What is meant by the term 'dative covalent bond'?

A dative covalent bond refers to a type of covalent bond where both electrons are provided by one 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 contributes one electron to the bond. However, in a dative covalent bond, one atom provides both electrons. This usually happens when one atom has a lone pair of electrons and the other atom is short of electrons to achieve a stable electron configuration.

The atom that donates the pair of electrons is known as the donor atom, while the atom that accepts the electrons is referred to as the acceptor atom. The dative covalent bond is represented by an arrow pointing from the donor atom to the acceptor atom.

An example of a molecule that contains a dative covalent bond is ammonia (NH3). In this molecule, the nitrogen atom has a lone pair of electrons that it can donate to form a dative covalent bond. If a hydrogen ion (H+) approaches the ammonia molecule, the nitrogen atom can donate its lone pair of electrons to form a bond with the hydrogen ion, creating the ammonium ion (NH4+).

Understanding the concept of dative covalent bonding is crucial in chemistry as it helps to explain the structure and behaviour of many molecules and ions. It is particularly important in the study of transition metal complexes and organic compounds.