Characterized by the sharing of pairs of electrons between atoms, covalent bond is a chemical bonding. When the stable balance of attractive and repulsive forces between atoms share electrons, it creates a process known as covalent bonding, which includes many kinds of interaction, including σ-bonding, π-bonding, metal-to-metal bonding and agostic interactions.
The term itself, “covalent”, dates from 1939. The prefix “co-“ means “ in common”/ “jointly”. Thus, a “co-valent bond”, in essence, means that the atoms share “valence”. In the molecule H2, the hydrogen atoms share the two electrons via covalent bonding. When happening between atoms of similar electronegativities, covalency is even greater. Thus, covalent bonding does not necessarily require the two atoms be of the same elements, only that they be of comparable electronegativity.