A similar lecture on the ELF isosurfaces can be done for chalcogens. Each Se and Te atom in the A8 structure at RP (stage 2) is characterized by two ELF attractors or lobes that are already aligned in the directions of two of the four secondary bonds, i.e. they form an angle of nearly 180 with the nearest covalent bond (Fig. ). These features agree with previous calculations , and are typical of p-type LEPs. In other words, there is a p-type LEP distributed along two (of the four) secondary bonds of each atom of Se and Te at RP and no LEP lobe pointing along the other two secondary bonds of the same atom. As pressure increases, the two LEP lobes become distorted so that they spread over the four secondary bonds. Finally, upon the A8-to-Ai PT at Pt (stage 3), an ELF attractor with a toroidal shape is observed around each atom (Fig. ). This toroidal shape of the ELF is also found in β-Po at RP. Therefore, we conclude that a toroidal ELF attractor is characteristic of MMBs in the hypercoordinated multicenter unit with rhombohedral symmetry shown in Fig. .