Potassium nitrate (data page)

Potassium nitrate, also known as saltpeter, is a chemical compound with the formula KNO₃. It is an ionic salt of potassium ions (K⁺) and nitrate ions (NO₃⁻). It is a naturally occurring mineral source of nitrogen, and is one of several nitrogen-containing compounds collectively referred to as saltpeter.

In its pure form, potassium nitrate is a white, crystalline solid. It is soluble in water, though its solubility increases significantly with temperature. It is practically insoluble in alcohol.

Potassium nitrate has a variety of uses, including as a fertilizer, oxidizer in gunpowder and other explosives, food preservative (particularly in cured meats), and as a component in some toothpastes for sensitive teeth. It has also been used historically in the production of nitric acid.

Industrially, potassium nitrate can be produced through several methods, including the reaction of ammonium nitrate with potassium hydroxide, or the reaction of potassium chloride with sodium nitrate. It can also be mined from natural deposits.

When heated, potassium nitrate decomposes to form potassium nitrite and oxygen. It is a relatively stable compound under normal conditions, but it is a strong oxidizer and should be handled with care, especially when in contact with combustible materials.