Interestingly, the octet rule seems to be violated in the hypercoordinated units with EDMBs for group-16 elements, e.g. the cubic and rhombohedral A(0,1,3) units of α-Po and β-Po. In this case, in addition to the six p-type electrons of the three EDMBs around each central A atom (three coming from the central atom), one has to count the three additional electrons of the A atom (two s-type electrons corresponding to the LEP plus the extra p electron in chalcogens compared to pnictogens). These extra electrons are distributed: i) among the six lobes of the cubic A(0,1,3) unit (Fig. ), as previously noted for α-Po, or ii) in the toroidal pink halo (monosynaptic basin) of the rhombohedral A(0,1,3) unit (Fig. ) typical of β-Po. Therefore, a total number of nine electrons seems to be around each hypercoordinated EDMB unit for chalcogens, thus violating the octet rule. Curiously, the prevalence of the cubic vs. the rhombohedral units in AF6E molecules (A is the central atom, F is the ligand atom and E is the LEP) with ERMBs, such as XeF6, has been already studied . It has been concluded that AF6E molecules with both the cubic Oh symmetry, like that of the cubic unit of Fig. , or the C3v symmetry, like that of the rhombohedral unit of Fig. , are very close in energy. The predominance of one geometry over the other seems to be related to a very fine balance between ligand-ligand repulsions and the energy gained by the expansion of the two nonbonding electrons of the LEP in the valence shell that mainly depends on the atomic radii ratio between the central atom and the ligands.