Characteristic

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. 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.It is one of the major constituents of gunpowder (black powder).

Chemical formula:KNO₃

Molar mass:101.1032 g/mol

Appearance:white solid

Odor:odorless

Density:2.109 g/cm³ (16 °C)

Melting point:334 °C (633 °F; 607 K)

Boiling point:400 °C (752 °F; 673 K) (decomposes)

Solubility in water:133 g/L (0 °C);242 g/L (20 °C);2439 g/L (100 °C)

Solubility:slightly soluble in ethanol;soluble in glycerol, ammonia

Basicity (pKb):15.3

Magnetic susceptibility (χ):−33.7·10−6 cm³/mol

Refractive index (nD):1.335, 1.5056, 1.5604

Crystal structure:Orthorhombic, Aragonite

Application

Potassium nitrate has several applications. It is used as an oxidizer, food preservative, fertilizer, and an active ingredient of condensed aerosol fire suppression systems. It is a powerful nitrating agent in sulfuric acid medium. In addition, it also used as an electrolyte in a salt bridge and thermal storage medium in power generation systems. Ternary salts containing potassium nitrate have been reported to improve the heat storage capacity in the molten salts.