Covalent Bond
A bond formed when two atoms share one or more pairs of electrons so that both achieve a stable configuration.
Formula / equation
A· + ·B → A:B
Unit
kJ/mol
In depth
Sharing occurs between atoms of similar electronegativity, usually two non-metals. The shared pair occupies the region between the nuclei, and because it lies along a specific axis the bond is directional — which is precisely why molecules have definite shapes. Strength rises and length falls as more pairs are shared.
Examples in the real world
The single bond in H₂, the double bond in O₂, and the triple bond in N₂ that makes nitrogen so unreactive.