nitrate
chemical compound
nitrate, any member of either of two classes of compounds derived from nitric acid, HNO3. The salts of nitric acid are ionic compounds containing the nitrate ion, NO-3, and a positive ion, such as NH4+ in ammonium nitrate. Esters of nitric acid are covalent compounds having the structure R―O―NO2, in which R represents an organic combining group, such as ethyl (C2H5) in ethyl nitrate. See also nitro compound.