Coordination link

Formation of an ammonia and trifluoride aduct, which involves the formation of a coordinated covalent link.

The coordination or coordinate bond, also known as the bipolar bond, is a covalent bond in which a pair of electrons shared by two atoms is contributed by only one one of them. The atom that contributes the pair of electrons is called the donor, and the one that receives it, the receiver.

Typically a coordination bond is formed when a Lewis base donates an electron pair to a Lewis acid. Chemical complexes are molecular structures in which a central atom (usually a metal cation) is found bound to other molecules called ligands are also formed by this type of bond.

This description of bonding is characteristic of valence bond theory and has no place in molecular orbital theory or ligand field theory of coordination complexes.