Potassium nitrite is an inorganic compound with the chemical formula KNO2. It is an ionic salt of potassium ions K+ and nitrite ions NO2-, which forms a white or slightly yellow, hygroscopic crystalline powder that is soluble in water. It is a strong oxidizer and may accelerate the combustion of other materials. Like other nitrite salts such as sodium nitrite, potassium nitrite is toxic if swallowed, and laboratory tests suggest that it may be mutagenic or teratogenic.
Potassium nitrite can be obtained by the reduction of potassium nitrate. The production of potassium nitrite by absorption of nitrogen oxides in potassium hydroxide or potassium carbonate is not employed on a large scaled because of the high price of these alkalies. Furthermore, as potassium nitrite is highly soluble in water, that makes it difficult to be recovered.
Potassium nitrite is used as a food preservative, additive, and is used in curing meat.
Potassium nitrate is used to treat asthma and in topical formulations for sensitive teeth.
It is an oxidizer for fireworks and rockets.
Potassium nitrite is a component of condensed aerosol fire suppression systems, salt bridges in electrochemistry, heat treatment of metals, and thermal storage in power generators.