Nitroglycerin (C3H5(ONO2)3), also called glyceryl trinitrate, is the nitrate ester of glycerol, made by its nitration; it was discovered by Ascanio Sobrero. Since it causes vasodilation, it is used to relieve angina. Its major use, however, is as a very powerful high explosive, though its sensitivity to shock renders it unsafe unless used in the form of dynamite or blasting gelatin. It is a colorless, oily liquid. Molecular weight 227.1, melting point 13°C.