Simulating the evolution at HP of the trimer (N2)3 system, where there is a coexistence of triple intramolecular N-N bonds in N2 and secondary intermolecular N2 interactions at RP, it was found that the triple bond is destroyed at HP and single N-N bonds are formed . An equalization of intramolecular and intermolecular N-N distances in this system occurs at HP, together with an anomalous increase of the intramolecular N-N bond distance until both distances reach similar values at HP. Similarly, an equalization of intramolecular and intermolecular H-H distances occurs in elemental hydrogen at HP together with an anomalous increase of the intramolecular bond distance above 100 GPa . Simulating the ring (H2)3 system, the equalization of distances in hydrogen has been understood as due to the progressive charge transfer from intramolecular H-H bonds to intermolecular H-H bonds due to the trans influence between the primary and the secondary bonds . The pressure-induced trans influence and the corresponding anomalous increase of the bond distance of original covalent bonds in group-15 and -16 elements as well as in nitrogen and hydrogen will be further discussed in section 4 concerning the MMB nature.