Hydrocarbons and halides

We have already seen some examples of very common functional groups: ethene, for example, contains a carbon-carbon double bond. This double bond is referred to, in the functional group terminology, as an alkene.

The carbon-carbon triple bond in ethyne is the simplest example of an alkyne function group.

What about ethane? All we see in this molecule is carbon-hydrogen and carbon-carbon single bonds, so in a sense we can think of ethane as lacking a functional group entirely. However, we do have a general name for this ‘default’ carbon bonding pattern: molecules or parts of molecules containing only carbon-hydrogen and carbon-carbon single bonds are referred to as alkanes. If the carbon of an alkane is bonded to a halogen, the group is now referred to as a haloalkane (fluoroalkane, chloroalkane, etc.). Chloroform, CHCl₃, is an example of a simple haloalkane.