Talk:Radical (chemistry)

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A serious ommssion[edit]

Any article on radicals that does not list the common inorganic radicals and give their chemical formulas has a serious lacking. After all, the Wikipedia is supposed to be written for the General Reader, and not for chemists (and not for other experts in other fields).
Someone needs to explain something about these: borates, carbonates, nitrates, nitrites, hydroxides, peroxides, phosphates, sulfites, sulfates, chlorites, chlorates, perchlorates, chromates, permanganates, bromates, and iodates. (talk) 01:11, 28 April 2012 (UTC)

Information on these is available. I don't think any of them are radical. --SmokeyJoe (talk) 23:57, 25 August 2015 (UTC)

Wording in summary is very unclear[edit]

"are atoms, molecules, or ions with unpaired electrons on an otherwise open shell configuration. These unpaired electrons" I would like to note that this phrase indicates that both the free electron, and the nucleus are both free radicles. this is inaccurate. --Christopherlee247 (talk) 15:55, 5 November 2009 (UTC)

Not sure what he is getting at, but I do believe the free electron can be trivially considered a radical. e- or H2O- would be radical. H+, the free proton, the free hydrogen nucleus, is not radical. "with unpaired electrons" is a pretty good starting definition for a radical. --SmokeyJoe (talk) 00:04, 26 August 2015 (UTC)


excuse me there...I have an assignment about acid radicals and i tried to search for it on the wikipedia but all i could find was radicals as a whole...I'd be pleased if anyone could add some information about it...or even send me any article that explains exactly what are the acid radicals..thank you please contact : —Preceding unsigned comment added by (talk) 13:54, 19 October 2007 (UTC)

So, how did your assignment go? ;-) (talk) 10:59, 8 August 2013 (UTC)

Ability to understandthe article[edit]

I hope you take this to be constuctive and friendly criticism, but i found the article very hard to understand, perhaps others feel the same. Its obvious the author(s) of this article spent a great deal of time and effort to write the article. Could it be put more into "laymans" terms to help other appreciate the subject more?

Thanks and best wishes

I changed to to combaine what was on Radical (chemistry) and Free Radical and formated it. They should be merged, forwarding Free radical to here. Zwa 03:18, 24 Jun 2005 (UTC)

This page isn't particularly well organised/explained, insomuch as it talks about two different meanings of the word radical in chemistry. It would seem better to me to have a disambiguation page for this with a link to the exsisting Free radical page which is far more comprehensive, and another to a slightly expanded page explaining the use of the word in the sense of a substituent. --ChemRad 23:53, 22 Feb 2005 (UTC) acid radicals are of two types.dilute and concentrated acid free radicals. —Preceding unsigned comment added by (talk) 23:31, 24 August 2009 (UTC)

== vote for merge wir species

I'm not a chemist, but I've never heard of an atomic or molecular species before. If there is such a thing in chemistry, it should be linked to definition. If not, then that's some bad word choice.

It is clear that you are not a chemist then. "atomic or molecular species" is a very commonly used term in chemistry.

Are radicals always uncharged?[edit]

I think it is untrue to suggest that radicals are uncharged. Radicals can be charged.

The "uncharged" has got to go. Superoxide is both an anion and a free radical, the charge is irrelevant. Jasoninkid

Observational Database?[edit]

A large observational database of many different atmospheric constituents including radicals from a host of platforms is available. It is of general use. Do you think it should be added to the article text? Dlary

improper referrals[edit]

1st refference must be P78... great link btw. —Preceding unsigned comment added by (talk) 13:19, 11 January 2011 (UTC)

The section titled "Elimination of systemic free radicals" contains the sentence "Since reactive oxidative species (ROS) like sunlight and carcinogens lead to the formation of free radicals, inhibition of free radicals therefore decreases the risk of tumoric growth." Sunlight is certainly not a free radical and not all carcinogens are either. This sentence makes no logical sense and should be re-written by the author to better express their argument. 23:47, 10 March 2007 (UTC)

There are so many errors in this pare it should just be dieted. Jasoninkid


If memory serves Spin Traps are usually used in EPR experiments with free radicals should a part be written on them? Jasoninkid

Probably, but radical symbols are often not used. They are not necessary, being implied by the chemical structure, and are usually only included for emphasis. --SmokeyJoe (talk) 00:06, 26 August 2015 (UTC)


Free radicals do not half to be created from a broken covalent bond, although they can, they can also be made by one e- reduction or oxidation of a atom or molecule, this line needs to be fixed. Jasoninkid

What is this obsession with no charge, "all species" should be most at most. Jasoninkid

They can also be created by a single electron being knocked out of an atom or molecule by high energy collisions (eg: cosmic rays). -- (talk) 16:41, 22 February 2008 (UTC)


O2 is not a radical. Jasoninkid

O2 is a radical, the MO diagram shows two unpaired electrons, hence O2 is paramagnetic. —Preceding unsigned comment added by (talk) 11:41, 16 November 2007 (UTC)

Diradical is a more descriptive term, but this only applies to species where there are two unpaired electrons in degenerate orbitals. Both the 3Σg- paramagnetic and 1Σg+ diamagnetic states of O2 (i.e. what are commonly referred to as triplet and singlet dioxygen) are diradicals. The remaining non-aufbau singlet is not a diradical. This said, O2 is not a biradical as the unpaired electrons are not localised to spatially seperate centres. Eutactic (talk) 03:46, 27 August 2009 (UTC)

loose definition[edit]

Jasoninkid wrote many suggestion about what is radicals. I think there are two definition of radical. From the GLOSSARY OF TERMS USED IN PHYSICAL ORGANIC CHEMISTRY (IUPAC Recommendations 1994)[1] radicals are molecules which have unpaired electron. On the other hand, according to recent trend at some fierld of chemistry, definition of radical contains the any chemically unstable molecules such as singlet state of biradical, ion and so on. I added about this in the section of "Loose definition of radicals" this article. Please read and develop it.--Jingxin 01:26, 19 April 2007 (UTC)

New "Free radical reaction" article needed[edit]

Free radical reaction needs to be created; free-radical reactions are a huge topic in chemistry; selectivity, homolysis and soforth is huge. 09:16, 24 April 2007 (UTC)

Can someone please check the image supplied in the first paragraph? It looks incorrect... 11:27, 24 April 2007 (UTC)
The same question was already posted on commons:Image talk:Radical.svg. See answer on commons. Annabel 18:07, 25 April 2007 (UTC)

this is not to be a good article for radicals —Preceding unsigned comment added by (talk) 05:03, 2 September 2007 (UTC)

Stop this confusion please[edit]

I have published several articles of original research in peer reviewed journals concerning oxygen free radicles.

These are not the same as side chain radicles attached to organic compounds.

This web page confuses the two, a criticism [see above] which is correct

There should be two separate sites. One dealing with organic side chains [radicles], the othe dealing with oxygen free radicles Historygypsy (talk) 23:35, 5 August 2008 (UTC)

Various edits for clarity[edit]

Have extensively edited the page for clarity, syntax, etc. without changing the sense. Bigbuck (talk) 19:09, 15 February 2012 (UTC)

What the hell is "verdazys" mentioned under Persistent radicals?[edit]

I'm a chemist yet not a specialist but i never heard of this term. A little search on the net didn't bring any answers, just copies of the sentence on Wikipedia. Can anyone please explain what verdazys is and if not, it's probably a hoax and should be removed. The real bicky (talk) 10:09, 8 May 2012 (UTC)

O2 is not a radical[edit]

I went back and checked, it was that added this heading. The oxygen molecule is, in fact a diradical species, at least in its ground state, which is known as triplet oxygen. This means O2 is usually better represented as ·O-O·, rather than O=O. This triplet state is relatively unreactive, and O2 must be excited to the singlet state in order to take part in combustion. This is the reason, I believe why we aren't all on fire right now. - Tomásdearg92 (talk) 22:51, 29 January 2013 (UTC)

Ah, just saw that this has been covered above (in the section 'combustion') by someone with a better, more rigourous knowledge of the subject. - Tomásdearg92 (talk) 22:54, 29 January 2013 (UTC)

Confusion with ions?[edit]

The following sentence, temporarily removed from the head section, seems to confuse "radicals" with "ions":

Free radicals may have positive, negative, or zero charge. [...]Ionizing radiation can create free radicals. The ionization process pushes an electron out of its orbit around an atomic nucleus causing the formation of electrical charges on atoms or molecules. If the free electron strikes a water molecule, the ionized molecule will produce a free radical.[1]

Sure, a molecule can be a radical and also have nonzero charge; but the two concepts are independent, and ions like CO2−
or NH+
are not considered "radicals" (are they?)
Those two sentences are not quite wrong, but they will probably confuse the reader, especially if they are in the first paragraph of the article. --Jorge Stolfi (talk) 17:01, 29 January 2013 (UTC)

I think the sentence should just be reworded in a more careful manner. Maybe the emphasis should be that the ionising radiation causes the formation of free radicals through the ejection of single, unpaired electrons, which can react to produce further free radicals, as opposed to the production of a charged species. - Tomásdearg92 (talk) 23:09, 29 January 2013 (UTC)
OK, will do. --Jorge Stolfi (talk) 23:59, 29 January 2013 (UTC)
  1. ^ "What Is Ionizing Radiation?". Retrieved 2012-12-05. 

Is there a not-so-loose definition?[edit]

The head section gives only the strict definition of "radical" that requires "unpaired electrons in an open shell". By this definition I would think that free methylene (carbene) :CH
in the singlet state is not a radical, but in the triplet state it is. However I have been told that free methylene cannot be called a "methylene radical" precisely because its ground state is the triplet. Which one is correct?
More generally, for the purpose of naming articles it seems we need a word meaning "has unsatisfied valence bonds", without regard for spin state. If "radical" is not OK, then what could we use?
The article mentions a "loose definition" of radical, namely "any chemically unstable molecule". But that definition is TOO lose, since it would include very unstable molecules like ethylene dione that are never called "radicals". Is there a "loose but not too loose" school that would allow using "radical" for any molecule with unsatisifed valence bonds? --Jorge Stolfi (talk) 17:29, 29 January 2013 (UTC)

Advice needed on proposed rewite of head section[edit]

Would some expert please check this draft, my attempt to expand the head section to make it a bit more accessible to non-specialist readers? Is the informal description "dangling bonds" appropriate, or misleading? Are the examples correct? Thanks, --Jorge Stolfi (talk) 12:17, 30 January 2013 (UTC)

  • Since there were no complaints, the head was rewritten. --Jorge Stolfi (talk) 08:18, 6 February 2013 (UTC)

Free radicals and health[edit]

Free radicals are the enemy in many books, magazines and web sites about health. There's scant mention here of this idea, from whether it's a justified concern (presumably) to (if so) which free radicals and the whys, wheres and hows of dealing with them. There's much buzz about antioxidants in the diet, from vitamins to plant extracts, which help deal with free radicals. Could this be added to the article, even if it's only to point to other articles which deal with the topic more fully? (talk) 11:07, 8 August 2013 (UTC)

  • the article already has a section on biology with links to relevant articles such as antioxidant and Free-radical theory. Health issues could be expanded in articles such as these. V8rik (talk) 19:37, 8 August 2013 (UTC)

Requested move 4 August 2015[edit]

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: not moved. ErikHaugen (talk | contribs) 23:39, 25 August 2015 (UTC)

Radical (chemistry)Free radical – the opening sentence says "In chemistry, a radical (more precisely, a free radical)...", and according to the last paragraph of the lead:

Until late in the 20th century the word "radical" was used in chemistry to indicate any connected group of atoms, such as a methyl group or a carboxyl, whether it was part of a larger molecule or a molecule on its own. The qualifier "free" was then needed to specify the unbound case. Following recent nomenclature revisions, a part of a larger molecule is now called a functional group or substituent, and "radical" now implies "free".

So clearly the scope of the article is about "free" radicals, not just any radical. Or perhaps free radical is the same thing as a radical in modern parlance. But either way, "free radical" is a legitimate and precise name for this article. And I think it's preferable to the current name because (a) I believe "free radical" to be the WP:COMMONNAME for this, and (b) it satisfies WP:NATURAL because the "(chemistry)" disambiguator is no longer needed. Thanks  — Amakuru (talk) 08:06, 4 August 2015 (UTC) Relisted. Jenks24 (talk) 06:48, 12 August 2015 (UTC)

  • Cautious support per WP:UCN and especially WP:NATURAL; I wait to make sure the nom's assertions are accurate. Red Slash 16:13, 4 August 2015 (UTC)
  • Support as common name, and cautious per Red Slash. Randy Kryn 1:31, 5 August 2015 (UTC)
  • Strongly Disagree As someone who worked in the field - the term free radical is almost never used. If you talk to most chemists they will automatically assume that radical refers to the species and not the substituent, most under the age of 50 won't be aware of the older meaning. Creating this distinction might actually make the non-expert reader think that the usage of radical without the 'free-' prefix is not referring to the species. For a less subjective and more fact based argument, I would also like to highlight the IUPAC guidance on this taken from Compendium of Chemical Terminology [R05066]: In the past, the term 'radical' was used to designate a substituent group bound to a molecular entity, as opposed to 'free radical', which nowadays is simply called radical. The bound entities may be called groups or substituents, but should no longer be called radicals. .--The chemistds (talk) 10:06, 6 August 2015 (UTC)
  • Comment As a chemist I'm not a fan, as the term 'free radical' has been deprecated from use for a while now, [1] but the WP:COMMONNAME for most readers is probably free radical. Might I suggest Radical (chemistry)Radical (free radical) as that would combine accuracy and searchability? --Project Osprey (talk) 10:58, 6 August 2015 (UTC)
Follow-up Comment I'd propose that maybe it would be better to have the redirect in the other direction Radical (free radical)Radical (chemistry). I see the logic of WP:COMMONNAME But I'm not sure that it is as clear cut as many of the example cases, because there is not such a big difference between the two article names, and I'd suggest because this is a slightly less popular term, there isn't so much of a popular awareness that would create the expectation of a common name (I realise this may be considered subjecive). --The chemistds (talk) 13:22, 6 August 2015 (UTC)
  • Support per Red Slash and Randy Kryn. --IJBall (contribstalk) 17:47, 11 August 2015 (UTC)
  • Oppose, I think. I get the naturalness arguments, but ultimately I think we have to look at what's best for encyclopedia. Is using a term that, as chemistds's source shows, is considered to be outdated by experts in the field a useful thing for us to show readers? Or would the reader be better off to have the deprecated term redirect here, and the article explain the old and new terminology? Personally I think the latter and it is one of those times when we should invoke this instruction from WP:UCN: "inaccurate names for the article subject, as determined in reliable sources, are often avoided". In addition, I will note that from the late '90s to 2008 the term "free radical" has seen a ~33% drop off in book sources (see ngram). Jenks24 (talk) 13:23, 20 August 2015 (UTC)
  • Oppose. Radical (chemistry) is perfectly fine as is, and properly encompasses the biradicals and diradical. The oxygen molecule is a radical but not a free radical, in terms of non-chemist usage, and on this point the proposal should be ruled out. --SmokeyJoe (talk) 09:02, 21 August 2015 (UTC)

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.
Hopefully someone will fix the problems Amakuru pointed out. ErikHaugen (talk | contribs) 23:39, 25 August 2015 (UTC)

Assessment comment[edit]

The comment(s) below were originally left at Talk:Radical (chemistry)/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

"Free radical" redirects here (intro bio topic) - tameeria 20:38, 5 May 2007 (UTC)

Last edited at 20:38, 5 May 2007 (UTC). Substituted at 03:48, 30 April 2016 (UTC)

The correct dot for radicals?[edit]

What is the correct dot for denoting radical? I see many uses of bullet but the online IUPAC Gold Book uses a super-scripted period, and apparently there are many more different dots. – says DD Tachibana 03:23, 19 May 2016 (UTC)