Question

What is a Coordination Site?

Answer 1

Coordination compound:

1. In a Coordination complex or a compound there is a central metal that is surrounded by many ligands.
2. The ligands are bonded with a central metal with a coordinate bond. Therefore, the metal attaches to the ligand at a particular site called a coordination site.
3. In other words we can say that the ligand's binding sites are called coordination sites of that ligand.

Based on coordination sites (binding sites) ligand can be divided into 5 types:

1. Monodendrate ligand: Ligand has only one binding or coordination site. Eg, $F^{\mathit{-}}$,$C{l}^{\mathit{-}}$,etc.
2. Bidendrate ligand: Ligand has two coordination sites. Eg, Ethylenediamine(en),oxalate ion(ox).
3. Tridendrate ligand: Ligand has three coordination sites. Eg, Diethyenetriamine(dien).
4. Tetradendrate ligand: Ligand has four coordination sites. Eg, Triethyenetetraamine(trien).
5. Penta or polydentate ligand: Ligand having five or more than five coordination sites. Eg, Ethylenediamine tetraacetate(EDTA).