Sodium nitrite is the inorganic compound with the chemicals formula NaNO2 . It is a white to slight yellowish crystalline powder that is very soluble in water and is hygroscopic. It is a useful precursor to a variety of organic compounds, such as pharmaceuticals, dyes, and pesticides, but it is probably best know as a food additive to prevent botulism.
The main use of sodium nitrite is for the industrial production of organonitrogen compounds. It is a reagent for conversion of amines into diazo compounds, which are key precursors to many dyes, such as diazo dyes.Nitroso compounds are produced from nitrites. These are used in the rubber industry.
Other applications include uses in photography. It may also be used as an electrolyte in electrochemical grinding manufacturing processes, typically diluted to about 10% concentration in water. It is used in a variety of metallurgical applications, for phosphatizing and detinning. Sodium nitrite also has been used in human and veterinary medicine as a vasodilator, a bronchodilator, and an antidote for cyanide poisoning.