Cis-2-butene is an organic compound with the chemical formula C4H8. It is an alkene, meaning it contains a carbon-carbon double bond. The "cis" designation indicates that the two methyl groups (–CH3) attached to the double bond are on the same side, which affects its physical properties and reactivity compared to its trans isomer. This compound is commonly used in the production of various chemicals and plastics. It can be found in small amounts in petroleum and is also a product of certain industrial processes. Understanding cis-2-butene is important in fields like organic chemistry and materials science.