White crystals. Odorless. The taste is bitter. It is hygroscopic. The precipitated from water contains 2 molecules of crystal water, which is lost in the air and weathered, and precipitated from concentrated hydrochloric acid or sulfuric acid is anhydrous crystal. It does not melt when heated, and at the same time liberates cyanide. 1 g is dissolved in about 200 ml of water and can form a supersaturated solution. Soluble in hot water, soluble in hot ethanol, pyridine, concentrated hydrochloric acid and sulfuric acid without decomposition, also soluble in sodium hydroxide and potassium hydroxide aqueous solution, insoluble in methanol, ether, acetone, benzene and chloroform. Relative density (d? 204) 2.500. Moderately toxic, half lethal dose (rat, oral) 500mg/kg. Irritating
