What type of bond is formed when two nuclei share a pair of electrons?

A covalent bond is formed when two nuclei share a pair of electrons. This type of bond occurs between nonmetal atoms that have similar electronegativities; they are able to mutually attract the shared electrons, which helps both atoms achieve a more stable electron configuration. For example, in a molecule of hydrogen (H₂), each hydrogen atom shares one electron with the other, resulting in a strong bond that holds the two atoms together.

The nature of a covalent bond is characterized by the sharing of electrons, which distinguishes it from other types of bonds. Unlike ionic bonds, where electrons are transferred from one atom to another leading to charged ions, or metallic bonds, where electrons are delocalized and move freely among a lattice of metal ions, covalent bonds involve a direct sharing of electrons specifically between two atomic nuclei. Additionally, hydrogen bonds are a type of weak intermolecular attraction that occurs between molecules, typically involving hydrogen atoms and electronegative atoms like oxygen or nitrogen, and do not represent the sharing of electrons in the same manner as covalent bonds.