chelate effect

Question

Chelate complexes are more stable than similar non-chelate complexes due to:

RankGuru · Accepted Answer

The **Chelate Effect** refers to the increased stability of complexes containing polydentate (chelating) ligands compared to monodentate ones.
- When a chelating ligand (like ethylenediamine) replaces two monodentate ligands (like $NH_3$):
$[M(NH_3)_2] + en \rightleftharpoons [M(en)] + 2NH_3$
- The number of particles in the solution increases (from 2 reactants to 3 products).
- This leads to an **increase in entropy** ($\Delta S > 0$), making the Gibbs free energy $\Delta G = \Delta H - T\Delta S$ more negative.
- Therefore, the chelate effect is primarily **entropy-driven**.

Rank Guru

chelate effect

Select the correct option: