Copper(I) chloride, or cuprous chloride, has the chemical formula CuCl. It is a white, almost insoluble salt which is slowly oxidized by air.
Pure samples of copper(I) chloride appear as white, dense, cubical crystals. As it is slowly oxidized in air, older samples may appear dirty green or brown.
Copper(I) chloride can be prepared by reduction of copper(II) ions in presence of chloride ions. Possible methods include bubbling sulfur dioxide through an aqueous solution of copper(II) chloride, or heating a solution of copper sulfate, sodium chloride and ascorbic acid. It can also be produced by boiling copper(II) chloride and copper metal in hydrochloric acid.
Copper(I) chloride can be used to make copper oxychloride by oxidation in air.
Cuprous chloride is irritant and corrosive to eyes and skin. Protection clothing should be worn when handling it.
Copper(I) chloride, Wikipedia (http://en.wikipedia.org/wiki/Copper%28I%29_chloride).