What is the complex Ions for CuO

The ion or molecule that forms the bond with the transition metal is called a ligand, e. g. : Cl-, : CN-, H2O:, : NH3. More than one ligand can bind to a transition metal ion to form a complex ion. The copper ion, Cu2 + (aq), in aqueous solution, forms a blue complex ion, [Cu (OH2) 6]2+, with 6 water molecules.