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salts of nitric acid, HNO3. Colorless crystalline compounds that are stable at ordinary temperatures; at high temperatures they release oxygen readily and are strong oxidizing agents (for example, 2KNO3 = 2KNO2 + O2). All nitrates are highly soluble in water.
Nitrates are produced by the action of nitric acid on metals, metal oxides, and certain salts in neutral or slightly acidic solutions by exchange reactions or by the action of NO2 on bases (nitrites are also produced by the latter reaction). The nitrates of a number of elements (sodium, potassium, and calcium) occur naturally. Of these, only deposits of sodium nitrate (Chile saltpeter) are of practical importance.
Nitrates are widely used as fertilizers (sodium, potassium, ammonium, and calcium salts), in the production of explosives (ammonium and barium salts), and as mordants in dyeing (chromium, iron, aluminum, and copper salts). Ammonium nitrates and the nitrates of the alkali and alkaline-earth metals are also called saltpeters.