ORGANIC CHEMISTRY - Structure and Bonding

The main feature of organic chemistry is the covalent bond. The covalent bond, formed as a result of sharing of electrons between two atoms, is generally called a <b>Chemical Bond</b>. Lewis first presented the concept of covalent bond in organic chemistry. These were subsequently classified into polar and non-polar bonds, depending upon the electonegativitiesof the bonded atoms. A knowledge of the nature and strength of bonds is essential for understanding the structural concept of organic molecules. Before studying the synthesis and determination of structure of organic compounds, the study, both chemical and kinetic, of organic reactions.

<b>Various terms used in Structure and Bonding :-</b>

<b>Bond Length :-</b> The interatomic or internuclear distance in a covalent molecule is known as bond length. Bond length are generally affected by the hybridization, electronegativity, steric effect or delocalization.

<b>Bond Angles :-</b> An angle between adjacent bonds in polyatomic molecule is called bond angle. The shape of the molecule are dependent on the bond angles.

<b>Bond Energy :-</b> Bond energy is the average bond dissociation energy of particular type of bonds in multiatomic molecule. It is simply denoted by 'E'. Bond energy is measure the strength of a bond, greater the bond energy, stronger is the bond.

<b>Localized Bond :-</b> If the electron forming a covalent bond remain confined to the space between the two bonded atom only, such electrons are called localized electron and the bond formed by these electrons are known as localized bond.

<b>Delocalized Bond :-</b> If the electron forming a covalent bond are not confined to the space between the two bonded atoms, the electrons are called delocalized electrons and bond formed by these electrons are known as the delocalized bond.

<b>Resonance Energy :-</b> The concept of resonance has been developed by analogy to quantum and wave mechanics and applied to organic structural representations. The difference in energy between the resonance hybrid structure and the most stable chemical structure, is known as a resonance energy.