Phenethylamine is a primary amine, the amino-group being attached to a benzene ring through a two-carbon, or ethyl group. It is a colourless liquid at room temperature that has a fishy odor, and is soluble in water, ethanol and ether. Its density is 0.964 g/ml and its boiling point is 195 °C. Upon exposure to air, it combines with carbon dioxide to form a solid carbonate salt. Phenethylamine is strongly basic, pK = 4.17 (or pK = 9.83), as measured using the HCl salt, and forms a stable crystalline hydrochloride salt with a melting point of 217 °C.