Copper(I) acetylide, copper carbide or cuprous acetylide, is a chemical compound with the formula Cu2C2. It is a copper(I) salt of acetylene. It consists of Cu+ cations and acetylide anions −C≡C−, with the triple bond between the two carbon atoms. Although never characterized by X-ray crystallography, the material has been claimed at least since 1856. One form is claimed to be a monohydrate with formula Cu2C2·H2O. Copper(I) acetylide is a reddish-brown explosive powder.