A Study of the origin of the chelate effect
Keywords:
chelate, Monodentate ligandsAbstract
A chelate is a type of ligand. A multidentate (dentate is Latin for tooth) ligand that uses more than one atom to bind to a metal in a coordination complex, The metal is the electron-pair acceptor and the chelating agent the electron-pair donor. When binding to the metal ion, the chelate (ligand) forms a ring of atoms, of which the metal is one member. The chelate complex charge exactly neutralizes the charge on the metal ion. Most rings contain >4 and <8 atom members; the most stable typically is a 5-membered ring. Bidentate describes a chelate where two atoms from the chelate complex bond to the metal and tridentate would indicate three coordinating atoms. Many chelating extractants are weak acids, therefore, control of pH is important in many extracting schemes.
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