Cs5Ga3Se7 crystallizes in the monoclinic C2/m space group. There are four inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 7-coordinate geometry to one Se(3), two equivalent Se(1), two equivalent Se(2), and two equivalent Se(5) atoms. In the second Cs site, Cs(2) is bonded in a 6-coordinate geometry to two equivalent Se(1), two equivalent Se(4), and two equivalent Se(5) atoms. In the third Cs site, Cs(3) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(5) atoms. In the fourth Cs site, Cs(4) is bonded in a 5-coordinate geometry to one Se(4) and four equivalent Se(5) atoms. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one Se(2), one Se(4), and two equivalent Se(1) atoms to form edge-sharing GaSe4 tetrahedra. In the second Ga site, Ga(2) is bonded to two equivalent Se(1) and two equivalent Se(3) atoms to form edge-sharing GaSe4 tetrahedra. In the third Ga site, Ga(3) is bonded to one Se(2), one Se(4), and two equivalent Se(5) atoms to form edge-sharing GaSe4 tetrahedra. There are five inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to one Cs(2), one Cs(3), two equivalent Cs(1), one Ga(1), and one Ga(2) atom. In the second Se site, Se(2) is bonded in a distorted L-shaped geometry to two equivalent Cs(3), four equivalent Cs(1), one Ga(1), and one Ga(3) atom. In the third Se site, Se(3) is bonded in a 2-coordinate geometry to two equivalent Cs(1), two equivalent Cs(3), and two equivalent Ga(2) atoms. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to one Cs(4), two equivalent Cs(2), one Ga(1), and one Ga(3) atom. In the fifth Se site, Se(5) is bonded to one Cs(2), one Cs(3), two equivalent Cs(1), two equivalent Cs(4), and one Ga(3) atom to form a mixture of distorted edge, face, and corner-sharing SeCs6Ga pentagonal bipyramids.
Cs5Ga3Se7 crystallizes in the monoclinic C2/m space group. There are four inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 7-coordinate geometry to one Se(3), two equivalent Se(1), two equivalent Se(2), and two equivalent Se(5) atoms. The Cs(1)-Se(3) bond length is 3.97 Å. There is one shorter (3.75 Å) and one longer (3.79 Å) Cs(1)-Se(1) bond length. There is one shorter (4.02 Å) and one longer (4.13 Å) Cs(1)-Se(2) bond length. There is one shorter (3.51 Å) and one longer (3.76 Å) Cs(1)-Se(5) bond length. In the second Cs site, Cs(2) is bonded in a 6-coordinate geometry to two equivalent Se(1), two equivalent Se(4), and two equivalent Se(5) atoms. Both Cs(2)-Se(1) bond lengths are 3.69 Å. Both Cs(2)-Se(4) bond lengths are 3.81 Å. Both Cs(2)-Se(5) bond lengths are 3.80 Å. In the third Cs site, Cs(3) is bonded in a 8-coordinate geometry to two equivalent Se(1), two equivalent Se(2), two equivalent Se(3), and two equivalent Se(5) atoms. Both Cs(3)-Se(1) bond lengths are 3.87 Å. Both Cs(3)-Se(2) bond lengths are 4.10 Å. Both Cs(3)-Se(3) bond lengths are 4.10 Å. Both Cs(3)-Se(5) bond lengths are 3.47 Å. In the fourth Cs site, Cs(4) is bonded in a 5-coordinate geometry to one Se(4) and four equivalent Se(5) atoms. The Cs(4)-Se(4) bond length is 3.57 Å. There are two shorter (3.61 Å) and two longer (3.65 Å) Cs(4)-Se(5) bond lengths. There are three inequivalent Ga sites. In the first Ga site, Ga(1) is bonded to one Se(2), one Se(4), and two equivalent Se(1) atoms to form edge-sharing GaSe4 tetrahedra. The Ga(1)-Se(2) bond length is 2.40 Å. The Ga(1)-Se(4) bond length is 2.40 Å. Both Ga(1)-Se(1) bond lengths are 2.45 Å. In the second Ga site, Ga(2) is bonded to two equivalent Se(1) and two equivalent Se(3) atoms to form edge-sharing GaSe4 tetrahedra. Both Ga(2)-Se(1) bond lengths are 2.43 Å. Both Ga(2)-Se(3) bond lengths are 2.43 Å. In the third Ga site, Ga(3) is bonded to one Se(2), one Se(4), and two equivalent Se(5) atoms to form edge-sharing GaSe4 tetrahedra. The Ga(3)-Se(2) bond length is 2.50 Å. The Ga(3)-Se(4) bond length is 2.51 Å. Both Ga(3)-Se(5) bond lengths are 2.37 Å. There are five inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to one Cs(2), one Cs(3), two equivalent Cs(1), one Ga(1), and one Ga(2) atom. In the second Se site, Se(2) is bonded in a distorted L-shaped geometry to two equivalent Cs(3), four equivalent Cs(1), one Ga(1), and one Ga(3) atom. In the third Se site, Se(3) is bonded in a 2-coordinate geometry to two equivalent Cs(1), two equivalent Cs(3), and two equivalent Ga(2) atoms. In the fourth Se site, Se(4) is bonded in a 5-coordinate geometry to one Cs(4), two equivalent Cs(2), one Ga(1), and one Ga(3) atom. In the fifth Se site, Se(5) is bonded to one Cs(2), one Cs(3), two equivalent Cs(1), two equivalent Cs(4), and one Ga(3) atom to form a mixture of distorted edge, face, and corner-sharing SeCs6Ga pentagonal bipyramids.