Benzyl cation is the phenyl substituted methyl cation. Benzyl cation is very stable. The high stability of benzyl cation is explained by the efficient resonance stabilization of the exocyclic methylene group. Draw all important resonance forms. Given the information that the exocyclic C-C bond is 137.2 pm long, how important do you think the "phenyl methyl cation" resonance form is as compared to the resonance forms that contain an exocyclic double bond?