The 'increased-valence' formulae take account of the effect of resonance on nearest-neigh- bour bond-order in a manner which is identical to that which pertains when the valence structure A-B for a 1-electron bond is ysed to sumparize resonance between the structures A B and A B. ...
The significance of 'long-bond' (or spin-paired diradical) structures for the electronic mechanism of 1,3-dipolar cycloaddition reactions is discussed and 'increased-valence' descriptions of the electronic structure of each molecule are presented. Some comments on the utility of 'increased-valence'...