Copper (I) chloride with hazard pictograms. Copper (I) chloride (CuCl) has a molar mass of 98.999 grams per mole. It is also known as cuprous chloride, dicopper dichloride, copper monochloride and nantokite (its natural form). Copper(I) chloride is an inorganic chloride of copper. Industrially, it is used in various processes in petroleum production, pigments for inks, toners and paints, and in plastic and rubber products. It is used in agrochemicals and as a pesticide against molluscs.