Potassium nitrate Potassium nitrate Potassium nitrate is a chemical compound with the chemical formula KNO. It is an ionic salt of potassium ions K and nitrate ions NO, and is therefore an alkali metal nitrate. It occurs in nature as a mineral, niter. It is a source of nitrogen, from which it derives its name. Potassium nitrate is one of several nitrogen-containing compounds collectively referred to as saltpeter or saltpetre. Major uses of potassium nitrate are in fertilizers, tree stump removal, rocket propellants and fireworks. It is one of the major constituents of gunpowder (black powder) and has been used since the
Potassium alum a liquid known as "dousa" (), and used as an undercoat for paper sizing. Alum is an ingredient in some recipes for homemade modeling compounds intended for use by children. These are often called "play clay" or "play dough" for their similarity to "Play-Doh". Potassium alum was formerly used as a hardener for photographic emulsions (films and papers), usually as part of the fixer. It has now been replaced in that use by other chemicals. Potassium alum may be a weak irritant to the skin. Potassium alum Potassium alum, potash alum, or potassium aluminium sulfate is a chemical compound: the