The prefix xn is proposed for the classification of valence‐bond isomers of aromatic systems, where n is the change in the number of rings or in the number of π‐bonds on isomerization. Representatives of the x1‐series are Dewar benzene and 9, 10‐dihydronaphthalene. Benzvalene and prismane belong to the x2 and x3 series, respectively. Various derivatives of such valence‐bond isomers have recently become known.
No takes yet. Share an insight, caveat, or question.
Eugene E. Van Tamelen (1965) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: