A class of compounds with fishy odor and lachrymatory properties. They are named from their similarity in structure to mustard gas (dichlorodiethyl sulfide). The sulfur of the mustard gas is replaced by an amino nitrogen. Typical nitrogen mustards are halogenated alkylamines, such as methyl bis(2-chloroethyl)amine: (ClCH2CH2)2NCH3. Other examples are triethylene melamine, triethylene thiophosphoramide, and triethylene phosphoramide.