Colorless crystals. It exists as two kinds of crystals, semi-molecular crystalline water type and anhydrous type. Semi-molecular crystalline water form with melting point 78 °C, slightly soluble in water (1:250), soluble in ethanol (1:1), glycerol (1:10), ether, chloroform and volatile oil. The anhydrous type has a melting point of 9Chemicalbook 7 °C, a boiling point of 167 °C, and a boiling point of 135 °C (32.7 kPa). Soluble in hot water, 1g can be dissolved in 1ml ethanol or 10ml glycerol, soluble in ether, petroleum ether, acetone, chloroform, glacial acetic acid, oil. It is easy to sublimate when heated and can volatilize with water vapor. Camphor-like odor.