RbC8 crystallizes in the orthorhombic Fddd space group. Rb(1) is bonded to four equivalent C(2) and eight equivalent C(1) atoms to form edge-sharing RbC12 cuboctahedra. There are two inequivalent C sites. In the first C site, C(1) is bonded in a distorted trigonal planar geometry to two equivalent Rb(1), one C(1), and two equivalent C(2) atoms. In the second C site, C(2) is bonded in a distorted trigonal planar geometry to one Rb(1), one C(2), and two equivalent C(1) atoms.
RbC8 crystallizes in the orthorhombic Fddd space group. Rb(1) is bonded to four equivalent C(2) and eight equivalent C(1) atoms to form edge-sharing RbC12 cuboctahedra. All Rb(1)-C(2) bond lengths are 3.17 Å. All Rb(1)-C(1) bond lengths are 3.15 Å. There are two inequivalent C sites. In the first C site, C(1) is bonded in a distorted trigonal planar geometry to two equivalent Rb(1), one C(1), and two equivalent C(2) atoms. The C(1)-C(1) bond length is 1.43 Å. Both C(1)-C(2) bond lengths are 1.43 Å. In the second C site, C(2) is bonded in a distorted trigonal planar geometry to one Rb(1), one C(2), and two equivalent C(1) atoms. The C(2)-C(2) bond length is 1.43 Å.