Structure of AminesThe carbon to which the nitrogen is attached in an alkyl amine is sp3 hybridized, and in aryl amines it is sp2 hybridized. The nitrogen in the amines is sp3 hybridized. As you have probably noticed, the nitrogen present in an amine has an unshared electron pair. In alkyl amines, the substituents attached to the nitrogen atom are arranged in a pyramidal manner around the nitrogen. In aryl amines, this pyramidal mode is more flat compared to alkyl amines. Moreover, the unshared pair of electrons in aryl amines has the advantage of delocalization into the pi electrons in the aromatic ring.