Rb2Cd3Se4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one Se(3), two equivalent Se(2), and four equivalent Se(1) atoms. In the second Rb site, Rb(2) is bonded in a 6-coordinate geometry to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing CdSe4 tetrahedra. In the second Cd site, Cd(2) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing CdSe4 tetrahedra. There are three inequivalent Se sites. In the first Se site, Se(3) is bonded in a 6-coordinate geometry to one Rb(1), two equivalent Rb(2), one Cd(2), and two equivalent Cd(1) atoms. In the second Se site, Se(1) is bonded to one Rb(2), two equivalent Rb(1), one Cd(2), and two equivalent Cd(1) atoms to form a mixture of distorted corner and edge-sharing SeRb3Cd3 octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the third Se site, Se(2) is bonded in a 7-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one Cd(2), and two equivalent Cd(1) atoms.
Rb2Cd3Se4 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one Se(3), two equivalent Se(2), and four equivalent Se(1) atoms. The Rb(1)-Se(3) bond length is 3.79 Å. There is one shorter (3.64 Å) and one longer (3.86 Å) Rb(1)-Se(2) bond length. There are two shorter (3.56 Å) and two longer (3.60 Å) Rb(1)-Se(1) bond lengths. In the second Rb site, Rb(2) is bonded in a 6-coordinate geometry to two equivalent Se(1), two equivalent Se(2), and two equivalent Se(3) atoms. Both Rb(2)-Se(1) bond lengths are 3.47 Å. Both Rb(2)-Se(2) bond lengths are 3.47 Å. Both Rb(2)-Se(3) bond lengths are 3.65 Å. There are two inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing CdSe4 tetrahedra. The Cd(1)-Se(2) bond length is 2.79 Å. The Cd(1)-Se(3) bond length is 2.70 Å. There is one shorter (2.63 Å) and one longer (2.67 Å) Cd(1)-Se(1) bond length. In the second Cd site, Cd(2) is bonded to one Se(2), one Se(3), and two equivalent Se(1) atoms to form a mixture of distorted corner and edge-sharing CdSe4 tetrahedra. The Cd(2)-Se(2) bond length is 2.68 Å. The Cd(2)-Se(3) bond length is 2.61 Å. Both Cd(2)-Se(1) bond lengths are 2.77 Å. There are three inequivalent Se sites. In the first Se site, Se(3) is bonded in a 6-coordinate geometry to one Rb(1), two equivalent Rb(2), one Cd(2), and two equivalent Cd(1) atoms. In the second Se site, Se(1) is bonded to one Rb(2), two equivalent Rb(1), one Cd(2), and two equivalent Cd(1) atoms to form a mixture of distorted corner and edge-sharing SeRb3Cd3 octahedra. The corner-sharing octahedral tilt angles range from 0-52°. In the third Se site, Se(2) is bonded in a 7-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one Cd(2), and two equivalent Cd(1) atoms.