n. Any binary compound of carbon and a more electropositive elementn. The polyatomic ion C22−, or any of its salts.n. The monatomic ion C4−, or any of its salts.n. A carbon-containing alloy or doping of a metal or semiconductor, such as steel.n. Tungsten carbide.n. trivial name for calcium carbide (CaC2), used to produce acetylene in bicycle lamps in the early 1900s.