Butyl iodide (1-iodobutane) is an organic compound which is an iodo derivative of butane. It is used as an alkylating agent.
The compounds sec-butyl iodide (2-iodobutane), isobutyl iodide (1-iodo-2-methylpropane), and tert-butyl iodide (2-iodo-2-methylpropane) are structural isomers of butyl iodide.