It describes the enhanced affinity of chelating ligands for a metal ion compared to the affinity of a collection of similar nonchelating (monodentate) ligands for the same metal.
And that's the key: this is an example of the chelate effect. The chelate effect is ' the enhanced stability of a complex containing chelating (i.e polydentate) ligands over one containing similar monodentate ligands '. Which in turn means that the source of the chelate effect must lie in the entropy term, TδS. Indeed when we measure the thermodynamic quantities, we can show that this is the case. If we look at the combined reaction: we find that log β = 9.67, δH° = -12.1 kJ mol -1, and-TδS° = -55.1 kJ mol -1. che•la•tion. 1. the process of chelating. 2. a. a method of removing certain heavy metals from the bloodstream, used esp. in treating lead or mercury poisoning. b. a controversial treatment for arteriosclerosis that attempts to remove calcium deposits from the inner walls of the coronary arteries. chelation. n. 1. (Chemistry) chem the process by which a chelate is formed. 2. (Zoology) animal husbandry the process by which trace elements in an animal's feed are bonded to amino acids, ensuring their absorption into the animal's body. EDTA is a chemical that binds and holds on to (chelates) minerals and metals such as chromium, iron, lead, mercury, copper, aluminum, nickel, zinc, calcium, cobalt, manganese, and magnesium. When they are bound, they can't have any effects on the body and they are removed from the body.  The chelate effect describes the enhanced affinity of chelating ligands for a metal ion compared to the affinity of a collection of similar nonchelating (monodentate) ligands for the same metal. In equation (1) there are two particles on the left and one on the right, whereas in equation (2) there are three particles on the left and one on the right. This difference means that less entropy of disorder is lost when the chelate complex is formed than when the complex with monodentate ligands is formed. The most common side effect of chelation therapy is a burning sensation at the site where the EDTA is injected into the vein. Rarely, side effects can include fever, headache, nausea, and vomiting. EDTA binds to heavy metals and minerals in the blood so that they can be excreted in the urine. Another intravenous agent used by some physicians for mercury detoxification is called DMPS (2,3-Dimercapto-1-propanesulfonic acid). The chelate effect. Sometimes we see vast differences in the values of K for reactions which on the surface appear remarkably similar. For example: Since these figures are logs, what this means is that [Ni(en) 3 ] 2+ is 10 10 times more stable than [Ni(NH 3) 6 ] 2+ . Which in turn means that the source of the chelate effect must lie in the entropy term, TδS. Indeed when we measure the thermodynamic quantities, we can show that this is the case. If we look at the combined reaction: we find that log β = 9.67, δH° = -12.1 kJ mol -1, and-TδS° = -55.1 kJ mol -1. Chelation therapy is a treatment that involves repeated intravenous (IV) administration of a chemical solution of ethylenediaminetetraacetic acid, or EDTA. It is used to treat acute and chronic lead poisoning by pulling toxins (including heavy metals such as lead, cadmium, and mercury) from the bloodstream. The dose depends on the amount of lead in the child's blood, as well as the child's height and weight. Daily treatment for up to 5 days may be required. Adult. For heavy metal toxicity: EDTA chelation therapy is often given intravenously with calcium, magnesium, and vitamins B and C over a period of 1 to 3 hours. The recommended adult dosage varies depending on the size of the person and the amount of lead or other metal in the body Chelation therapy is a medical procedure that involves the administration of chelating agents to remove heavy metals from the body. According to the findings of a 1997 systematic review, EDTA chelation therapy is not effective as a treatment for coronary artery disease and this use is not approved in the United States by the US Food and Drug Administration (FDA). Chelation (pronounced key-LAY-shun) therapy is treatment used in conventional medicine for removing heavy metals (including mercury) from the blood. It involves intravenous injections of a chelating agent, EDTA (ethylene diamine tetra-acetic acid), a synthetic amino acid. EDTA binds to heavy metals and minerals in the blood so that they can be excreted in the urine. Another intravenous agent used by some physicians for mercury detoxification is called DMPS (2,3-Dimercapto-1-propanesulfonic acid).
http://mjmorris.staff.shef.ac.uk/teaching/CHM1002/lect5c.html http://www.thefreedictionary.com/Chelate+Effect http://www.webmd.com/vitamins-supplements/ingredientmono-1032-EDTA.aspx?activeIngredientId=1032&activeIngredientName=EDTA https://en.wikipedia.org/wiki/Chelation http://www.drweil.com/drw/u/ART03408/Chelation-Therapy.html http://mjmorris.staff.shef.ac.uk/teaching/CHM1002/lect5c.html http://umm.edu/health/medical/altmed/supplement/ethylenediaminetetraacetic-acid https://en.wikipedia.org/wiki/Chelation_therapy http://www.drweil.com/drw/u/ART03408/Chelation-Therapy.html
what is chelating effect