Coordinate Bond
A covalent bond in which both shared electrons are supplied by the same atom.
Formula / equation
A: + B → A→B
Unit
kJ/mol
In depth
Also called a dative bond, it forms when a species with a lone pair donates to one with a vacant orbital. Once formed it is indistinguishable from an ordinary covalent bond, since electrons carry no memory of their origin. Coordinate bonding is the basis of all Lewis acid–base chemistry and of coordination complexes.
Examples in the real world
NH₃ donating its lone pair to H⁺ to give NH₄⁺, and to BF₃ to give the adduct H₃N→BF₃.