Derivatives of ammonia (nh3) in which one or more h are replaced by alkyl or aryl groups. Classified as 1 , 2 , or 3 depending on number of h atoms of ammonia that are replaced. The 3 atoms / groups bonded to the n in amines assume a trigonal pyramidal geometry. Aliphatic amine: amine in which n is bonded only to alkyl groups. Aromatic amine: amine in which n is bonded to one or more aryl groups. Heterocyclic amine: amine in which n is one of the atoms of a ring. Heterocyclic aromatic ring: amine in which n is one of the atoms of an aromatic ring. Amines are polar compounds, both primary and secondary amines form intermolecular h bonds. All classes of amines form h bonds with water and are more soluble in water. Like ammonia, all amines are weak bases. All aliphatic amines have about the same base strength and are slightly stronger bases than ammonia.