nitroglycerin, C₃H₅N₃O₉, colorless, oily, highly explosive liquid. It is the nitric acid triester of glycerol and is more correctly called glycerol trinitrate. It is insoluble in water but soluble in ether, acetone, benzene, and chloroform. An unstable compound, nitroglycerin decomposes with explosive violence when heated or jarred. It is mixed with an absorbent material to form dynamite (which is not so sensitive to slight shocks) and is also used as a component of smokeless powder. Nitroglycerin was discovered (c.1847) by the Italian chemist Ascanio Sobrero and was first produced commercially by Alfred Nobel. It is used medicinally to provide temporary relief from the symptoms of angina pectoris; the body converts it to nitric oxide, which causes narrowed blood vessels to relax.