Dative Covalent Bonding (AQA A-Level Chemistry): Revision Notes

A dative covalent bond, also known as a coordinate bond, is a type of covalent bond where both electrons in the shared pair come from the same atom. It occurs when one atom donates a lone pair of electrons to form a bond with another atom that has an empty orbital.

Example: Ammonium Ion ($NH_4^+$) A classic example of dative bonding is the formation of the ammonium ion ($NH_4^+$):

• Ammonia ($NH₃$) has a lone pair of electrons on the nitrogen atom.
• $H⁺$(a proton) has no electrons and can accept a lone pair.
• The nitrogen in ammonia donates its lone pair to the $H⁺$ ion, forming a dative bond and producing $NH₄⁺$(ammonium ion). This can be represented as:

In this reaction, the nitrogen atom provides both electrons for the bond between N and H⁺.

Summary

• Dative covalent bonds form when one atom donates both electrons in a shared pair.
• These bonds are represented using an arrow pointing from the electron donor to the acceptor.
• Once formed, dative bonds are treated as standard covalent bonds.