BE meaning in Chemistry ?

In chemistry, bond energy (BE), also called the mean bond enthalpy or average bond enthalpy is the measure of bond strength in a chemical bond. IUPAC defines bond energy as the average value of the gas-phase bond-dissociation energy (usually at a temperature of 298.15 K) for all bonds of the same type within the same chemical species. The larger the average bond energy, per electron-pair bond, of a molecule, the more stable and lower-energy the molecule.

The bond dissociation energy (enthalpy) is also referred to asbond disruption energy, bond energy, bond strength, or bindingenergy (abbreviation: BDE, BE, or D). It is defined as the standardenthalpy change of the following fission: R - X → R + X. The BDE,denoted by Dº(R - X), is usually derived by the thermochemicalequation,

The enthalpy of formation ΔHfº of a large number of atoms, free radicals, ions,clusters and compounds is available from the websites of NIST,NASA, CODATA, and IUPAC. Most authors prefer to use theBDE values at 298.15 K.

For example, the carbon–hydrogen bond energy in methane BE(C–H) is the enthalpy change (∆H) of breaking one molecule of methane into a carbon atom and four hydrogen radicals, divided by four. The exact value for a certain pair of bonded elements varies somewhat depending on the specific molecule, so tabulated bond energies are generally averages from a number of selected typical chemical species containing that type of bond.

Bond energy (BE) is the average of all bond-dissociation energies of a single type of bond in a given molecule. The bond-dissociation energies of several different bonds of the same type can vary even within a single molecule. For example, a water molecule is composed of two O–H bonds bonded as H–O reference