What is meant by the chelate effect? Give and example.

Explanation

Whe a didentate or a polydentate ligand contains donor atoms positioned in such a way that when they coordinate with the central metal ion, a five or a six membered ring is formed, the effect is called chelate effect. As a result, the stability of the complex increases. For example, the complex of `Ni^(2+)` with en is more stable than with `NH_(3)`
`Ni^(2+)(aq)+6NH_(3)(aq)iff[Ni(NH_(3))_(6)]^(2+),logbeta=8.61`
`Ni^(2+)(aq)+3en(aq)iff[Ni(en)_(3)]^(2+), log beta=18.28`
Another example of chelation and stability is given below :