The co-ordination number of cobalt in [Co(en)₂Br₂]Cl₂ is –

To form a coordination bond, one needs a ligand. Which of the following species cannot be a ligand –

The co-ordination number of a metal in co-ordination compound is –

The total number of Ligands attached to the central metal ion through coordinate bond is called –

The addition compounds, which retain their identity in solution are called –

The coordination number and oxidation number of the central metal ion in the complex [Pt(en)₂]²⁺ is