AbstractThe electron transfer process is systematically examined in K0.33MoO3 semiconductor red bronze and in K0.30MoO3 metallic blue bronze as a direct consequence of cation‐anion orbital overlaps. The critical interatomic distance below which the overlap occurs is established at about 0.196 nm. In K0.33MoO3, it is shown that closed localized molecular‐type orbitals correlate the rigid units which characterize the MoO3 layers. In K0.30MoO3, the paths for collective electrons are three quasi‐one dimensional Mo–O chains, with occurrence of transverse correlations between the two among them which are equivalent. The third chain connects two staggered rigid‐unit columns. The coupling of the metal–semiconductor transition with the lattice modulation is investigated in correlation with low temperature structural slight rearrangements and atomic displacements. It is shown that a part of collective electrons can condense in collective localized orbitals which close in between two equivalent chains with the modulation periodicity. The extension of transverse correlations towards the third inequivalent chain is discussed in relation with orbital overlaps and with the two‐band states model. Finally a microstructural model is proposed, which can describe in terms of interface modulation the conduction electron modulation and its incommensurability.