Which aromatic compound has two double bonds | vedclass

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(B) For a compound to be aromatic,it must follow $H$ückel's rule,which states that the compound must have $(4n + 2) \pi$ electrons,where $n$ is an int

Vedclass · Accepted Answer

Cyclopentadienyl anion

Vedclass · Answer

(B) For a compound to be aromatic,it must follow $H$ückel's rule,which states that the compound must have $(4n + 2) \pi$ electrons,where $n$ is an integer $(0, 1, 2, \dots)$.In a five-membered ring,to achieve aromaticity,the system must have $6 \pi$ electrons $(n=1)$.Cyclopentadiene has $4 \pi$ electrons and is non-aromatic.Cyclopentadienyl anion $(C_5H_5^-)$ has $2$ double bonds ($4 \pi$ electrons) and a lone pair on the $sp^3$ carbon,which participates in resonance,providing a total of $6 \pi$ electrons. This makes it aromatic.Therefore,the cyclopentadienyl anion is the correct aromatic species.

Which aromatic compound has two double bonds and a five-membered ring?

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