noun
: a chloride of copper:
a. : a white poisonous powder CuCl made by reducing cupric chloride and used chiefly as a catalyst and as an absorbent of carbon monoxide — called also copper(I) chloride, cuprous chloride
b. : a yellowish brown deliquescent anhydrous powder CuCl 2 made by heating copper in chlorine or a green crystalline dihydrate CuCl 2 .2H 2 O made by evaporating cupric oxide in hydrochloric acid, both being used chiefly as a mordant in dyeing and printing and in some metallurgical processes — called also copper(II) chloride, cupric chloride
c. : any of various basic chlorides (as a brown powder CuCl 2 .3CuO) or mixtures formed on exposure of cupric chloride to air used as pigments and fungicides — called also copper oxychloride