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Added chelation in plants and micro-organisms. Chemists should dig up references for the other bits. Miikka Raninen 19:38, 27 November 2005 (UTC)

Sequestering same as chelating?[edit]

I believe so, so I'm adding it. --Rajah 01:19, 9 July 2006 (UTC)

Kind of. But sequestering is generally, to my knowlege, regarded as binding to a substance to take it 'out of circulation' whereas chelation is generally regarded as 'binding to a substance to enable its removal from a biological or physical system' - at least within biological systems (different criteria may apply to physical systems). To illustrate in the body, 'transferritin' sequesters iron in the blood stream when necessary (principally during times of infection) as iron is necessary for bacterial reproduction - but does not enable it's excretion, merely takes it out of circulation in its bioavailable form to inhibit its use by bacteria (pretty clever stuff). EDTA as a chelation agent binds to various ions such as some heavy metals to specifically enable their removal from the body, whether through kidney filtration or via other pathways. Does that make sense? Now I am neither a biochemist, nor a physical chemist, so will stand corrected! But that's my understanding. Antoniolus —Preceding unsigned comment added by (talk) 08:28, 8 November 2008 (UTC)

Merging with Chelate effect[edit]

I support the merger (hardly anything links here anyway). --Dirk Beetstra T C 22:53, 17 July 2006 (UTC)

Yeah, I think someone was working on missing articles, but didn't search hard enough to realize this one wasn't missing after all. —Keenan Pepper 22:58, 17 July 2006 (UTC)

I also think they should be merged.


I agree. The merge seems sensible. -mc043

Agree, merge. Dieter Simon 00:05, 16 August 2006 (UTC)

OOps .. forgot to tell, I already merged all the articles together (chelate effect, chelation, chelant, etc). All is now 'here'. --Dirk Beetstra T C 07:07, 16 August 2006 (UTC)

Important addition to the definition: it should emphasize that a single bond does not form a chelate -- this term is generally reserved for two or more bonds, of any type, between the chelating agent and the metal ion. Axewiki 15:05, 28 September 2006 (UTC)

section 'uses - nutrition' seems very non-factual[edit]

Right now,it says this:

In nutrition, certain amino acids are utilized as chelating agents to replicate the natural mineral forms found in raw fruits, vegetables, and grains. The resultant chelated minerals are absorbed directly into the bloodstream through the intestinal villi in relatively high proportions. Because micromineral levels in farm soils tend to gradually decline over the years, and because modern food processing often breaks the chelate bond and renders any remaining minerals much less bioavailable, humans today receive reduced quantities of minerals from their meals[verification needed]. Dozens of medical studies have shown that dietary supplementation with both vitamins and chelated minerals can have wide-ranging benefits to health, mental acuity, and life expectancy[verification needed]. Chelated minerals are sometimes prescribed by doctors to treat such ailments as anemia, arthritis, diabetes, nervous disorders, and heart attacks[verification needed].

Fortunately it already says 'verification needed' but the whole section is less-than-factual in tone.
micromineral levels in farm soils tend to gradually decline over the years - this is what soil fertilizer is for, right? (non-nutrition sidenote: There's a serious environmental issue with overmineralization of soil, due to excess supply with dung from intensive farming. This lead to obligatory registration, for farms in Europe, of their total mineral input and output.)
modern food processing often breaks the chelate bond - I actually came to this article after reading some concerns about artificial chelate agents such as EDTA being used as additives!! Seems there's very opposing concerns.
humans today receive reduced quantities of minerals from their meals - source badly needed.
Dozens of medical studies have shown - - source badly needed. wording very non-factual
The nutritional claims should IMHO refer to the wiki article on Dietary mineral. Whether the minerals used in mineral supplements are usually administered in the form of chelates,is relevant but needs verification.
Chelated minerals are sometimes prescribed by doctors - it is important to note that Chelation Therapy , (linked in 'see also') , is actually about administering chelating agents to remove excess minerals, not about medical use of chelated minerals. Is there any source or article supporting these medical claims on the use of chelated minerals, other than anything being said in Dietary mineral ?
-- 09:17, 21 October 2006 (UTC)

Saw a video about chelation on You-Tube / Google Videos “Heavy Metals Detox & Chelation Therapy - Austin Wellness". The chiropractic doctor said that metal elements if taken orally would have only a very minute / small absorption into the blood stream, and to achieve higher bioavailability / absorption, those same metal elements had to be combined with a protein to permit absorption during digestion. These ameno acids / proteins are termed chelates after they have been combined with these intended metal elements like calcium, magnesium, etc. See the following search and pick which one is a WP:RS for your tastes. Oldspammer (talk) 13:14, 23 July 2009 (UTC)

TV Show 15 to 20 Yeas Ago[edit]

I recall seeing a talk show on Canadian TV. It had one host, and multiple guests. The show was about anti-aging or something.

It stuck with me that one of the guests explained that hardening of the arteries (atherosclerosis) involved a calcification process of the blood vessel walls, and that Calcium was a metal. Even back then the guest stated that it was very difficult to locate a doctor who would administer chelation therapy to reduce the calcification of a patient's circulatory system to fix heart disease or poor circulation troubles.

He explained that the chelation therapy treatment had no horrendous side-effects, since, after all, it was already being used as a safe, effective treatment method for heavy metal poisoning. It was extremely frustrating and puzzling to him how illogical the American Medical Association (AMA) treated this practice issue. Most doctors would refuse to treat atherosclerosis using chelation therapy because it was not a listed protocol for its treatment. Using a protocol not listed as standard operating procedure for a given disease is grounds for medical malpractice. As such doctors who are timid about lawsuits or worse, losing their license to practice medicine are forced to comply with the established protocols of surgery or administering drug therapy instead.

The TV guest listed several US states where some doctors could be eventually found to prescribe this treatment without it being a case of heavy metal poisoning. He explained also that even those friendly doctors did not want to use the procedure very often on the same patient. He explained that calcium was added back in order to reduce thinning of bone. He also explained that the post-treatment adding back of calcium and other vitamins and minerals done to prevent unnecessary losses of this nature, made patients "feel" great as much if not more so than had they only just been treated with the chelating agent. The patients so treated, the guest claimed remarkably, would have virtually all of their heavy plaque deposits stripped away, leaving their blood vessels / heart / valves free to operate almost as effectively as a young healthy athlete.

He or another guest were also heavily endorsing anti-oxidants. I seem to recall that it was folic acid--and that several vegetables and plants were mentioned that contained this substance.

Ketosis and ketones were also explained.

From chemistry I seem to remember that Calcium is a fairly reactive metal, and that trying to chelate it might be a tough job so that any agent used to grab it might easily grab other less reactive metals from one's system. It is not quite as reactive as sodium, but quite nasty if not found in ionic solution or in salt form.

In the TV show, to my recollection of it now, did not have any specifics about the chelating agent used for the atherosclerosis treatment. From the description of the various chelating agents listed, specifically that different agents more specifically target certain metals, then calcium as a highly reactive metal would be more troublesome to specifically chelate. If a double-blind study were used with inappropriate chelating agents being used, the conclusions would be forgone that failure would be the outcome of such an exercise: ie., chelating is no more effective than placebo--which would be inaccurate and biased. Oldspammer 18:16, 27 May 2007 (UTC)

In researching Alzheimer's disease, I found a treatment scheme based on chelation meant to cure Alzheimer's disease after numerous treatments. I compiled an article from several web sources, then today was re-reading the document. I performed a search on one of the doctors mentioned in the article, and found an audio recording of this doctor. It specifically states that chelation was found effective when it was first discovered in the early 1900s and used on car battery factory workers who also had heart disease and chest pains. The key chemical involved was developed a decade or more before WW2, and the German manufacturer had begun in the late 1920s - early 1930s to ship the compound world-wide when WW2 broke out. The interviewed doctor also says that the AMA are money hungry for their surgeon doctor members and hospitals. It also states that a Swiss study demonstrated a 90% preventative effect on cancer. If I were evil and greedy, then I would fight to prevent chelation therapy from competing with my surgical livelihood, have false medical treatment studies published in peer reviewed journals, have the practice banned from use, sue and take away the licenses of doctors performing the procedure just like some in the USA, and similar countries have done. Does it seems simple to structure a double blind study to fail: use too much, or use to little, or mix in something that will conflict, or summarize incorrectly, or tamper with the results provided by other contributing researchers? Who benefits from preventing chelation therapy? Heart and stroke foundation? Cancer societies? Pharma? Universities funded by the same? Hmmm? Oldspammer (talk) 23:35, 17 April 2008 (UTC)
Here here Oldspammer! Ah a little intelligence brought to the discussion at last. Good on you - hope someone picks up the ball. This is not about conspiracy you all, unless you choose to call it that to bury your heads in the sand, it is about economic reality. Big Pharma has share holders, and cares first and foremost about dividends and profits - health doesn't come into the question - just the game that they play in. Just lest we forget it wasn't many decades ago that smoking was endorsed by doctors and dentists - for health benefits. I'll be back ... Antoniolus —Preceding unsigned comment added by (talk) 08:05, 8 November 2008 (UTC)

Chelation is also used...for autism[edit]

"...Autistic individuals generally reject this treatment for being unnecessary..." Somehow this seems to beg the question, how far autistic people are able to judge and therefore determine their treatment and it being necessary or not. Should this be rephrased? Surely it should read "carers" or "people in charge of their care" (who reject this treatment)? Dieter Simon 23:06, 4 July 2007 (UTC)

Your statement implies that autistic people are unable to reason or think for themselves, which could not be further from the truth. Pw33n (talk) 00:17, 12 November 2008 (UTC)
There is considerable research out there on this subject - not just for autism but also for heavy metal detox generally. This section is a little weak. Antoniolus —Preceding unsigned comment added by (talk) 07:59, 8 November 2008 (UTC)

I am very offended. I am on the autistic spectrum and am studying at a top 10 UK university, living without a carer etc. Autism is not Down's Syndrome or any such condition, many people may posess a mild form of Autism without you realising, such as Aspergers etc.

You are clearly ignorant of the condition in its many forms and would benefit from looking up the article regarding the condition on Wikipedia.  —Preceding unsigned comment added by (talk) 10:07, 6 April 2010 (UTC) 

Fix pronunciation[edit]

I don't know IPA. Pronunciation is key-lation, not chee-lation. Cburnett 05:13, 9 July 2007 (UTC)

 Done - Zeibura (Talk) 20:50, 11 July 2007 (UTC)
Shouldn't the pronunciation, etymology and wikt-link be in the first paragraph? The claw analogy makes the actual mechanism much more tangible than just saying two or more separate bindings.-- (talk) 06:09, 5 December 2009 (UTC)
The etymology is usually placed in the introduction, except when it is too long. I agree the etymology is very clarifying. The pronunciation is not part of it.--Wickey-nl (talk) 14:07, 5 December 2009 (UTC)

Define "Chelate Effect"[edit]

In the "The Chelate Effect" section, there is no definition of the chelate effect. That effect is defined and described more clearly though less technically at . Cowboyjo (talk) 17:10, 29 August 2009 (UTC)

I tried to address the query.--Smokefoot (talk) 23:29, 29 August 2009 (UTC)

Semi-randome factoid table removed from article on Aug, 2009[edit]

The following section was removed from the text since it seems to be a collection site for semi-randomly selected ligands. The list could go on forever (which I realized when seeing hydrolyzed wool). So we need to come up with a more focused set of chelating agents or drop this idea. Not a really big deal to me.--Smokefoot (talk) 23:29, 29 August 2009 (UTC)

Chelants of various technologies[edit]

Radio-isotope chelation[edit]

Quoting from "Responding to the Radiation Threat" :

" Since the biochemical properties of plutonium(IV) and iron(III) are similar, we modeled our sequestering agents after the chelating unit found in siderophores," Raymond says. Siderophores are small molecules secreted by bacteria to extract and solubilize iron. "This biomimetic approach enabled us to design multidentate hydroxypyridonate ligands that are unrivaled in terms of actinide-affinity, selectivity and efficiency.

The two best candidate hydroxypyridonate ligands -- nicknamed HOPO -- developed by Abergel and her colleagues are a tetradentate, which has four chelating arms, and an octadentate, which has eight chelating arms. The "arms" in this case are atoms with pairs of electrons available for covalent bonding with an actinide. "

Responding to the Radiation Threat from from ScienceDaily

Consider appending?

A lot of literature exists on the topic of siderophore-inspired ligands for Pu and other actinides. A review or book rather than a specialized article, would be a useful addition.--Smokefoot (talk) 13:50, 7 March 2012 (UTC)

Complexing in General and Clathrate Vs. Chelate Complexes[edit]

As I read this article, there is mention of citric acid (probably intending partly or fully ionized citrates) as a chelating agent for metal ions. I don't believe citrate fits the definition of chelation, but is one of a number of substances that form relatively stable complexes, some of them clathrate, without being chelates. In the case of partly ionized citrate, it is possible that some coordination bonds form, but usually hydrogen is displaced as an ion by the metal in the functioning of citrate in complexing.

I have also read that Hueckel's Rule is important in determining the stability of a chelate complex, i.e. the formation of one or more rings satisfying Hueckel's Rule by the substance being chelated. (talk) 13:49, 2 August 2012 (UTC)

Too technical for general readers[edit]

I am adding {{Technical}}, because this article is much too technical for general readers to get any value from at all. The lead section, at least, should provide some basic understanding of what chelation is to a total layman, a person who has no understanding of chemistry but has heard the word and would like a somewhat better understanding of what it is than a dictionary affords—but to whom words like monodentate, polydentate and ligand might as well be Greek (and to whom "multiple bonded", the current gloss for polydentate, means no more than polydentate does).

Packing the article—again, especially the lead section—with links to other articles (which very likely will be no less technical than this one is) is a very poor substitute for using less technical jargon. The reader should be able to read the lead section without having to jump to any other articles to get a basic understanding of the subject.

A good starting point in fixing this serious defect might be to take every linked term in the lead section and replace it with a term (or a sentence) that would require no link for a below-average high school student to understand. That below-average high school student is very likely to be exactly the kind of reader who comes most often to this article, and its lead section should help, not confuse that student.

Anyone who can understand this article as it is now doesn't need this article.--Jim10701 (talk) 23:43, 26 December 2012 (UTC)

Jim, there is merit to your remarks, from which response you may deduce that I did not write the original. However, matters are not as simple as you may expect as a corollary. For one thing, to accommodate the typical below-average high school student would be rather ambitious for a topic of this nature. In fact, I think that for most of the article, most of what it says, even if gently massaged to rephrase it to a level suited to University-level chemistry 101, probably would rob it of meaning; the underlying concepts are themselves non-trivial, which is the death of fundamental simplification.
There is of course another approach, namely to butcher the material till only hand-waving remains, leaving the reader with a comfortable feeling of having understood, without inconsiderately burdening him with substance. In practice in my opinion what one needs is both approaches: the lead should be practically pure layman's speech, without enough information overload to scare anyone off, but with enough substance to invite the chemically literate to keep reading. It should be followed by a separate introductory section in greater detail, but couched in similar scientific baby-talk, giving sufficient detail to reward youngsters and laymen who actually had hoped to learn something. Subsequent sections could continue as literately as possible, but without compromising the technical content.
Now, here is where things become tricky. Chelation is not a subject that is much dealt with by citable literature at that level of register, which means that trying to find things to say verifiably becomes verrry problematic. All the same, though I am not a professional chemist, I would not greatly hesitate to produce something of the kind myself, but there is a problem, a veritable Apollyon on the way: such material would be very hard to cite, and extremely hard, if at all possible, to word without synthesis. I don't mind working at it, but not if there is going to be no point, with all the wiki lawyers descending with glad cries to feed and destroy (I did not choose the Apollyon metaphor idly).
So, bearing in mind that I detest and hold in contempt most of the rules associated with or referrable to the pillars of Wikipedia, I still am not inclined to waste my substance on futile effort, however well intentioned. If you have any suggestions and are willing to stay the course in the event that we produce something worthwhile, then by all means come back and tell me all about it so that I may reconsider. Until then, have good days ;-) JonRichfield (talk) 12:44, 27 December 2012 (UTC)

An introductory paragraph[edit]

This article sorely misses an opener describing chelation in general terms for the average encyclopedia reader, before plunging into the essential chemistry involved.--Wetman (talk) 13:23, 7 March 2013 (UTC)

Thank you for taking the time to deal with this issue. It is important to try to translate the tech talk. So take a stab at revising and other more chemical editors can tweak your phrasing for technical accuracy. Chelation is an inherently chemical topic, so I am baffled how to make this topic more accessible. --Smokefoot (talk) 13:39, 7 March 2013 (UTC)

In the first paragraph it says "Involves two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central atom" - should this say ion rather than atom? KStar777 (talk) 10:37, 16 June 2017 (UTC)

Bind vs bond[edit]

Re the statement " ... particular way that ions and molecules bond to metal ions". My suggestion is that chelation is not about bonding (single, double, triple and covalent ionic etc). It is about the points of attachment. For this reason, I had suggested the term bind" over "bond". EDTA is rather ionic in its bonding, cod of course involves a lot of pi-bonding (with double bond character). So the bonding theme can get rather involved. --Smokefoot (talk) 16:07, 26 December 2015 (UTC)

I concur that "bind" is a better term than "bond", and metal ions are not necessarily involved - See [Ni(cod)2] as an example. EdChem (talk) 16:19, 26 December 2015 (UTC)

Heavy metal detoxification[edit]

Perhaps we should mention that chelation can also be used to remove heavy metals from rivers, ...[1] KVDP (talk) 13:42, 5 December 2016 (UTC)

Probably not. Chelation removes, when it works right, metal ions from a solution. It matters not whether the solution is a river, an ocean, or a sample in a test tube. --Smokefoot (talk) 13:52, 5 December 2016 (UTC)
The use of chelation in environmental remediation (not just rivers) seems like a notable application that is worth mentioning in this article. There are plenty of secondary sources available that could support such content. A few seconds on Google turns up several examples, such as this book chapter Use of Chelating Agents for Remediation of Heavy Metal Contaminated Soil and this review The use of chelating agents in the remediation of metal-contaminated soils: a review. Deli nk (talk) 16:19, 5 December 2016 (UTC)
Those reviews indeed seem to be promising sources. Thank you Deli.--Smokefoot (talk) 19:05, 5 December 2016 (UTC)


Requesting subsection on applications in retting[edit]

On the page for bast fibre ( it mentions that chelating agents can be used for retting. I am not nearly knowledgeable enough to add any information about this but a small section on how and why this is sometimes done instead of traditional retting techniques would be a good addition. Alternatively (or, additionally) a section about chemical retting on the retting page ( would also be a good addition.

The challenge in addressing your request is that that chelating agents are ill-defined (proteins, humic acid) and pervasive. Virtually all biomaterials (biomass, mineral surfaces) exhibit chelating properties. Also the claim in the article Bast_fibre reads like hearsay. Sorry to sound so negative. If you find other chemical problems in the articles on fibers, let me know. Some of these articles are old, written based on a combination of knowledge and wishful thinking, and probably merit reexamination.--Smokefoot (talk) 23:55, 26 July 2017 (UTC)