Covalent compound

Covalent compounds are a class of chemical compounds characterized by the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding. Covalent bonding is one of the key types of chemical bonding, alongside ionic bonding and metallic bonding.

Overview

Covalent compounds are formed when two or more nonmetal atoms bond by sharing valence electrons. The electrons are shared rather than transferred, as in ionic bonding, allowing each atom to achieve a full outer shell of electrons and thus reach a more stable state. This type of bond is prevalent in organic compounds, making it a fundamental concept in organic chemistry.

Characteristics of Covalent Compounds

Covalent compounds exhibit several distinctive characteristics:

• They have low melting and boiling points compared to ionic compounds.
• They are often gases, liquids, or soft solids at room temperature.
• They do not conduct electricity in any state, as they do not have free ions or electrons.
• They show varying degrees of solubility in water, but are often soluble in nonpolar solvents.

Types of Covalent Bonds

Covalent bonds can be classified into three types based on the number of shared electron pairs:

• Single bonds involve the sharing of one pair of electrons (e.g., H2).
• Double bonds involve the sharing of two pairs of electrons (e.g., O2).
• Triple bonds involve the sharing of three pairs of electrons (e.g., N2).

Polarity of Covalent Bonds

The polarity of covalent bonds is determined by the electronegativity difference between the bonded atoms. Bonds can be:

• Nonpolar covalent bonds, where electrons are shared equally because atoms have similar electronegativities.
• Polar covalent bonds, where electrons are shared unequally, leading to a distribution of charge and the formation of partial positive and negative poles.

Formation of Covalent Compounds

The formation of a covalent compound involves the overlap of atomic orbitals. The Lewis structure is a common way to represent covalent bonds in molecules, showing how valence electrons are shared between atoms.

Examples of Covalent Compounds

• Water (H2O) is a polar covalent compound where oxygen shares electrons with two hydrogen atoms.
• Carbon dioxide (CO2) involves double bonds between carbon and oxygen atoms and is a nonpolar molecule overall due to its linear geometry.

Applications of Covalent Compounds

Covalent compounds have wide applications in everyday life and various industries. They are essential in biological molecules like DNA and proteins, in materials science for polymers and nanomaterials, and in pharmaceuticals for drug development.