Multiple bond

Multiple bond refers to a type of chemical bond in which two atoms share more than one pair of electrons between them. This bonding is a key concept in the field of chemistry, particularly in the study of molecular structure and bonding theories. Multiple bonds include double bonds, where two pairs of electrons are shared, and triple bonds, where three pairs of electrons are shared. These bonds are stronger and shorter than single bonds, where only one pair of electrons is shared.

Types of Multiple Bonds

Multiple bonds can be classified into two main types: double bonds and triple bonds.

Double Bonds

A double bond (symbolized as =) involves the sharing of two pairs of electrons between two atoms. It is commonly found in organic compounds, such as alkenes, which contain a carbon-carbon double bond. Double bonds are characterized by their rigidity, which restricts the rotation around the bond axis, leading to the existence of cis-trans isomerism in certain compounds.

Triple Bonds

A triple bond (symbolized as ≡) involves the sharing of three pairs of electrons between two atoms. This type of bond is stronger and shorter than both single and double bonds. Triple bonds are typically found in alkynes, with acetylene (ethyne) being the simplest example, where two carbon atoms are connected by a triple bond.

Properties of Multiple Bonds

Multiple bonds have distinctive physical and chemical properties:

• Strength and Length: Multiple bonds are stronger and shorter than single bonds. The increased number of shared electrons results in a stronger attraction between the bonded atoms, making the bond more difficult to break.
• Bonding Orbitals: The formation of multiple bonds involves the overlap of more than one pair of atomic orbitals, including both σ (sigma) and π (pi) bonds. The first pair of electrons forms a sigma bond, while the additional pairs form pi bonds, which are responsible for the unique properties of multiple bonds.
• Reactivity: Compounds with multiple bonds often exhibit higher reactivity compared to those with single bonds. This is due to the presence of pi bonds, which are more exposed and thus more susceptible to attack by electrophiles and nucleophiles.

Significance in Organic Chemistry

In organic chemistry, multiple bonds are crucial for the structure and reactivity of many compounds. They are involved in various types of chemical reactions, such as addition reactions, polymerizations, and hydrogenations. The presence of multiple bonds in a molecule can also influence its physical properties, such as boiling and melting points, as well as its solubility in different solvents.

See Also

• Chemical bond
• Molecular orbital theory
• Valence bond theory
• Hybridization (chemistry)