Methylene (IUPAC name: Methylidene, also called carbene or methene) is an organic compound with the chemical formula  (also written ). It is a colourless gas that fluoresces in the mid-infrared range, and only persists in dilution, or as an adduct.
Methylene is the simplest carbene. It is usually detected only at very low temperatures, or as a short-lived intermediate in chemical reactions.