[vikram]

Which has better chelating ability out of Urea,Citric acid and glycine?

Thank you:)

[AWK]

Complexes of urea are generally weak.
For other two chelators there are no simple answer.

[wildfyr]

My gut says citric acid is best but I have nothing to back that up.

[Babcock_Hall]

Which has better chelating ability out of Urea,Citric acid and glycine?

Thank you:)

What are your thoughts?  It is a forum rule that you start by giving your answer or your thoughts.  My suggestion is that you start by asking yourself what the definition of the chelate effect is.

[AWK]

Find data. You can finf it through google.

[phth]

citric acid is the best because it is tridentate, so it takes 3x as much dissociation as a mono dentate tricarboxylate ligand or 1.5x as much work to remove as a bidentate ligand...

[Arkcon]

After all these posts, could the O.P. be troubled to tell us what ion they're trying to chelate?  It does matter.  For example, nickel and iron have a very high affinity for citrate.  But maybe other ions form stronger complexes with the other chleators.

[vikram]

Thank you for your suggestions.I posted this on behalf of my friend.He want to know its chelating ability towards Al³⁺ ion.

Even I believe citric acid would be the best. But It's just an intuition as I don't have any supporting document.

[AWK]

The strongest chelator properties for Al³⁺ show EDTA and salicylic acid, citric and oxalic acid (a bit less than citric acid).

http://www.coldcure.com/html/stability_constants.html