Butene is not a single molecule, but rather a group of isomers, meaning molecules with the same chemical formula but different structural arrangements.

The general formula for butene is C₄H₈.

Here are the four common isomers of butene:

* 1-Butene: The double bond is at the end of the carbon chain.

* cis-2-Butene: The double bond is in the middle of the carbon chain, with both hydrogens on the same side.

* trans-2-Butene: The double bond is in the middle of the carbon chain, with the hydrogens on opposite sides.

* Isobutene (2-methylpropene): The carbon chain is branched, with the double bond at the end.

You can see these structures illustrated in most chemistry textbooks or online resources.