Trimethylamine (TMA) is an organic compound with the formula N(CH3)3. This colorless, hygroscopic, and flammable tertiary amine has a strong “fishy” odor in low concentrations and an ammonia-like odor at higher concentrations. It is a gas at room temperature but is usually sold in pressurized gas cylinders or as a 40% solution in water. TMA is a nitrogenous base and can be readily protonated to give trimethylammonium cation. Trimethylammonium chloride is a hygroscopic colorless solid prepared from hydrochloric acid. Trimethylamine is a good nucleophile, and this reaction is the basis of most of its applications.