Chelation

Chelation describes the bonding of the organic ligand(s) to a metal atom, forming a metal complex. A compound that avidly engages in this kind of complex formation is often called a chelating agent (for example, EDTA).

The term chelate was first applied in 1920 by Sir Gilbert T. Morgan and H.D.K. Drew in J. Chem. Soc., 1920, 117, 1456, who stated: "The adjective chelate, derived from the great claw or chela (chely- Greek) of the lobster or other crustaceans, is suggested for the caliperlike groups which function as two associating units and fasten to the central atom so as to produce heterocyclic rings."

Metal complexes are of widespread interest and studied by inorganic chemists, physical and organic chemists, biochemists, pharmacologists, molecular biologists and environmentalists.