Rb3SbSe3 crystallizes in the cubic P2_13 space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to six equivalent Se(1) atoms. In the second Rb site, Rb(2) is bonded to six equivalent Se(1) atoms to form distorted corner-sharing RbSe6 octahedra. The corner-sharing octahedral tilt angles are 62°. In the third Rb site, Rb(3) is bonded in a 6-coordinate geometry to six equivalent Se(1) atoms. Sb(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Se(1) atoms. Se(1) is bonded to two equivalent Rb(1), two equivalent Rb(2), two equivalent Rb(3), and one Sb(1) atom to form a mixture of distorted edge, face, and corner-sharing SeRb6Sb pentagonal bipyramids.
Rb3SbSe3 crystallizes in the cubic P2_13 space group. There are three inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 6-coordinate geometry to six equivalent Se(1) atoms. There are three shorter (3.41 Å) and three longer (3.59 Å) Rb(1)-Se(1) bond lengths. In the second Rb site, Rb(2) is bonded to six equivalent Se(1) atoms to form distorted corner-sharing RbSe6 octahedra. The corner-sharing octahedral tilt angles are 62°. There are three shorter (3.68 Å) and three longer (3.82 Å) Rb(2)-Se(1) bond lengths. In the third Rb site, Rb(3) is bonded in a 6-coordinate geometry to six equivalent Se(1) atoms. There are three shorter (3.43 Å) and three longer (3.56 Å) Rb(3)-Se(1) bond lengths. Sb(1) is bonded in a distorted trigonal non-coplanar geometry to three equivalent Se(1) atoms. All Sb(1)-Se(1) bond lengths are 2.58 Å. Se(1) is bonded to two equivalent Rb(1), two equivalent Rb(2), two equivalent Rb(3), and one Sb(1) atom to form a mixture of distorted edge, face, and corner-sharing SeRb6Sb pentagonal bipyramids.