Chili Saltpetre

Chili Saltpetre consists of nitrate of soda, NaNO₃. It hence differs from nitre or saltpetre, KNO₃, only in the substitution of sodium for potassium. It crystallises in rhombohedra closely resembling cubes, and is also called cubic saltpetre. It occurs largely as a deposit on the soil in Peru and Bolivia. Being cheaper, it is largely used instead of nitre for the preparation of nitric acid. It cannot be used in place of nitre for the production of gunpowder, however, as it attracts moisture from the air and deliquesces. Small quantities of sodium iodate, NaI0₃, are generally present also, and it is hence employed as a source of iodine.