Coordinate Covalent Bond
Definition and meaning of Coordinate Covalent Bond in chemistry.
A coordinate covalent bond (also called a dative bond) is a covalent bond in which one atom supplies both of the shared electrons, while the other atom contributes none but has an empty orbital to accept them.
In more detail
The electron-pair donor is a Lewis base with a lone pair, and the acceptor is a Lewis acid with a vacant (often empty p or d) orbital. Once the bond forms, the shared electron pair is indistinguishable from electrons in an ordinary covalent bond, so the resulting bond has identical length and strength to a bond formed by two atoms each donating one electron. Coordinate covalent bonds are essential for describing polyatomic ions, adduct formation between Lewis acids and bases, and the metal-ligand bonds in coordination complexes.
Key facts
| Also called | Dative bond |
|---|---|
| Example ion formula | NH4+ |
| Electron source | Both electrons from one atom (donor) |
| Field | General Chemistry |
When ammonia (NH3) reacts with a hydrogen ion (H+), the nitrogen atom's lone pair forms a coordinate covalent bond to the empty 1s orbital of H+, producing the ammonium ion (NH4+); all four N–H bonds in NH4+ are then equivalent.
Frequently asked questions
Is a coordinate covalent bond weaker than a normal covalent bond?
No. Once formed, it is a regular covalent bond; the electron pair is shared equally in behavior with other bonding pairs, giving the same bond length and strength as any covalent bond between those atoms.
Where else do coordinate covalent bonds appear besides NH4+?
They occur in the hydronium ion (H3O+), Lewis acid-base adducts such as BF3·NH3, and throughout coordination chemistry, where ligands donate electron pairs to metal cations to form metal-ligand bonds.