Potassium nitrite (distinct from potassium nitrate) is the 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.
Potassium nitrate is a chemical compound with the chemical formula KNO3. It is an ionic salt of potassium ions K+ and nitrate ions NO3−, and is therefore an alkali metal nitrate. It occurs in nature as a mineral, niter (or nitre in the UK). It is a source of nitrogen, and nitrogen was named after niter.
