CuCl22H2O

Copper(II) chloride dihydrate, with the chemical formula CuCl2·2H2O, is a crystalline solid. It is a hydrated salt of copper(II) chloride. This compound typically appears as blue or greenish-blue crystals. It is soluble in water, forming a blue solution. The anhydrous form, CuCl2, is a yellowish-brown solid. The dihydrate readily loses its water molecules upon heating.

CuCl2·2H2O is formed when copper(II) chloride is crystallized from an aqueous solution. It is an important laboratory reagent. In industrial applications, it finds use as a catalyst, a mordant in dyeing textiles, and in the production of pigments. Its catalytic properties are utilized in various organic synthesis reactions, such as the Wacker process for oxidizing ethylene to acetaldehyde.

The compound can be prepared by reacting copper metal or copper oxides with hydrochloric acid, followed by evaporation and crystallization to obtain the dihydrate form. It is important to handle copper(II) chloride dihydrate with care, as it can be irritating to the skin and eyes. It is also considered harmful if swallowed.