A paradigmatic example of MMB formation occurs in Po at RP. Po is the only chalcogen that shows octahedral coordination at RP, either in the cubic Ah structure (α-Po) at RP and room temperature or in the rhombohedral Ai phase (β-Po) at RP and high temperature. Our calculations show that β-Po at RP features a quasi-cubic arrangement of Po atoms, i.e. β-Po shows a very small distortion with respect to α-Po since all six bond distances are equal in both phases and only a small deviation of the rhombohedral bond angle from 90° occurs in β-Po at RP. This deviation disappears at HP, thus leading to a PT to α-Po below 2 GPa (see Fig. in ESI). As regards the vibrational properties, both phases of Po have only acoustic phonons and the presence of MMBs in Po is here only evidenced by the high (negligible) values of Z* (∇ 2 ρ) at all calculated pressures (see Fig. ). Notably, the bonds in α-Po and β-Po correspond to the cubic and rhombohedral hypercoordinated multicenter units of Fig. , respectively, already mentioned as possible HP phases of the rest of pnictogens and chalcogens.