Covalent Bond Examples

If you observe the world at a microscopic level, you realize that the complex structures of the world arise from clumping together of simpler units of matter called atoms. The electromagnetic force binds atoms together to form molecular compounds, which aggregate together to create even bigger molecules and polymers, which make life possible. This ascending order of complexity is made possible by the electromagnetic forces that exist between charged particles. Chemical bonding at the level of atoms through sharing or exchange of electrons makes the creation of molecules possible. Bonding between atoms can either be covalent or ionic bonding.

What is a Covalent Bond?

A covalent bond between atoms is formed when they share one or more pair of electrons among each other. These shared pair of electrons create a bond between the atoms, which binds them together into a singular unit, which we define to be the molecule. These shared electrons are the valence electrons of atoms which revolve in their outermost shells.

Each atom that forms a covalent bond tries to achieve stability by filling up the outermost electronic orbitals of atoms, which are still unoccupied. As the two atoms come together and share electrons, a bond is created by the electromagnetic force of attraction which exists between the atomic nuclei and the shared pair of electrons. There is also a force of repulsion between the electrons revolving around both atoms, which causes the molecule to get distorted. Since both atomic nuclei are attracted to the shared pair of electrons, a bond is created between the two atoms.

Depending on the electron affinity or electronegativity (tendency of atoms to attract electrons), the shared pair of electrons may be equally or unequally shared. If they are unequally shared, the molecule becomes 'polar' in the sense, that imbalance of charges is created within.

Examples

A covalent bond may exist between similar or different atoms. Here are some types of covalently bonded molecules which includes polar, non-polar and coordinate covalent bond.

• Water (H₂O): In this molecule two hydrogen atoms share their single electrons with the Oxygen atoms, which shares its own two electrons in return. This is an example of polar covalent bond, which is created because of higher electronegativity of oxygen.
• Hydrogen Molecule (H₂): This is a non-polar covalent bond example as an electron pair is equally shared between the two hydrogen atoms.
• Ammonium Chloride (NH₄Cl): This is a coordinate covalent bond example, where both electrons required for bonding are supplied by the same atom. This is a special case of covalent bonding.
• Hydrogen Chloride (HCl): This is another polar covalent bond example, where the electron pair is pulled more towards the chlorine atom, which has a higher electronegativity.

Here is a table listing molecules with polar and non-polar covalent bonds.

Polar Covalent Bond	Non-Polar Covalent Bond
Hydrogen Fluoride (HF)	Nitrogen (N2)
Ozone (O3)	Methane (CH4)
Ammonia (NH3)	Carbon Dioxide (CO2)
Hydrogen Sulfide (H2S)	Chlorine (Cl2)

These were some illustrative examples which should have given you an idea about the nature of this type of chemical bond. As discussed before, the sharing of electrons between the atoms which constitute the molecule is influenced by their individual electronegativity. The more unequal the electronegativity, more polar is the molecules formed. More matching the electronegativity, more equally shared the electrons are. Almost all organic molecules made up of carbon chains are covalently bonded. You will find plenty of examples of covalent bond in organic chemistry.

Chemistry is devoted to the study of a wide range of molecules ranging from the simplest like those of oxygen to the more complex molecules like DNA (Deoxyribonucleic Acid). Each of these molecules are held together by the covalent bonding which exists between its constituent atoms. Hope this article has considerably clarified the concept of covalent bond for you. Study more examples in greater detail, to understand molecular bonding more thoroughly.