Why is nitro group called an ambident group?

The nitro group ($-{\text{NO}}_2$) is called an ambident group because it can act as a nucleophile from two different sites during nucleophilic substitution reactions. This dual reactivity arises due to its resonance structures:

1. Nitrogen atom (–N⁻=O⁺) can donate a lone pair of electrons, acting as a nucleophile.
2. Oxygen atom (–N=O⁻) can also donate a lone pair, acting as a nucleophile.

For example, in the reaction with alkyl halides, the nitro group can attack via either nitrogen or oxygen, leading to different products (e.g., N-alkylation or O-alkylation). This dual reactivity makes it an ambident nucleophile.

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