Copper sulfate pentahydrate (chemical formula: CuSO4·5H2O) namely blue alum, barium, blue triclinic crystal, easy to weathering in dry air, heat to 190ºC to lose 4 molecules of crystal water, Chemicalbook to 258ºC into anhydrous salt. Poisonous. Soluble in water, insoluble in ethanol. Can be used as a pesticide, harmful if swallowed, irritates eyes and skin, and can have long-term adverse effects on the aquatic environment.