Which of the following charged cyclic species intrinsically satisfy Huckel's rule and behave as high — Hydrocarbons Chemistry Question

💡 Solution & Explanation

(A) The cyclopropenyl cation contains 2 $\pi$ electrons ($4n+2$ where $n=0$). (B) The cyclopentadienyl anion contains two double bonds plus a lone pair in a $p$ -orbital, totaling 6 $\pi$ electrons ($n=1$). (C) The cycloheptatrienyl (tropylium) cation has three double bonds and an empty $p$ -orbital, totaling 6 $\pi$ electrons ($n=1$). All three are planar, cyclic, fully conjugated, and satisfy Huckel's rule, making them aromatic. (D) The cyclopentadienyl cation has 4 $\pi$ electrons, making it anti-aromatic.