Increased F-[Rg-H](+) resonance contribution provides an efficient mechanism for the Rg-H bond repolarization in the hypervalent 3c,4e-F-Rg-(HY)-Y-... complexes, where Rg is a rare gas atom. This effect which parallels the effect of rehybridization in classic 2c,2e chemical bonds, decreases the population of the sigma*(Rg-H) orbitals and increases the covalent Rg-H bond order leading to Rg-H bond contraction. The origin of this electronic reorganization can be ascribed to competition of two hyperconjugative donors for the same sigma*(Rg-H) acceptor. As donor Y approaches the H atom of an FRgH moiety, the n(Y) --> sigma*(H-Rg) interaction becomes stronger, whereas the n(F) --> sigma*(Rg-H) interaction becomes weaker in an asynchronous process. For weaker donors Y and longer (YH)-H-... distances, breaking of the Rg-F covalent bond proceeds faster than formation of the H-Y bond. As a result, both the sigma*(Rg-H) population and the Rg-H distance decrease thus accounting for the blue-shift in such H-bonded complexes. However, when Y is a moderately strong donor and/or when sigma*(Rg-H) is a very strong acceptor, a further decrease in (YH)-H-... distance leads to the formation of a sigma bond with the incoming donor (Y) in an S(N)2-like process with concomitant elimination of the fluoride moiety. As a result, the F-Rg-(HY)-Y-... systems are transformed into dissociated F(-...)Rg(...)[HY](+) complexes, and a large Rg-H elongation and red shift are observed.