Copper(I) Iodide

Copper(I) Iodide, also known as cuprous iodide, is an inorganic compound with the chemical formula CuI. Pure copper(I) iodide is white, but samples are often tan or even occasionally reddish brown, but such color is due to the presence of impurities. Many compounds containing the iodide anion oxidise in air to form brown molecular iodine.

Synthesis
Copper(I) iodide can be prepared by heating iodine and copper in concentrated hydroiodic acid, HI. In the laboratory, however, copper(I) iodide is prepared by simply mixing an aqueous solution of sodium or potassium iodide and a water soluble copper(II) salt such copper sulfate.The CuI2 immediately decomposes to iodine and insoluble copper(I) iodide, releasing molecular iodine.