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 chromate Potassium chromate Potassium chromate is the inorganic compound with the formula (KCrO). This yellow solid is the potassium salt of the chromate anion. It is a common laboratory chemical, whereas sodium chromate is important industrially. It is a class two carcinogen as it contains hexavalent chromium. Two crystalline forms are known, both being very similar to the corresponding potassium sulfate. Orthorhombic β-KCrO is the common form, but it converts to an α-form above 66 °C. These structures are complex, although the sulfate adopts the typical tetrahedral geometry. It is prepared by treating potassium dichromate with potassium hydroxide. In solution, the