Answer:
Double and Triple Covalent Bonds
Learning Objective
Describe the types of orbital overlap that occur in single, double, and triple bonds
Key Points
Double and triple covalent bonds are stronger than single covalent bonds and they are characterized by the sharing of four or six electrons between atoms, respectively.
Double and triple bonds are comprised of sigma bonds between hybridized orbitals, and pi bonds between unhybridized p orbitals. Double and triple bonds offer added stability to compounds, and restrict any rotation around the bond axis.
Bond lengths between atoms with multiple bonds are shorter than in those with single bonds.
Terms
bond strengthDirectly related to the amount of energy required to break the bond between two atoms. The more energy required, the stronger the bond is said to be.
bond lengthThe distance between the nuclei of two bonded atoms. It can be experimentally determined.
orbital hybridizationThe concept of mixing atomic orbitals to form new hybrid orbitals suitable for the qualitative description of atomic bonding properties and geometries.
atomic orbitalsThe physical region in space around the nucleus where an electron has a probability of being.
Double and Triple Covalent Bonds
Covalent bonding occurs when electrons are shared between atoms. Double and triple covalent bonds occur when four or six electrons are shared between two atoms, and they are indicated in Lewis structures by drawing two or three lines connecting one atom to another. It is important to note that only atoms with the need to gain or lose at least two valence electrons through sharing can participate in multiple bonds.
Bonding Concepts
Hybridization
Double and triple bonds can be explained by orbital hybridization, or the ‘mixing’ of atomic orbitals to form new hybrid orbitals. Hybridization describes the bonding situation from a specific atom’s point of view. A combination of s and p orbitals results in the formation of hybrid orbitals. The newly formed hybrid orbitals all have the same energy and have a specific geometrical arrangement in space that agrees with the observed bonding geometry in molecules. Hybrid orbitals are denoted as spx, where s and p denote the orbitals used for the mixing process, and the value of the superscript x ranges from 1-3, depending on how many p orbitals are required to explain the observed bonding.
