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Counterexamples please[edit]

This article, which isn't exactly a model of clarity but isn't bad, would benefit from some counter examples. That is, examples of chemical reactions which are not redox. In other words, a little more context please. Thank you. Macguba (talk) 09:54, 5 February 2009 (UTC)

Most of the reaction shown are not REDOX!—Preceding unsigned comment added by (talk) 11:12, 4 December 2010 (UTC)
Please provide specific examples which you feel are not redox. No way we can diagnose which "most" you mean. DMacks (talk) 18:35, 5 December 2010 (UTC)
How about NaOH + HCl = NaCl + H2O? That's clearly acid-base and not redox. Swfowkes (talk) 14:49, 16 June 2012 (UTC)

I'd like examples of redox reactions that do NOT involve electron transfer. Swfowkes (talk) 14:48, 16 June 2012 (UTC)

Needs etymological explanation[edit]

Would someone please add a section clarifying the usage "oxidation" (which obviously does not mean "adding oxygen") and "reduction" (what exactly is reduced?). Thanks. Tmangray 00:14, 1 February 2007 (UTC)

I agree entirely, in its current form this article is quite obfuscatory rather than explanatory, and well below Wikipedia's normal level of clarity. Please could someone rewrite it with the end user in mind. Thanks :)

Er, the following statements from the introductory section:

  • Oxidation describes the loss of electrons by a molecule, atom or ion
  • Reduction describes the gain of electrons by a molecule, atom or ion

seem quite clear and unobfuscated as a description of these terms. And a bit later in that section, we get a more proper definition:

Thus, oxidation is better defined as an increase in oxidation number, and reduction as a decrease in oxidation number.

Are those close to being clear, and a small wording-change could fix the whole problem? Or are those hopelessly confusing and we need to start over? DMacks 16:13, 20 February 2007 (UTC)

I'm still a litte confused, it seems like the simple definition and the detailed definition contradicts themselves? More incisively speaking, the simple definition states (in a nut shell) that oxidation is the loss of electrons and that redution is the gain of electrons...While the detailed description basically states the opposite of the two in that oxidation is to gain as reduction is to loss (which in turn contradicts the simple definition)...Am I making any sence? -Thanks Gunnar Berlin 21:09, 26 February 2007 (UTC)

Ahah! Remember that the electrons, the "things" that are being gained or lost, are negatively charged. So gaining negatively-charged things causes a lower charge. More electrons == lower oxidation state. DMacks 21:17, 26 February 2007 (UTC)

Thank you that definatly clears it up for me now--Gunnar Berlin 21:36, 26 February 2007 (UTC)

No wonder chemistry is such a difficult subject. Only a chemist would ever call a gain of something a "reduction". — Preceding unsigned comment added by Captain Quirk (talkcontribs) 09:52, 20 March 2012 (UTC)

Really? A gain in my capital corresponds to a reduction of my debt. Electron charge is negative as is debt, so in both cases we have to pay attention to the sign. Dirac66 (talk) 21:43, 21 March 2012 (UTC)


what are the reaction between a solution containing hydrated ethanedioic acid with sodium enthanedioate and hydroxyl ions?

Generally speaking, it is advised you use more well known and less cryptic names, namely oxalic acid and sodium oxalate. Also, unless you mean a free radical, they're called hydroxide ions. I'm guessing that oxalic acid is reacting with sodium hydroxide to make sodium oxalate, I can't see any other possible reaction. Kr5t 02:21, 29 March 2006 (UTC)

A mixture of oxalic acid and sodium oxalate is a buffer solution. If you add hydroxide ions you end up with a more basic buffer solution, by forcing the reaction toward the oxalate ions.

Id just like to know where the section on using redox reactions as a starting point to balance complicated chemical equations is. It seems that that was kind of an important thing to leave out. In case anyone doesn't know what I'm talking about, it uses the precept that charge, like energy, must be balanced in a chemical reaction. For example:

This isn't easy to balance on first look, but by finding the oxidation charges in the redox reaction, it can give you a start.

ΔC = 6 ΔO = 2 As you can see, the charge difference is not equal, but it could be made equal by multiplying the ΔO by 3. So try this in the eq (remember ΔO is the atomic, not the moleculer ratio)

Get rid of the fraction:

Spot check the last balance:

Sorry for the complicated example, but its a good one.

Just to clarify is iron a electron acceptor or donor?-- 14:50, 13 June 2007 (UTC)

Iron (0) is an electron donor, Iron (III) is an electron acceptor, Iron (II) can be either an electron donor or an electron acceptor but is generally the former.


Oxidation should be merged into this article!!! Reduction (chemistry) redirects to Oxidation. See Talk:Oxidation#Merge?. 12:17, 5 Nov 2004 (UTC)

Oxidation has been merged into this article.

Brianjd 06:43, 2004 Nov 7 (UTC)

Add titration to this article![edit]

I think this subject article would be better if the topic titration is added to it.

Why? What does titration have to do with redox?

Haha, not only are these totally different topics, acid/base reactions (transfer of H+ protons) are almost the exact OPPOSITE of redox reactions (transfer of e- electrons), so it's a humorous question, chemistry-wise. Jhum101 10:38, 7 March 2006 (UTC)

As a matter of fact, I always thought scientists in general ought merge the definitions. An acid base reaction can be transfer of proton, H+, Arrhenius definition and later refined Bronsted-Lowry, transfer of a pair of electrons, Lewis definition, or transfer of O2- ion, which I don't think has been named, but does occur:

CaO + CO2 -> CaCO3

wherein what really happens is O2- + CO2 -> CO32-

Also, Lewis definition defines it as bond making/breaking, also part of redox definition. Indeed, the Acid-Base Reaction Theories Page says that Usanovich tried defining it as transfer of negative positive charges or making/breaking bonds, exactly, pretty much, the definition of redox. It says scientists did not like Usanovich's definition because it overlapped with redox--step back and take a look, guys, they really not only overlap, they're the same.

EVEN ASSUMING EVERYTHING I JUST SAID WAS JUNK, there are as a matter of fact redox titrations. In fact, I did an experiment where I was trying to find the solubility product constant of calcium iodate, and the way I was doing this was by titrating the iodate ions in a saturated solution of calcium iodate with hypo, or sodium thiosulfate. The reaction between them

IO3- + 6S2O32- + 6H+ -> I- + 3S4O62- + 3H2O

is obviously redox.

Kr5t 02:13, 29 March 2006 (UTC)

There are many titrations that have nothing to do with redox; there are many redox reactions that have nothing to do with titration. Just because there are some examples of overlap doesn't mean the topics are the same (or even substantially related in principles) and even if there were substantial overlap of the subjects, it's okay to have related topics on different pages if there is a lot of material to cover on each. OTOH, if someone wanted to note on the redox and titration pages that some titrations use redox reactions and link between the pages, well that's certainly okay IMO. DMacks 04:59, 12 April 2006 (UTC)

My point is that there is titration in both and titration shouldn't be excluded from the redox page unless it is excluded from the acid-base reactions page as well. Point being that titration is equally important in both, so if there is any good reason to exclude or include titration in one page, it should be equally applicable to the other page. Acid-base: How strong an acid is acetic acid in vinegar? Go titrate it. Redox: How strong an oxidizing agent is hypochloric acid in bleach? Go titrate it. Kr5t 03:03, 19 April 2006 (UTC)

Neither the strength of an acid nor the strength of an oxidizing agent is determined through an acid/base or redox titration. These titrations, like all titrations, give the concentration. A potentiometric titration is usually used to determine the strength of an acid, while the strength of an oxidizing agent is determined through electrochemical means. The fact that a redox titration exists does not mean this page should be linked to titrations. Are you next going to link silver to the titration page because you can do an argentiometric titration? —Preceding unsigned comment added by (talk) 13:34, 19 February 2008 (UTC)

Right. I think we (at least Kr5t and I) are in violent at-least-semi-agreement here. As I said, I'm not opposed to including redox titrations here on the redox page. Or should we just mention that one can do a redox titration and then link to the Redox titration page (which could then be improved beyond its current stubbiness)? DMacks 04:19, 19 April 2006 (UTC)

It's not altogether too stubby right now. However, I think that's a lousy example. A simple one, like titration of laundry bleach, would be a whole lot better. Violent semi-agreement? Thats kindofa oxymoron...unless I don't understand what you're saying...which I don't...but anyhow, we do agree. Kr5t 21:03, 3 May 2006 (UTC)

Standardized Nomenclature[edit]

Chemical reactions should be denoted by "=", not by "→". The latter implies a net forward reaction, while the former implies a stoichiometric equation or an equilibrium (IUPAC,Italic text Quantities, Units and Symbols in Physical ChemistryItalic text, 2005).

This nomenclature emphasizes the thermodynamic reversibility of the reaction, the associated equilibrium constant, and (in the case of redox reactions) the associated redox potential.

Thus A + B = C + D implies K = exp(-ΔG/RT).

Btarski 18:26, 28 January 2006 (UTC)

Usually you are interested in a chemical reaction because you want to make something that you don't have out of something else that you do have. It's true that some equations are equilibrium in the plain sense (equilibrium constant is not on the order of 10^40), in which case you denote them by a double arrow, but many reactions, such as corrosion, fire, combustion, or most chemical laboratory executable reactions do get driven in one particular direction, because your equilibrium K is huge, in which case using the arrow should be fine, you're denoting your intent, what you're attempting to make, there should be nothing wrong with conveying that extra information in your equation. Anyone with a proper chemistry education will know that every reaction is always an equilibrium reaction. For instance, magnesium will react with silicon dioxide to form magnesium oxide and silicon, but in the Pidgeon Process it's the other way around. The arrow you use denotes your intent, which way you're driving the reaction, whether towards making magnesium metal from silicon and magnesium oxide, or making silicon out of magnesium and silicon dioxide. Sillybilly 03:26, 29 January 2006 (UTC)

Agreed. I just glanced over to my open O-chem textbook, and one-way arrows are used for almost every reaction. Equal signs are never used, and if the equilibrium is important, the double arrow symbol, "⇌", is used. Jhum101 10:45, 7 March 2006 (UTC)

If you want to standardize it, going for a nonstandard standard isn't the best way to go about it ;)(heh). Chemical reactions have never used the equal sign and probably never will. When a reaction has an extremely high K value, orequilibrium constant, a singlle arrow is used, otherwise a double arrow is used (not included in normal fonts so I won't try to show it). Note--don't confuse equilibrium constant K with rate constant k. It's case dependant, so if k is large but K isn't (not very likely), it means that although it reaches equilibrium really fast, theres still more reactants than products present in the equilibrium mixture. Kr5t 19:47, 2 April 2006 (UTC)

Oxidation State Notation[edit]

I agree with the points about chemical reactions, they should definitely use arrows. However, I also think that when giving examples of redox reactions, we should use the standardized notation of putting the charge after the number for ions only. For example, when talking about oxidation states, using -2 for O makes more sense than 2-, since 2- denotes that oxygen is an ion. However, sometimes (especially in double replacement reactions) an ionic compound can be broken up and and reformed into covalent compounds. Since charge different must always be equal, one must still look at the charges of the elements, so you should use -2 in all cases just in case there are no ions (e.g. 2H02 + O02 -> 2H+12O-2) -Mirag3 21:36, 6 October 2006 (UTC)

Half-Reaction Method[edit]

The half-reaction method for balancing redox reactions should be added here. Morphine 23:12, 22 February 2006 (UTC)

It's all levels of understanding. COnsidering the sparse use of the half-reaction method in even Chem 1A, I think this page should just link to a page on the Half-Reaction method. Wanna make one with me? Kr5t 19:51, 2 April 2006 (UTC)

An explanation of how to balance Half-reactions is desperately needed - "Half reaction equation balancing" even redirects here, yet there's nothing! I'll check if there's any such content in Wikiversity... nope. Nothing there either! 09:46, 19 February 2007 (UTC)

Electronegativity is for atoms[edit]

Electronegativity is only for individual atoms, not allotropes of elements. Kr5t 19:52, 2 April 2006 (UTC) (This signature is a few days after I actually made this post--I didn't know how to sign posts back when I wrote this).

Mnemonic Devices[edit]

They are ugly. Good information but ugly. I’ve been thinking of ways to make them more attractive. Moving them under a separate heading might work but then they would be too far away from the original material to be of any help. Maybe bulleted… Does anyone have any suggestions? JohnJohn 01:52, 1 April 2006 (UTC)

They are, admittedly, ugly, and I apologize. Originally there was only OIL RIG, then I added LEO says GER, and that totally disrupted the flow. I think bulleted would be nice, especially since we ought to add these others: A RED(uction) CAT(hode) and AN(ode) OX(idation), and ReduCtion has a C(athode) but no A(node), and OxidAtion has a A(node) but no C(athode), both of which are for remeber which half reaction occurs at which electrode.

No, I disagree with the statement that mnemonics are disruptive. A good one can help one on many an exam or lab. I particularly favor the "LEO the lion says GER." Many students may find it an easier way to remember such pivotal facts, and it is certainly very creative. Pat on the back to whoever came up with it. --Samuel.ordonia (talk) 03:47, 1 April 2008

I bulleted them. You are right, though, they are still rather disruptive. JohnJohn 00:15, 4 April 2006 (UTC)

Oh, so thats how you bullet things! Maybe we should add some section at the end devoted to the various mnemonic devices (I'm sure there are others). Kr5t 21:25, 5 April 2006 (UTC)

I made "them" (I deleted one) small. The rest should go under a new section near the bottom. JohnJohn 16:21, 6 April 2006 (UTC)

They're back! I'm making a link to the section, so that it doesn't get ugly up there again JohnJohn 23:44, 15 September 2006 (UTC)

Oops! I don't know how to link to a section. I just deleted OIL RIG insteadJohnJohn 00:04, 16 September 2006 (UTC)

In my opinion, this section does not belong in an encyclopedia, plus it was tagged with original research. However, I'm a bit afraid of deleting an entire section. --Mizst 15:05, 14 July 2007 (UTC)

At the time the {{OR}} tag was added, there were no citations at all for the mnemonics. Since then, several have been added. The section is no longer pure original research in the wikipedia sense. I could go along with removing the uncited ones items, but I oppose removing the cited ones since they are cited and are certainly useful to some readers. DMacks 23:11, 15 July 2007 (UTC)
I understand it could be useful to some readers, but in my opinion this information does not belong in an encyclopedia. Also, if you check the citations, they do not look like a "reliable source" per wikipedia guideline. I am removing this section now, but if anyone disagrees they can roll it back. --Mizst 15:13, 16 July 2007 (UTC)
Removed. Unencyclopedaic: Wikipedia is not a how to. They were either OR or poorly sourced, class and lecture notes are not suitable sources. Vsmith 23:34, 16 July 2007 (UTC)
If there is one particularly famous one-word mnemonic for something otherwise hard, but good, to remember, I don't think the insertion of "(a mnemonic: FACE)" would be intrusive, distracting, or "counter-encyclopedic" enough to arouse objection. Unlike Britannica, we aren't particularly pressed for space here, and learning is a worthy endeavor. Unfree (talk) 04:42, 12 December 2009 (UTC)

People come to Wikipedia to learn. Mnemonic devices are a useful tool that utilizes characteristics of the human brain in order to strengthen the synaptic association of a memory. Therefor they should be put in this Wikipedia article. It follows necessarily. Arguments that they "don't belong" because they are not truly "encyclopedic" in nature is a logical fallacy of semantics. However I recognize that Wikipedia, strives to a certain standard of being encyclopedic, and in this situation, mnemonic devices being information, have a place according to Wikipedia's own guidelines [[1]]. In addition, the mnemonic devices are simply presented and are not part of a "How-to" instruction manual [[2]]. The mnemonic devices are simply being presented for information. Similarly it would be counter productive if you removed "Balancing Redox Reactions" because it was too instructional. Ristorilsm (talk) 15:32, 17 December 2009 (UTC)

I agree with Ristorilsm, saying they're idiotic is idiotic it's self. Whenever I'm trying to work things out, the first thing I think of is 'oilrig'. If you're striving to be like Oxford and the others, why not just have a link to Oxford and delete the entire article? —Preceding unsigned comment added by Johnheritage (talkcontribs) 21:31, 20 September 2010 (UTC)

Side note- I am now after studying chemistry for 6 years and doing a masters... I regularly use OIL RIG to confirm to myself I have done things the right way round. Wikipedia is an eduction tool for most, not a purist's encyclopaedia. I suggest suggested ways of remembering information should be included. — Preceding unsigned comment added by (talk) 19:43, 1 December 2011 (UTC)

An encyclopedia is there to convey information, not to help you remember it. The article should be about the principles of Redox. "Balancing Redox Reactions" pertains to its principles, therefore it belongs in the article. Mnemonics don't. In any case, those pieces were a combination of unsourced and poorly sourced material, so they had to be removed regardless. --Mizst (talk) 23:07, 5 February 2011 (UTC)
@Vsmith and Mizst: I appreciate your work on this article over the years. But like seven others who have commented above, and the multiple IPs who've added memory aids over the years, I also see the inclusion of a few common mnemonic as quite helpful here. I recognize that might seem redundant, trivializing, or embarrassingly "cute" to an expert, of course, to someone for whom these terms are so fundamental that they could never be forgotten. But I submit that your strong dislike for including the usual mmemonics here doesn't serve the "target audience" for this article, most of whom are not experts, but more likely beginning students who just want to understand the concept well-enough to use it productively. And, of course, it's necessary to consistently and correctly remember the definition of a term before one can use it productively.
Maybe a personal example will help you see the value. I studied chemistry in college, through second-year organic. That was years ago, however: I've forgotten most of what I learned, but have recently had occasion to want to revisit and refresh that tuition, very much as a slow-paced leisure project. I've looked at this article previously, in pursuing that re-learning, but when reviewing our Salt bridge article just now, I had to come here again to remind myself which was reduction and which was oxidation. I say "again" because I've had to come here for that same reason more than a few times as I've been reading other chemistry articles. I finally saw the "LEO says GER" mnemonic elsewhere on the web, something I'd never been exposed to before, and I'm sure I'll never forget which is which again. It seems to me that if I couldn't easily remember which is which, that a student who's entirely new to chemistry is unlikely to do so either, without some help. The names "oxidation" and "reduction" are far from intuitive, after all.
Further, I find the opinions and policy arguments made by some of the seven editors who've commented above to be convincing. I likewise note that very common mnemonics are included in other of our articles. Cranial nerves, for example, includes a fairly long section on the mnemonics ubiquitously employed for that topic, and we even have a completely separate article that lists them. I really do understand your distaste for a mnemonic in this article; it doesn't seem very "scholarly". But will you please try to put your expert's familiarity to one side, to give students who are new to chemistry ( most of the readers who come here, I should think ) a better chance to remember and thus usefully understand the article's subject? I'd really appreciate it if you'd let the well-cited "Memory aids" section that I've just added stand, for the benefit of the most likely readers of this article, despite your dislike for the content. Thank you.  – OhioStandard (talk) 23:50, 8 July 2011 (UTC)
Scholarly distaste aside, the main reason the mnemonics were removed (years ago) was because they were unsourced or had very poor sources. When it is properly written, well-sourced, and formatted in such a way that does not encourage endless appending, there is certainly room for flexibility. I do admit to disliking it, but I do not plan on being obstinate either. Your created section is excellent. Thank you for your very valuable contribution. --Mizst (talk) 19:02, 29 August 2011 (UTC)


This article could use a description of what a poised reaction is, and why poise is a significant concept when working with redox. Vague references to optimal redox poise is all I have so far. -- Paleorthid 03:57, 19 April 2006 (UTC)

So far, so good. It seems to be all about finding the optimal ambient redox potential in the reaction center for fitting a certain model of a cyclic electron transfer metabolic pathway. I'm a bit hazy about the progressive pre-reduction business, but it also refers to the redox potential. The "poise" is probably a potential found by the titration experiments at which the reaction rates imply no tendency to go one way or the other. The dynamics of cytochrome reactions in heme ought to be a fascinating and profitable area of research, especially for marathon runners, but I never got past 450. :) Unfree (talk) 05:56, 12 December 2009 (UTC)

Oxidation and reduction properly refer to a change in oxidation number[edit]

Quote(line 10) :Oxidation and reduction properly refer to a change in oxidation number — the actual transfer of electrons may never occur. "the actual transfer of electrons may never occur" is this statement true for all types of chemical bond or only covalent bonds [This edit by Mehan20 dated 23 Nov 2006]

OK, I have a disagreement with both of these statements. First, oxidation number is an artificial construct assigned to an atom based on relative electronegativities of adjacent atoms. In other words, are the shared electrons on carbon or hydrogen? In reality, they are merely more on one than the other. So oxidation numbers could be more accurately represented by 1.2 or 2.5 than the integers traditionally used.
Second, please give me one example (or ten, if you will) of a redox reaction where electrons transfer is not (NOT) involved. Electrons are transfered in covalent bond formation, and in redox reactions involving covalent bonds (the oxidation of an alcohol to an aldehyde, for example).
Please pardon my ignorance of Wiki process. This is my first time trying to figure out the underlying process that has taken place or might have taken place regarding this "actual transfer of electrons may never occur" which makes no sense to me. Rather than just deleting the statement, I'm asking for an explanation from the 100+ contributors who seem to approve of this language. My edit would state, "All redox reactions involve the transfer of electrons." Period. If I might abstract is a different way, the electrons may transfer by 99+% (as in sodium to chloride) or by 52% (as in carbon to hydrogen), but when we assign an integer oxidation number, we are merely rounding out the electron fraction (or electron-transfer fraction).
Partial charges are often represented by delta plus or delta minus symbols, and by arrowheads on the bonds describing induction, and by arrows on double bonds representing back-donation between a sp2 carbon and a fluorine. Are these not "actual" electron transfer? ---swfowkes — Preceding unsigned comment added by Swfowkes (talkcontribs) 14:23, 16 June 2012 (UTC)
I agree that the concept of redox needs better definition in this article. The linked article on oxidation state does explain the traditional meaning of the term with integer or simple fractional values. But we could add a mention of this fact in this article as well, and also specify that the oxidation states often do not correspond to the partial charges from quantum chemical calculations.
The concept of electron transfer also needs a more precise definition which will require some thought. I disagree however with just saying that "All redox reactions involve the transfer of electrons," because some reactions not usually considered redox also involve movement (or "partial transfer") of electrons. For example nucleophilic substitutions.
I also agree that many of the statements in this article need specific examples and in some cases counter-examples for clarity as to exactly what is meant. There is work to do. Dirac66 (talk) 20:22, 16 June 2012 (UTC)

Oxidize links to this page.[edit]

A typical dictionary definition of oxidize would be:

1. To combine with oxygen; make into an oxide.
2. To increase the positive charge or valence of (an element) by removing electrons.
3. To coat with oxide.

By linking oxidize to Redox we are ignoring the broader definition.

Gregogil 19:48, 5 February 2007 (UTC)

Thank you for your suggestion! When you feel an article needs improvement, please feel free to make those changes. Wikipedia is a wiki, so anyone can edit almost any article by simply following the Edit this page link at the top. You don't even need to log in (although there are many reasons why you might want to). The Wikipedia community encourages you to be bold in updating pages. Don't worry too much about making honest mistakes — they're likely to be found and corrected quickly. If you're not sure how editing works, check out how to edit a page, or use the sandbox to try out your editing skills. New contributors are always welcome. DMacks 19:55, 5 February 2007 (UTC)

Fenton's Reagent[edit]

Adding the reactions of H2O2 and Fe together is misleading since it leads to fenton's reagent. Why not use an example that is real? wikipedia says on that

(1) Fe2+ + H2O2 → Fe3+ + OH· + OH−

(2) Fe3+ + H2O2 → Fe2+ + OOH· + H+

In the net reaction the presence of iron is truly catalytic and two molecules of hydrogen peroxide are converted into two hydroxyl radicals and water. The generated radicals then engage in secondary reactions. Iron(II) sulfate is a typical iron compound in Fenton's reagent.

Here is something else interesting according to wikipedia on

Oxidant Oxidation potential, V Fluorine 3.0 Hydroxyl radical 2.8 Ozone 2.1 Hydrogen peroxide 1.8 Potassium permanganate 1.7 Chlorine dioxide 1.5 Chlorine 1.4

I read somewhere that fenton's reagent occurs under acidic condition with about a pH of 3 to 6. Then a much more powerfull oxidizing solution occurs. Why not pick an example that is true in reality and not oversimplified freshman BS —The preceding unsigned comment was added by (talk) 20:43, 21 March 2007 (UTC).

Spelling oxidized vs oxidised[edit]

I just changed a page (Sarett_oxidation) where it was spelled oxidised to oxidized, and sombody changed it back... Both words get this page when searching. Is that the american vs english way to spell the world? ChristianB 11:07, 3 July 2007 (UTC)

Yup, the Rambunctious Colonies use the "z", the Tea-Drinkers the "s". See WP:ENGVAR for the main Wikipedia guideline about this issue. DMacks 00:58, 4 July 2007 (UTC)

OIL RIG[edit]

Isn't there the mnemonic OIL RIG to help with whether the reaction has a loss or gain in electrons? --JustWong (talk) 18:00, 30 June 2008 (UTC)

There are several (at least!) mnemonics to help remember what's happening in a redox reaction. Read the above "#Mnemonic Devices" section to see why they are not in the article. DMacks (talk) 18:09, 30 June 2008 (UTC)
OIL RIG: Oxidation Is Loss (of electrons); Reduction is Gain (of electrons). Ah, high school chem memories! Bsimmons666 (talk) Friend? 01:10, 12 November 2008 (UTC)

Another mnemonic device I find helpful is LEO the lion says GER. notice the capitalized words LEO and GER. Loss of Electrons is Oxidation and Gain of Electrons is Reduction. Hope this is helpful to somebody!! <Its in the Alberta Chem 20/30 textbook anyway lolz> —Preceding unsigned comment added by (talk) 21:32, 6 November 2010 (UTC)

Can somebody explain these "simple terms"?[edit]

I can't understand this. What does this mean? What does the slash (/) signify? Is it a logical "and", "or", or "equivalent to"? Is the loss of an electron the same as a loss of hydrogen? Is the loss of an electron always accompanied by a loss of hydrogen? Can oxidation be either the loss of an electron or a loss of hydrogen?

It can be explained in simple terms:

  • Oxidation describes the loss of electrons / hydrogen or gain of oxygen / increase in oxidation state by a molecule, atom or ion.
  • Reduction describes the gain of electrons / hydrogen or a loss of oxygen / decrease in oxidation state by a molecule, atom or ion.
Agree and took out the hydrogen and oxygen from the "simple terms" explanation. Vsmith (talk) 02:10, 29 August 2009 (UTC)

State versus number[edit]

If oxidation state isn't quite accurate, and oxidation number is, why even mention "state"? (If it's an important subject, it deserves an article.) Also (since I've already changed "describes" to "is"), why not put "increase in oxidation number" in parentheses immediately following "oxidation", and state simply that it "is a loss of electrons by ..."? Unfree (talk) 04:21, 12 December 2009 (UTC)

From reading the sections on oxidation number and oxidation state, it seems to me that oxidation state is more accurate. While often the same number, oxidation numbers seem to be used in coordination chemistry and are represented by roman numerals. Oxidation state seems to refer specifically to the degree of oxidation of an atom. Please correct me if I'm wrong. — Preceding unsigned comment added by (talk) 18:15, 9 June 2011 (UTC)

Exothermic Reactions[edit]

Can We add a line about Oxidation reaction is mostly an exothermic reactoin. i.e whenever an oxidation reaction takes place. heat(Energy) is released. This energy is actually used by many living organism for sustainence. Ap aravind (talk) 07:00, 15 January 2010 (UTC)

Heat might not escape if you oxidize gold for example, which is very difficult to oxidize. --Cheminterest (talk) 22:14, 7 April 2010 (UTC)

If "redox" is shorthand for "reduction-oxidation reaction" - why ...[edit]

If "redox" really is a shorthand for "reduction-oxidation reaction" as the introduction says - why does the article all way long have the sentences "redox reaction [...]"? --Christian75 (talk) 19:19, 31 August 2010 (UTC)

Sounds inconsistent yes. I fixed it (took out "reaction" in the parenthetical). I think the shorthand-for comment was for the bolded parts ("reduction-oxidation" only), not the whole phrase. Maybe it was originally "redox reactions, shorthand for reduction-oxidation reactions" or some other more obviously parallel wording? And maybe it should be that way? Is the thing really "redox", or is it more correctly a unified phrase "redox reaction" for the article topic? DMacks (talk) 21:55, 20 September 2010 (UTC)

DMacks is right. Redox is a contraction of reduction-oxidation because oxred is to difficult to enunciate. "Redox reaction" is shorthand for reduction-oxidation reaction (the parallel construction) and oxidation-reduction reactions (as it is verbally stated in 99+% of conversations / discussions. [Has anybody actually ever heard anybody else say reduction-oxidation reactions?] Swfowkes (talk) 14:40, 16 June 2012 (UTC)

Carbon listed as a metal[edit]

As far as I know, and according to the wiki entry for "Carbon", it is non-metallic. However, carbon is included in a list of metals in this Redox wiki article. Someone more knowledgeable than I should consider that and edit if necessary. (talk) 00:49, 30 January 2011 (UTC)

I noticed the same thing, and I went ahead and changed it. Hope we haven't missed something. (talk) 04:16, 14 April 2011 (UTC)

I agree. Carbon is not a metal. However, it is commonly a semiconductor in its sp2 and sp1 geometries, which might appear to me "metallic" in concept. But metallic conducting electrons and pi-bond conducting electrons are quite different and distinct. Has anybody ever argued a theoretical similarity between the two? Swfowkes (talk) 14:39, 16 June 2012 (UTC)

Help with Captain Kidd's cannon[edit]

Hello. I am the Wikipedian-in-Residence at the Children's Museum of Indianapolis, which is opening a new permanent exhibit this weekend that includes Captain Kidd's Cannon as one of its central artifacts. They are placing QR codes to Wikipedia articles in the exhibit and were interested in a few articles being updated with more specific information about electrolytic reduction in regards to iron and salt water. The museum has a lot of research & videos regarding the conservation of the cannon and we'd like to share these with Wikipedians to update appropriately (perhaps in the redox article, the William Kidd and Captain Kidd's Cannon articles.) Is there someone available with enough basic knowledge to be able to write intelligently about this? Thanks so much.LoriLee (talk) 15:24, 14 June 2011 (UTC)

I can certainly give it a try. I don't know anything about the cannon itself, but redox is pretty straightforward (despite how confusingly it's often taught!) given known chemicals as reactants and products. Probably goes best in the article about the cannon itself, since it sounds like just one specific application of this very general chemistry idea (nothing special or new in regards to redox or the person). DMacks (talk) 11:40, 29 June 2011 (UTC)

Oxidisation of Polyethylene[edit]

Does anyone know whether this happens or not? (talk) 22:34, 9 November 2011 (UTC)

Answer Thankyou User:Vespine (talk) 05:39, 10 November 2011 (UTC)

Suggested move to Oxidation-reduction reaction[edit]

Should the title of this article be changed to Oxidation-reduction reaction, which is the correct term? Redox is just an abbreviation which can be explained in the first paragraph, and maintained as a redirect of course. Dirac66 (talk) 02:33, 14 December 2011 (UTC)

Actually this article has been discuss many times, either it should merge or change to other title. But from the review of this article by many Wikipedians before, it is confirm that Redox is better for this article's title. You can check from Talk:Oxidation . Anyway after Oxidation and Reduction merge into this article, the explaination for these reaction just shown not enough. I suggest adding some materials into these two reactions. Regards. Palaxzorodice (talk) 02:56, 14 December 2011 (UTC)

Thanks. That previous discussion seems to be about not having two separate articles, one for Oxidation and one for Reduction. I agree that the articles should be combined since you can't have Oxidation without Reduction and vice versa. But I think the title of the combined article should be the complete term Oxidation-Reduction reaction, rather than an abbreviation. Dirac66 (talk) 03:08, 14 December 2011 (UTC)

"Stub" one and point it at the other. I vote for "redox" as the primary page and "oxidation-reduction" as the stub page because redox is so commonly used in speaking and writing, and because is in the more inscrutable term for users wanting clarification of meaning. Swfowkes (talk) 14:44, 16 June 2012 (UTC)

I hope you mean redirect rather than stub. We do have a redirect now, so if a reader searches for oxidation-reduction s/he is pointed to this article. A stub in wikispeak would be another short article called oxidation-reduction in addition to this article on redox, and I think there is no need for that. Dirac66 (talk) 20:40, 16 June 2012 (UTC)

New Concept of Redox Reaction in terms of Changes in Electron Density[edit]

Many a times , it may be difficult to interpret the reaction as redox reaction according to all the three concept namely: classical, electronic and oxidation number approach.
For example:
CH3NCO(g) + H2O(l) → CH3NH2(g) + CO2(s)
In view of the above quoted examples and many other similar type of reactions a fresh relook into discussion for redox process is necessary. Recently in 1997 a more broad concept of redox processes has been proposed in the terms of change in the electron density.
According to that concept
(i) Oxidation is a process in which there is decrease of electron density.
(ii) Reduction is a process which involves increase in electron density around the atom involved in the reaction.
In the above reaction N atom of isocyanate (-NCO) group gets converted into -NH2 group by the replacement of the CO by less electronegetive H atom, causing increases in the electron density around the N atom. While C atom of -NCO group changes to CO2 causing decrease of electron density around the C atom due to the replacement of N by another O atom which is more electronegetive. Thus N atom of -NCO gets reduced and the C atom gets oxidised.
The electron density concept provide more logical explanation about redox trend. For example oxidative trends of halogens towards the gas phase reaction of methane and halogens.
As this concept is a recent idea it has yet to win the wider favour of chemists. — Preceding unsigned comment added by Mr Burman (talkcontribs) 07:01, 13 August 2013 (UTC)

Can you provide a precise reference in the chemistry literature for this theory? "Recently in 1997" does not give enough information to find the article(s). Dirac66 (talk) 10:28, 13 August 2013 (UTC)
In terms of the style of content, Wikipedia is not a textbook per WP:NOTTEXTBOOK, so one needs to be careful. In terms of the science, oxidation contracts the radius of the oxidized atome, which would imply that electron density does not decreases upon oxidation.

oxygen reduction reaction needs independent page[edit]

In the quest for sustainable energy source, fuel cell is an alternative which replace the carbonaceous fossil fuel. Among many kinds of fuel cell, the oxidation of hydrogen is a representative reaction where oxygen is reduced. In anode hydrogen is oxidized and changed into proton and electron then the electron flow to cathode through circuit. The reduction of oxygen into water together with proton which comes through electrolyte, and electron is crucial step for hydrogen burning cell where oxygen reduction reaction is so important. Therefore many catalysts for oxygen reduction reaction are developing.

This might be applied to reverse reaction of water splitting solar fuel cell where water is decomposed into hydrogen and oxygen. This is first step for artificial photosynthesis where the reduction of CO2 with hydrogen follows. For this refer to artificial leaf. — Preceding unsigned comment added by (talk) 02:13, 22 August 2013 (UTC)

We have another article on the fuel cell. Dirac66 (talk) 10:58, 22 August 2013 (UTC)

Is HF an ionic compound?[edit]

Here in this article HF is said to have ionic bond. But we were taught that HF is a co-valent compund with molecular structure and having hydrogen bond too. But here the equations and diagrams seems to say that it is an ionic bond. Which is true? Or are the words "ionic compound" and "co-valent compound" are loosely defined words? Can we define it properly?--G.Kiruthikan (talk) 06:35, 26 January 2014 (UTC)

No, HF is not an ionic compound. It is molecular in the gas phase, and is only a weak acid in water. The molecule HF does have a polar covalent bond, and yes, there are also hydrogen bonds between the molecules. This article (in the section Examples of redox reactions) analyzes the reaction of H2 and F2 as a series of steps. It is true that the ions H+ and F- are formed in one step, but the final step is that the ions combine to form HF which has a covalent bond. In reality the steps may not even occur separately - this is just one way of understanding the overall reaction. They would be separate however if the reaction is arranged to occur in an electrochemical cell, with H+ formed at the anode and F- at the cathode, and then meeting to form the final covalent molecule. Dirac66 (talk) 13:08, 26 January 2014 (UTC)
Thank you--G.Kiruthikan (talk) 03:39, 27 January 2014 (UTC)


Could someone discuss photo-oxidation such as in the aging of asphalt roofing products. Thank you. Jim Derby (talk) 00:11, 11 March 2014 (UTC)

We have articles on Photo-oxidation of polymers and Photooxygenation. Dirac66 (talk) 01:49, 11 March 2014 (UTC)

Oxidation and acidity[edit]

Hi everybody! I am asking myself if a statement like "acidity causes oxidation" can be correct in a general sense. Iron oxidizes under acidic conditions and also the oxidation states in the reaction given here under "Acidic media" increase strongly (while consuming acid). Can you therefore say that chemicals tend to oxidize in acidic media?--Polis Tyrol (talk) 09:24, 14 November 2014 (UTC)

Some reactions may be acid-catalysed, but one cannot make a general statement that "acidity causes oxidation". The "Acidic media" section describes how redox equations are balanced in acidic conditions. Please also note that talk pages should be used to discuss improvements to the relevant article; questions unrelated to Wikipedia should be directed to the reference desk. Adabow (talk) 10:07, 14 November 2014 (UTC)
Thanks for your answer and the comment. However, if a statement like that would be generally correct, this would be of great interest also for the Wikipedia article.--Polis Tyrol (talk) 15:05, 19 November 2014 (UTC)

Chemistry Series?[edit]

I know on some articles they have a box on the right which shows where the current article fits into the greater scope of science. Such as the page on Machine learning or Plants. Redox has a place in the scope of chemical reactions, and being able to quickly navigate through related concepts on the right without scrolling to "See Also" would be tremendously helpful. Jobonki (talk) — Preceding undated comment added 16:45, 2 January 2015 (UTC)

Electronegativity and electron sharing clarification please[edit]

Why wouldn't the oxidation state depend on the electronegativity of the elements involved? In the case H2 + F2 -> 2HF, it says that H is oxidized by 1. But doesn't this depend on how "much" the electrons are shared between H and F? If H and F shared them equally (i.e. if H and F had the same electronegativity), wouldn't there be no oxidation of H at all? After all, before the reaction, H is sharing electrons equally with H in the H2, so if it were still sharing them equally with F in the HF, why would there be any change in oxidation? But since they are not shared equally, and F has higher electronegativity than H, it makes sense to say that F "holds more of the electron" than H, and hence there is oxidation of H. But unless the bond is ionic, F is not holding 100% of the electron, so the oxidation change to H should be less than 1. If this is wrong, I'd like to see the article explain why. — Preceding unsigned comment added by Tedtoal (talkcontribs) 19:49, 29 July 2015 (UTC)

First note that new topics on the talk page should be placed at the end so I have moved your question. The answer is that the oxidation state is defined as the fictitious charge that an atom would have if all bonds to atoms of different elements were 100% ionic, with no covalent electron sharing. So the oxidation states in HF are +1 for H and -1 for F, even though we know that these are not the real charges and the molecule is not really ionic. These fictitious charges are explained more fully in the oxidation state article and are useful for balancing redox equations. I will add the brief definition above to this article. Dirac66 (talk) 23:48, 29 July 2015 (UTC)


The intro currently says, "A reduction reaction always occurs with an oxidation reaction." But that could mean any of the following things. Which is right? -- (talk) 19:58, 9 June 2016 (UTC)

  • A reduction reaction requires oxidation in order to occur
  • An oxidation reaction requires reduction in order to occur
  • All of the above. I.e., the two reactions always happen together.

— Preceding unsigned comment added by (talk) 19:58, 9 June 2016‎ (UTC)

The third is correct. There is a whole paragraph amplifying/explaining that aspect a few lines down in in the intro section, with things like "redox reactions are a matched set, that is, there cannot be an oxidation reaction without a reduction reaction happening simultaneously." The sentence you noticed is just one of the topic sentences for the whole intro section. I agree it was possibly unclearly written (though those are the same/similar terms I often see in textbooks) and definitely a surprising or non-obvious idea that can be pretty important. I rewrote the sentence to more clearly state that they always occur together. DMacks (talk) 20:09, 9 June 2016 (UTC)

Add a section on balancing a redox reaction?[edit]

I propose that we add a section on balancing redox reactions. Specifically, the steps needed (e.g. break into half reactions, balance equations (including hydrogen and oxygen), add electrons to both reactions, multiply by the number of electrons in each reaction, combine the reactions). This would be pretty helpful to new readers.

Here's the detailed list from a reputable source: [1].

If anyone is interested in this, please comment below.

Neilc314 (talk) 22:37, 25 August 2017 (UTC)

As a starting point, we now have section 9.Balancing redox reactions. However it is incomplete because it only considers reactions in aqueous solution. Dirac66 (talk) 02:27, 26 August 2017 (UTC)
I agree with user Neilc314!.--AlfaRocket (talk) 19:47, 27 August 2017 (UTC)