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sodium nitrate,chemical compound, NaNO3, a colorless, odorless crystalline compound that closely resembles potassium nitrate (saltpeter or niter) in appearance and chemical properties. It is soluble in water, alcohol, and liquid ammonia. Sodium nitrate is also called soda niter or Chile saltpeter. It is found naturally in large deposits in arid regions of Chile, Peru, Argentina, and Bolivia as caliche, a crude, impure nitrate rock or gravel. Natural deposits are the major source of sodium nitrate; it is also obtained in small amounts as a byproduct of chlorine production by the nitrosyl chloride process, in which sodium chloride (common salt) is reacted with nitric acid. Sodium nitrate is used in making potassium nitrate, fertilizers, and explosives. It was formerly an important raw material for the production of nitric acid.
NaNO3, a salt; colorless crystals. Density, 2.257 g/cm3; melting point, 308°C (decomposes into NaNO2 and O2 at higher temperatures). Solubility in water, 47.6 percent at 25°C and 64.3 percent at 100°C. It is a strong oxidizing agent. Sodium nitrate occurs naturally as Chile saltpeter. It is prepared industrially by reaction of nitric oxides and Na2CO3 solutions, with subsequent oxidation of the resulting NaNO2. It is used as a minor additive in the processing of meats (since it readily reduces to sodium nitrite).
In agriculture, sodium nitrate is used as a nitrogen fertilizer. It contains 16 percent nitrogen and not more than 2 percent moisture; it is hygroscopic, agglutinates very little during storage, and spreads readily. It is applied as a base fertilizer, and also as a row fertilizer and top dressing for various types of soil and all crops. It is most effective when applied under sugar beets and root vegetables (which require relatively large quantities of Na), and also wheat and barley, particularly (because of its physiological alkalinity) on acidic soddy-podzolic soils.