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A brief overview of Chelates
Jul 28, 2017

Complexes with annular structures are obtained by the chelating action of a chelating ring with two or more ligands and the same metal ions. Coordination keys between ligands and metal ions usually have two types:

(1) The acid group on the ligand dissociated to H and then matched with the metal ions;

Metal EDTA Chelate
 Metal EDTA Chelate

(2) The ligand contains the neutral group of the electron pair and the metal ion.

One of the most notable properties of chelate is its thermodynamic stability and thermal stability. The stability of chelating rings is similar to that of aromatic rings. Chelate can be a neutral molecule without charge, or a charged complexing ion, the former soluble in organic solution, the latter soluble in water, which can be used to isolate and analyze metal ions. The general principle of the formation of chelate by metal ions and ligands is the theory of soft and hard acid and alkali, which is: hard and hard, soft.

The chelate of metal ions and the multiple-tooth ligands has a higher stability than that of the similar complexes produced by the single tooth ligand. This is because it is difficult to disconnect the chelating agent with two keys located on the metal. Some metal chelating agents obtained by chelation are widely used, for example, EDTA is a six-tooth chelating agent, which can be applied to water softening, food preservation and so on; the separation and analysis of alkali and alkaline earth metal by ring ligand crown ethers is particularly applicable.