Copper cyanide is an inorganic mixture that contains the formula CuCN. It is observed as an off white solid that occurs with two polymorphs, and impure samples will often be green because of the presence of their distinct impurities. The compound itself is very useful as a catalyst and in copper electroplating. It is also used as a reagent when preparing nitriles. Most types of cuprous cyanide are regularly, usually supplied as low temperature polymorph. It can typically be prepared with by way of a reduction of copper sulfate with sodium bisulfite at sixty degrees Celsius. Cuprous cyanide is most commonly used as a way of electroplating copper. The compound itself is very useful as a reagent in organic synthesis as well, especially in regioselective and stereoselective conjugate additions and allylations of certain compounds. These applications make it a very useful compound, however, caution should always be exercised in its handling.