In
chemistry,
bond energy (
E) is the measure of
bond strength in a
chemical bond. It is the heat required to break one
mole of molecules into their individual atoms. For example, the
carbon-
hydrogen bond energy in
methane E(C–H) is the
enthalpy change involved with breaking up one molecule of methane into a carbon atom and 4 hydrogen
radicals divided by 4.
Bond energy (
E) should not be confused with
bond-dissociation energy. It is a roughly
transferable property, and
enthalpy of formation can typically be roughly approximated by simply adding tabulated values for bond energies for all bonds in a molecule, with an error of sometimes just a few percent. However, to get a better approximation is much more difficult.