KNO3. Potassium nitrate is white granular or crystalline powder at room temperature, odorless and toxic, with brine irritating flavor, weak hygroscopicity, soluble in water, soluble in liquid ammonia and propanetriol, slightly soluble in alcohol, insoluble in ethanol. Potassium nitrate is a strong oxidizing agent, it will decompose and produce potassium nitrite and oxygen when heated at high temperature, there is a danger of combustion and explosion when contacting with heat source and reducing agent. The molar mass of potassium nitrate is 101.103g/mol, the boiling point is 400℃ under standard atmospheric pressure, the melting point is 333~334℃, and the density is 2.1g/cm3 at room temperature.