Regarding EDMBs, it seems that the octet rule seems to be satisfied in molecules and the same is expected in solids. Taking into account the above considerations, eight electrons seem to surround each A atom in hypercoordinated units with only one EDMB (1D geometry), such as in the A(0,3,1), A(1,2,1), A(2,1,1), and A(3,0,1) units of Fig. . The same occurs for the units with two EDMBs (2D geometry), the A(0,2,2), A(1,1,2), and A(2,0,2) units of Fig. , and for the units with three EDMBs (3D geometry), such as the cubic A(0,1,3) units of Fig. . A clear example of the validity of the octet rule in the A(0,1,3) unit is the Ah phase of group-15 elements. Group-15 elements have two s-type and three p-type electrons. In the Ah phase, the s-type electrons form part of the inactive LEP and are distributed into six lobes, as shown in the cubic A(0,1,3) unit of Fig. , while the p-type electrons participate in the three mutually perpendicular EDMBs. Therefore, the central A atom of the A(0,1,3) units has valence eight electrons, thus satisfying the octet rule. This result is contrary to the previous assumption that hypercoordinated units in MMBs led to a violation of the octet rule .