Saltpeter definition

Thermal Stability. In general, pnre AN may be considered stable up to its mp (169.9°) Reports of early investigators, such as Berthelot (Refs 1 8), that the salt begins to decompose at temps as low as 100°, were apparently correct because the substance was not pure. In the days when nitric acid (used for the manuf of AN) was prepd from Chile saltpeter, some nitrites and chlorides, as well as other impurities, remained in the AN, and it was apparently due to them that the stability of the product was not satisfactory. Tram it Velde (Ref 49) found that as little as 0 1% of Amm or Na chloride increases greatly the probability of decompn of AN, while 1—2% of such impurities are definitely the cause of increase of decompn of molten AN... 

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