According to Huckel's rule, which of the following cyclic, planar, and fully conjugated species is s — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

Anti-aromatic compounds are cyclic, planar, fully conjugated systems possessing $4n$ $\pi$ -electrons. The cyclopropenyl anion has 2 $\pi$ -electrons from the double bond and 2 from the lone pair, totaling 4 $\pi$ -electrons (where $n=1$), making it highly unstable and anti-aromatic.