Cs3GaSe3 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 6-coordinate geometry to one Se(1), two equivalent Se(3), and three equivalent Se(2) atoms. In the second Cs site, Cs(2) is bonded in a 8-coordinate geometry to one Ga(1), two equivalent Se(1), two equivalent Se(2), and three equivalent Se(3) atoms. In the third Cs site, Cs(3) is bonded in a 5-coordinate geometry to one Se(1), two equivalent Se(2), and two equivalent Se(3) atoms. Ga(1) is bonded to one Cs(2), one Se(2), one Se(3), and two equivalent Se(1) atoms to form edge-sharing GaCsSe4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to one Cs(1), one Cs(3), two equivalent Cs(2), and two equivalent Ga(1) atoms. In the second Se site, Se(2) is bonded in a 1-coordinate geometry to two equivalent Cs(2), two equivalent Cs(3), three equivalent Cs(1), and one Ga(1) atom. In the third Se site, Se(3) is bonded in a 1-coordinate geometry to two equivalent Cs(1), two equivalent Cs(3), three equivalent Cs(2), and one Ga(1) atom.
Cs3GaSe3 crystallizes in the monoclinic P2_1/c space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 6-coordinate geometry to one Se(1), two equivalent Se(3), and three equivalent Se(2) atoms. The Cs(1)-Se(1) bond length is 3.59 Å. There is one shorter (3.62 Å) and one longer (3.66 Å) Cs(1)-Se(3) bond length. There are a spread of Cs(1)-Se(2) bond distances ranging from 3.63-4.25 Å. In the second Cs site, Cs(2) is bonded in a 8-coordinate geometry to one Ga(1), two equivalent Se(1), two equivalent Se(2), and three equivalent Se(3) atoms. The Cs(2)-Ga(1) bond length is 3.73 Å. There is one shorter (3.54 Å) and one longer (3.70 Å) Cs(2)-Se(1) bond length. There is one shorter (3.69 Å) and one longer (3.87 Å) Cs(2)-Se(2) bond length. There are a spread of Cs(2)-Se(3) bond distances ranging from 3.85-4.25 Å. In the third Cs site, Cs(3) is bonded in a 5-coordinate geometry to one Se(1), two equivalent Se(2), and two equivalent Se(3) atoms. The Cs(3)-Se(1) bond length is 3.80 Å. There is one shorter (3.48 Å) and one longer (3.67 Å) Cs(3)-Se(2) bond length. There is one shorter (3.58 Å) and one longer (3.69 Å) Cs(3)-Se(3) bond length. Ga(1) is bonded to one Cs(2), one Se(2), one Se(3), and two equivalent Se(1) atoms to form edge-sharing GaCsSe4 tetrahedra. The Ga(1)-Se(2) bond length is 2.41 Å. The Ga(1)-Se(3) bond length is 2.39 Å. There is one shorter (2.47 Å) and one longer (2.51 Å) Ga(1)-Se(1) bond length. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to one Cs(1), one Cs(3), two equivalent Cs(2), and two equivalent Ga(1) atoms. In the second Se site, Se(2) is bonded in a 1-coordinate geometry to two equivalent Cs(2), two equivalent Cs(3), three equivalent Cs(1), and one Ga(1) atom. In the third Se site, Se(3) is bonded in a 1-coordinate geometry to two equivalent Cs(1), two equivalent Cs(3), three equivalent Cs(2), and one Ga(1) atom.