Is Cyclopropenone Aromatic or Not?
Is cyclopropenone aromatic? Before reading on, try to anticipate the answer to that question. When most students think of aromatic, they think of simple hydrocarbons—compounds composed of hydrogen and carbon atoms only. The best known example of an aromatic hydrocarbon is the 6-sided cyclic compound benzene—C₆H₆. Benzene, if drawn according to classical structures, has alternating single and double bonds between carbon atoms. Basic Qualifications for Aromaticity A double bond consists of one sigma (σ) and one pi (π) bond. If the ring is single rather than multiple (as, for instance, for naphthalene, which is comprised of two fused rings), and if it has 4n+2 completely conjugated π electrons in a closed loop or ring, is neutral, and is flat, the structure obeys Hückel’s rule and will be aromatic. There are…