• A?complex?is a molecule or ion formed by a?central metal atom?or ion?surrounded by one or more?ligands
• A ligand is a species that contains one or more?lone pairs of electrons
• The ligand forms a?dative covalent bond?with the central metal atom or ion, by donating its lone pair of electrons

Example of a complex ion formed by a central aluminium(III) ion and six water molecule ligands