What is a dative covalent bond?

A dative covalent bond is a type of covalent bond where both electrons come from the same atom.

In more detail, a dative covalent bond, also known as a coordinate bond, is a special type of covalent bond. In a typical covalent bond, each atom provides one electron to form a pair of electrons, which is shared between the two atoms. However, in a dative covalent bond, one atom provides both electrons that form the shared pair. This usually happens when an atom with a lone pair of electrons donates them to an atom that is short of electrons to complete its valence shell.

For example, consider the formation of the ammonium ion (NH4+). In this case, the nitrogen atom in ammonia (NH3) has a lone pair of electrons. A hydrogen ion (H+), which lacks electrons, can accept this pair to form a dative covalent bond with nitrogen, resulting in the ammonium ion.

It's important to note that once the dative covalent bond is formed, it's no different from any other covalent bond. The shared pair of electrons is located between the two atoms, holding them together. The only difference is in how the bond was formed. This type of bonding is crucial in many chemical reactions and is a fundamental concept in understanding the structure and behaviour of molecules.