<Tr> <Td> </Td> <Td> </Td> </Tr> <Tr> <Td> Cyclohexane </Td> <Td> hex - 1 - ene </Td> </Tr> <P> For two molecules to be functional isomers, they must contain key groups of atoms arranged in particular ways . Some of the best examples come from organic chemistry . C H O is a molecular formula . Depending on how the atoms are arranged, it can represent two different compounds dimethyl ether CH - O - CH or ethanol CH CH - O-H . Dimethyl ether and ethanol are functional isomers . The first is an ether . The carbon chain - oxygen - carbon chain functionality is called an ether . The second is an alcohol . The carbon chain - oxygen - hydrogen functionality is called an alcohol . </P> <P> If the functionalities stay the same, but their locations change, the structural isomers are not functional isomers. 1 - Propanol and 2 - propanol are structural isomers, but they are not functional isomers . Both of them are alcohols . The functional group (carbon chain - O-H) is present in both of these compounds, but they are not the same . </P>

Structural formula for an alcohol that is an isomer of diethyl ether