resonating structures nitro phenol
There are two common isomers:
Ortho-nitrophenol (–NO? at ortho position to –OH)
Para-nitrophenol (–NO? at para position to –OH)
Both exhibit resonance due to the interaction between the lone pair of electrons on –OH and the π-electrons of the benzene ring.
–OH group is an electron-donating group (+R effect), donating lone pair into the ring.
–NO? is an electron-withdrawing group (–R effect), withdrawing electron density from the ring.
These opposing effects create resonance structures that stabilize the molecule.