The average bond strength of a carbon – carbon single bond is 346 kJ mol-1 and a carbon = carbon double bond has a bond strength of 602 kJ mol-1.
To break carbon-carbon bonds requires large amounts of energy, meaning that the carbon skeleton is particularly stable. Organic compounds react in many different ways, but the carbon skeleton is rarely broken. For this reason, the atoms that are attached to the carbon skeleton are very important as they often confer reactivity to the molecule. Such atom or groups are called ‘functional groups’ – they give the molecule functionality.
Common functional groups
|Atom or grouping||name|
|-F, -Cl, -Br, -I||halide ‘group’|
|-COOH||carboxylic acid group|
Groups or atoms may also be used to join two carbon chains together. Such groups are sometimes called ‘linkages’
|Linking atom or group||name|