Rb3SbSe4 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 two equivalent Se(2), two equivalent Se(3), and three equivalent Se(1) atoms. In the second Rb site, Rb(2) is bonded in a 7-coordinate geometry to one Se(3), two equivalent Se(2), and four equivalent Se(1) atoms. Sb(1) is bonded in a tetrahedral geometry to one Se(2), one Se(3), and two equivalent Se(1) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Rb(2), three equivalent Rb(1), and one Sb(1) atom. In the second Se site, Se(2) is bonded in a 7-coordinate geometry to two equivalent Rb(2), four equivalent Rb(1), and one Sb(1) atom. In the third Se site, Se(3) is bonded to one Rb(2), four equivalent Rb(1), and one Sb(1) atom to form edge-sharing SeRb5Sb octahedra.
Rb3SbSe4 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 two equivalent Se(2), two equivalent Se(3), and three equivalent Se(1) atoms. There is one shorter (3.63 Å) and one longer (3.91 Å) Rb(1)-Se(2) bond length. There is one shorter (3.45 Å) and one longer (3.52 Å) Rb(1)-Se(3) bond length. There are a spread of Rb(1)-Se(1) bond distances ranging from 3.57-3.77 Å. In the second Rb site, Rb(2) is bonded in a 7-coordinate geometry to one Se(3), two equivalent Se(2), and four equivalent Se(1) atoms. The Rb(2)-Se(3) bond length is 3.38 Å. Both Rb(2)-Se(2) bond lengths are 3.62 Å. There are two shorter (3.57 Å) and two longer (3.91 Å) Rb(2)-Se(1) bond lengths. Sb(1) is bonded in a tetrahedral geometry to one Se(2), one Se(3), and two equivalent Se(1) atoms. The Sb(1)-Se(2) bond length is 2.50 Å. The Sb(1)-Se(3) bond length is 2.49 Å. Both Sb(1)-Se(1) bond lengths are 2.49 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to two equivalent Rb(2), three equivalent Rb(1), and one Sb(1) atom. In the second Se site, Se(2) is bonded in a 7-coordinate geometry to two equivalent Rb(2), four equivalent Rb(1), and one Sb(1) atom. In the third Se site, Se(3) is bonded to one Rb(2), four equivalent Rb(1), and one Sb(1) atom to form edge-sharing SeRb5Sb octahedra.