Physical and chemical properties:

Blue green rhombic crystal system. Relative density 2.54. It is prone to deliquescence in humid air and weathering in dry air. Easy to dissolve in water, soluble in alcohol, ammonia, and acetone. It also has certain solubility in ether and ethyl acetate, making it a commonly used catalyst in organic reactions (especially in hydrocarbon activation reactions). Its aqueous solution is weakly acidic. Heating to 100 ℃ results in the loss of 2 crystalline water, but at high temperatures, it is prone to hydrolysis and difficult to obtain anhydrous salts. When crystallization is generated from copper chloride aqueous solution, dihydrate is obtained at 26-42 ℃, tetrahydrate is obtained below 15 ℃, trihydrate is obtained at 15-25.7 ℃, monohydrate is obtained above 42 ℃, and anhydrous is obtained at 100 ℃. Low toxicity, commonly used for swimming pool disinfection.

Main use:

① Used as a catalyst for chemical reactions such as halogenation of hydrocarbons and oxidation of organic compounds;

② Used as a food additive in the food industry;

③ Used in the printing and dyeing industry as a mordant, dye coloring agent, and wood preservative;

④ Used in the petroleum industry as deodorizing, desulfurization, and purification agents;

⑤ Used as a water purification disinfectant in water treatment;