga(1) atom. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to two equivalent Ce(1), two equivalent Ce(2), and one Ga(2) atom. In the fifth S site, S(5) is bonded to one Ce(1), one Ce(3), one Ga(2), and two equivalent Ga(1) atoms to form distorted SCe2Ga3 trigonal bipyramids that share  a cornercorner with one O(2)Ce4 tetrahedra,  a cornercorner with one O(4)Ce4 tetrahedra, corners with three equivalent O(1)Ce4 tetrahedra, corners with three equivalent O(3)Ce4 tetrahedra, and corners with two equivalent S(5)Ce2Ga3 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ce(3), one Ce(4), and two equivalent Ce(1) atoms to form OCe4 tetrahedra that share corners with two equivalent O(1)Ce4 tetrahedra, corners with two equivalent O(2)Ce4 tetrahedra, corners with three equivalent S(5)Ce2Ga3 trigonal bipyramids, edges with two equivalent O(3)Ce4 tetrahedra, and edges with two equivalent O(4)Ce4 tetrahedra. In the second O site, O(2) is bonded to one Ce(3), one Ce(4), and two equivalent Ce(2) atoms to form OCe4 tetrahedra that share corners with two equivalent O(1)Ce4 tetrahedra, corners with two equivalent O(2)Ce4 tetrahedra,  a cornercorner with one S(5)Ce2Ga3 trigonal bipyramid, edges with two equivalent O(3)Ce4 tetrahedra, and edges with two equivalent O(4)Ce4 tetrahedra. In the third O site, O(3) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with two equivalent O(3)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra, corners with three equivalent S(5)Ce2Ga3 trigonal bipyramids, edges with two equivalent O(1)Ce4 tetrahedra, and edges with two equivalent O(2)Ce4 tetrahedra. In the fourth O site, O(4) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(4) atoms to form OCe4 tetrahedra that share corners with two equivalent O(3)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra,  a cornercorner with one S(5)Ce2Ga3 trigonal bipyramid, edges with two equivalent O(1)Ce4 tetrahedra, and edges with two equivalent O(2)Ce4 tetrahedra.
(CeO)4Ga2S5 crystallizes in the triclinic P1 space group. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 4-coordinate geometry to one S(5), two equivalent S(3), two equivalent S(4), one O(3), one O(4), and two equivalent O(1) atoms. The Ce(1)-S(5) bond length is 3.28 Å. There is one shorter (3.13 Å) and one longer (3.14 Å) Ce(1)-S(3) bond length. Both Ce(1)-S(4) bond lengths are 3.07 Å. The Ce(1)-O(3) bond length is 2.39 Å. The Ce(1)-O(4) bond length is 2.36 Å. There is one shorter (2.32 Å) and one longer (2.33 Å) Ce(1)-O(1) bond length. In the second Ce site, Ce(2) is bonded in a 4-coordinate geometry to two equivalent S(3), two equivalent S(4), one O(3), one O(4), and two equivalent O(2) atoms. Both Ce(2)-S(3) bond lengths are 3.02 Å. There is one shorter (2.98 Å) and one longer (3.01 Å) Ce(2)-S(4) bond length. The Ce(2)-O(3) bond length is 2.36 Å. The Ce(2)-O(4) bond length is 2.30 Å. There is one shorter (2.33 Å) and one longer (2.34 Å) Ce(2)-O(2) bond length. In the third Ce site, Ce(3) is bonded in a 4-coordinate geometry to one S(5), two equivalent S(1), two equivalent S(2), one O(1), one O(2), and two equivalent O(3) atoms. The Ce(3)-S(5) bond length is 3.37 Å. Both Ce(3)-S(1) bond lengths are 3.05 Å. There is one shorter (3.15 Å) and one longer (3.16 Å) Ce(3)-S(2) bond length. The Ce(3)-O(1) bond length is 2.35 Å. The Ce(3)-O(2) bond length is 2.34 Å. There is one shorter (2.33 Å) and one longer (2.34 Å) Ce(3)-O(3) bond length. In the fourth Ce site, Ce(4) is bonded in a 4-coordinate geometry to two equivalent S(1), two equivalent S(2), one O(1), one O(2), and two equivalent O(4) atoms. There is one shorter (2.96 Å) and one longer (2.99 Å) Ce(4)-S(1) bond length. There is one shorter (3.02 Å) and one longer (3.03 Å) Ce(4)-S(2) bond length. The Ce(4)-O(1) bond length is 2.34 Å. The Ce(4)-O(2) bond length is 2.38 Å. Both Ce(4)-O(4) bond lengths are 2.33 Å. There are two inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one S(2), one S(3), and two equivalent S(5) atoms to form corner-sharing GaS4 tetrahedra. The Ga(1)-S(2) bond length is 2.25 Å. The Ga(1)-S(3) bond length is 2.25 Å. There is one shorter (2.33 Å) and one longer (2.35 Å) Ga(1)-S(5) bond length. In the second Ga site, Ga(2) is bonded in a 3-coordinate geometry to one S(1), one S(4), and one S(5) atom. The Ga(2)-S(1) bond length is 2.58 Å. The Ga(2)-S(4) bond length is 2.55 Å. The Ga(2)-S(5) bond length is 2.64 Å. There are five inequivalent S sites. In the first S site, S(1) is bonded in a 5-coordinate geometry to two equivalent Ce(3), two equivalent Ce(4), and one Ga(2) atom. In the second S site, S(2) is bonded in a 5-coordinate geometry to two equivalent Ce(3), two equivalent Ce(4), and one Ga(1) atom. In the third S site, S(3) is bonded in a 5-coordinate geometry to two equivalent Ce(1), two equivalent Ce(2), and one Ga(1) atom. In the fourth S site, S(4) is bonded in a 5-coordinate geometry to two equivalent Ce(1), two equivalent Ce(2), and one Ga(2) atom. In the fifth S site, S(5) is bonded to one Ce(1), one Ce(3), one Ga(2), and two equivalent Ga(1) atoms to form distorted SCe2Ga3 trigonal bipyramids that share  a cornercorner with one O(2)Ce4 tetrahedra,  a cornercorner with one O(4)Ce4 tetrahedra, corners with three equivalent O(1)Ce4 tetrahedra, corners with three equivalent O(3)Ce4 tetrahedra, and corners with two equivalent S(5)Ce2Ga3 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Ce(3), one Ce(4), and two equivalent Ce(1) atoms to form OCe4 tetrahedra that share corners with two equivalent O(1)Ce4 tetrahedra, corners with two equivalent O(2)Ce4 tetrahedra, corners with three equivalent S(5)Ce2Ga3 trigonal bipyramids, edges with two equivalent O(3)Ce4 tetrahedra, and edges with two equivalent O(4)Ce4 tetrahedra. In the second O site, O(2) is bonded to one Ce(3), one Ce(4), and two equivalent Ce(2) atoms to form OCe4 tetrahedra that share corners with two equivalent O(1)Ce4 tetrahedra, corners with two equivalent O(2)Ce4 tetrahedra,  a cornercorner with one S(5)Ce2Ga3 trigonal bipyramid, edges with two equivalent O(3)Ce4 tetrahedra, and edges with two equivalent O(4)Ce4 tetrahedra. In the third O site, O(3) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form OCe4 tetrahedra that share corners with two equivalent O(3)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra, corners with three equivalent S(5)Ce2Ga3 trigonal bipyramids, edges with two equivalent O(1)Ce4 tetrahedra, and edges with two equivalent O(2)Ce4 tetrahedra. In the fourth O site, O(4) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(4) atoms to form OCe4 tetrahedra that share corners with two equivalent O(3)Ce4 tetrahedra, corners with two equivalent O(4)Ce4 tetrahedra,  a cornercorner with one S(5)Ce2Ga3 trigonal bipyramid, edges with two equivalent O(1)Ce4 tetrahedra, and edges with two equivalent O(2)Ce4 tetrahedra.