Coordinate Covalent Bond
Definition and meaning of Coordinate Covalent Bond in chemistry.
A coordinate covalent bond is a chemical bond where one atom supplies both shared electrons. The other participating atom brings zero electrons but provides an empty orbital to accept the pair. This specific type of connection is also commonly known as a dative bond.
In more detail
The electron donor must act as a Lewis base possessing a free lone pair. The electron acceptor acts as a Lewis acid with a vacant orbital ready for electrons. This vacant space is often an empty energy orbital in the atom's outer valence shell.
Once the coordinate bond forms, it behaves exactly like an ordinary covalent bond. You cannot tell which atom originally provided the two electrons just by analyzing the final molecule. The resulting bond has the exact same bond length and strength as any normal covalent bond.
Students often mistakenly think a coordinate bond is weaker or somehow different from standard bonds. This connection is completely identical to a normal bond once the electron sharing actually begins. Coordinate covalent bonds are absolutely essential for understanding how complex polyatomic ions hold together.
They also explain how larger adduct molecules form when Lewis acids and bases directly react. Furthermore, these specific bonds build the entire foundation of metal-ligand connections found in transition metal chemistry.
Key facts
| Alternative name | Also called a dative bond in older chemistry textbooks |
|---|---|
| Donor role | One atom provides both electrons for the shared bond |
| Acceptor role | The other atom provides an empty orbital to hold the electrons |
| Final strength | Exactly as strong as a normal covalent bond once formed |
| Classic example | Forms when ammonia and a hydrogen ion create the ammonium ion |
We can see this clearly when ammonia gas reacts with a loose hydrogen ion. The nitrogen atom in the ammonia molecule holds one unshared lone pair of electrons. The hydrogen ion has lost its only electron and features a completely empty orbital. The nitrogen donates its lone pair into this empty space to form a coordinate covalent bond. This reaction produces the positively charged ammonium ion, written as the formula NH4+. After this process, all four nitrogen-hydrogen bonds in the molecule behave exactly the same way.
Frequently asked questions
Is a coordinate covalent bond weaker than a normal covalent bond?
No. Once the bond forms, it is a completely regular covalent bond. The electron pair is shared equally, giving it the same length and strength as any other bond.
Where else do coordinate covalent bonds appear besides the ammonium ion?
They appear constantly in chemistry. You will see them in hydronium ions, Lewis acid-base adducts, and carbon monoxide. They also connect every ligand to a metal in coordination complexes.
Can any atom form a coordinate covalent bond?
Not just any atom. One atom must have a non-bonding lone pair of electrons available. The other atom must have an empty valence orbital ready to accept those electrons.