-Isomers are molecules that have the same molecular formula, but have a different arrangement of the atoms in space.
-Structural Isomers are molecules which have the same molecular formula but have different connectivities. That is; the molecules have the same molecular formula, but their atoms have different arrangements or bonds.
-For example, butane and isobutane are structural isomers, also called chain isomers. In chain isomers, the carbon atoms are connected in different orders. Isobutane and butane have a molecular formula of C4H10.
