Hello, reders welcome to chemwhite.com today i am going to example about chelate effect and their examples.

What is chelate effect?

Development of stability of an matel when the ligands are attached to the matel. and due to this development of the formation of chelate ring in matel by polydendate ligands in known as chelete effect. and this type of formation of chelete ring gives more stability for matel.

for examples,

[CO (en) 6]3+ – More stability (one or more chelate ring) but

[CO (NH3)6]3+ – less stability (without chelate ring)

So, we can say that, the coordinate compound or complex containing chelete ring is really more stable compair with without chelete ring.


When Polydentate ligand attached in the central metals atom, making a closed or ring structure. this phenomenon is called chelation.


Condition of chelation

When the complex is formed in a chelation form complex should be have following conditions.

  1. Complex should be at least Polydentate ligand. which make closer or ring type structure around the center metal atoms.
  2. Central metals atoms must required two Or more positive oxidation state.
  3. Chelete ring must be stabilized the complex.

Chelete ligands

When the ligand are attached in the central matel atohis is known as chelete ligands. You can understand properly with examples,

We can see that central matel atom (Cu)2+ are attached to ligands. and this attachment is known as chelete ligands. and this hole complex is know as chelete.

Chelate ring

When ligands bind to the central metal ion, it forms ring of atoms. or When ligands are attached (bind) to the central metal ions, they form chelete ring of atoms. this chelete ring give more stability. Most of chelete ring contain >4 and <8 atom members. To determine the number of chelete ring when the ligand bind with the central metal.

Differance between monodentate ligands and chelating ligands

Monodentate ligands – the best example for monodentate ligads is,

Chelating ligands – chelete ligands is like ethylenediamine. In this case it form five or six membered ring. but chelete complex are more stable then the analogous complex with monodentate ligands.

for examples,


What are the fector effecting stability of complexes?

  1. Size of ring
  2. Matter chelete showing 5 mamber ring are more stable and chelete having 6 mamber ring are slightly less stable.
  3. 6 mamber chelete having unsaturation are more stable then 5 mamber chelete.
  4. Ring of other sizes grater then 6 are none. but these are unstable and show little chelete effect. reson is bulkiness. It mean it give little chelete.
  5. No of chelete ring – no of chelete ring increase stability of complex increase.

Steric effect

The steric effect is also significant in the stability. If the stability of chelete complex decrease then the steric fector increase.

The steric fector effect of complex depend upon on the bulkyness of ligands.

The complex with 2 methyl B hydroxy quinolene is less stable then B hydroxy quinolene. reson is bulkyness , it persent very near to donor atom.

for examples,

(N) atom

You can see, N atom is very near to donor atom, that is the reson it is bulkyness.

Application of chelete complex in chemistry

  1. It is used nickel DMG formation. it is a chelete complex. this complex give red ppt. it is confirmative test of Ni.
  2. Mg, Al, Zn is the give ppt. with B hydroxy quinolene. this complex appear specific colour.
  3. According to biological Science, – Vitamin B12 is a chelete complex of cobalt. Cytochroms which are electron carrier are iron chelete. Plastocyanin which are also electron carrier.


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