RbSb2 crystallizes in the monoclinic C2/m space group. Rb(1) is bonded in a 8-coordinate geometry to three equivalent Sb(2) and five equivalent Sb(1) atoms. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to five equivalent Rb(1) and two equivalent Sb(2) atoms to form distorted SbRb5Sb2 pentagonal bipyramids that share corners with four equivalent Sb(1)Rb5Sb2 pentagonal bipyramids, corners with nine equivalent Sb(2)Rb3Sb3 pentagonal pyramids, edges with four equivalent Sb(1)Rb5Sb2 pentagonal bipyramids, edges with four equivalent Sb(2)Rb3Sb3 pentagonal pyramids, and faces with three equivalent Sb(1)Rb5Sb2 pentagonal bipyramids. In the second Sb site, Sb(2) is bonded to three equivalent Rb(1), one Sb(2), and two equivalent Sb(1) atoms to form distorted SbRb3Sb3 pentagonal pyramids that share corners with nine equivalent Sb(1)Rb5Sb2 pentagonal bipyramids, edges with four equivalent Sb(1)Rb5Sb2 pentagonal bipyramids, and edges with four equivalent Sb(2)Rb3Sb3 pentagonal pyramids.
RbSb2 crystallizes in the monoclinic C2/m space group. Rb(1) is bonded in a 8-coordinate geometry to three equivalent Sb(2) and five equivalent Sb(1) atoms. There are two shorter (3.95 Å) and one longer (3.99 Å) Rb(1)-Sb(2) bond length. There are three shorter (3.85 Å) and two longer (3.91 Å) Rb(1)-Sb(1) bond lengths. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to five equivalent Rb(1) and two equivalent Sb(2) atoms to form distorted SbRb5Sb2 pentagonal bipyramids that share corners with four equivalent Sb(1)Rb5Sb2 pentagonal bipyramids, corners with nine equivalent Sb(2)Rb3Sb3 pentagonal pyramids, edges with four equivalent Sb(1)Rb5Sb2 pentagonal bipyramids, edges with four equivalent Sb(2)Rb3Sb3 pentagonal pyramids, and faces with three equivalent Sb(1)Rb5Sb2 pentagonal bipyramids. Both Sb(1)-Sb(2) bond lengths are 2.85 Å. In the second Sb site, Sb(2) is bonded to three equivalent Rb(1), one Sb(2), and two equivalent Sb(1) atoms to form distorted SbRb3Sb3 pentagonal pyramids that share corners with nine equivalent Sb(1)Rb5Sb2 pentagonal bipyramids, edges with four equivalent Sb(1)Rb5Sb2 pentagonal bipyramids, and edges with four equivalent Sb(2)Rb3Sb3 pentagonal pyramids. The Sb(2)-Sb(2) bond length is 2.86 Å.