Question

Denticity is the number of ligating groups in a multidentate. State whether the state is true or false.

Answer 1

Hint: To solve this we must know the term denticity. The denticity is a term related to the constituent molecules present in a coordination compound. Denticity gives the number of donor atoms in a molecule. The word denticity is derived from Latin word ‘dentist’ meaning tooth.

Complete answer:
> We know that in coordination compounds, ligands are molecules or atoms or ions that are attached to the central metal atom. The ligands are attached to the central metal atom by chemical bonds.
> Denticity is thus defined as the number of donor atoms through which a ligand attaches to the central metal atom. The denticity of any ligand can be determined by finding the coordination number of the complex towards a common transition element and inner transition element. Denticity gives the number of donor atoms in a molecule.
> Ligands are classified as: 1 Monodentate ligands, 2. Bidentate ligands and 3. Multidentate or polydentate ligands.
- Monodentate ligands: These ligands are attached to the central metal atom by only one donor atom. Example: Ammonia which has one donor atom.
- Bidentate ligands: These ligands are attached to the central metal atom by two donor atoms. Example: Ethylenediamine which has two donor atoms.
- Multidentate ligands: These ligands are attached to the central metal atom by more than two donor atoms. Example: EDTA (Ethylenediamine tetraacetate) which gas six donor atoms.
> Thus, the statement ‘denticity is the number of ligating groups in a multidentate’ is true.

Thus, the answer is true.

Note: The denticity of a ligand affects the stability of the metal ion complex. Ligands having high denticity form more stable complexes than the ligands having low denticity. This phenomenon is known as chelate effect. Most of the chelating compounds form ring-like structures.