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Archive 1 |
Just seen new post of oxidation state. Going to attempt to combine them... user:sodium
Attempt completed. The two articles are displayed below, in case I have made any errors or left out text. I did not include some of the bottom of oxidation state as it was not directly relevant, having been taken out of the electrochemistry article (actually some of the text was written by me!) user:sodium
(former oxidation state):
Oxidation state (also referred to as oxidation number) is a convenient conceptual aproximation when working with complex electrochemical reactions. It eases tracking the electrons and verifying that they have been conserved when expressing complex half reaction equations involved in oxidation-reduction reactions.
The oxidation state of an ion is the number of electrons it appears to have compared to its neutral state (which is defined as having an oxidation state of 0). If an atom or ion donates an electron in a reaction its oxidation state is increased, if an element accepts an electron its oxidation state is decreased.
The following rules define oxidation number:
1.) The atom with the greater Electronegativity of disimiliar atoms sharing an electron is counted as receiving the electron.
2.) Identical atoms sharing an electron are each credited with one/half of the electron.
For example when sodium (electronegativity of 0.9) reacts with chlorine (electronegativity of 3.0), sodium donates one electron and gains an oxidation state
of +1. Chlorine accepts the electron and gains an oxidation state of -1. The sign of the oxidation state
(positive/negative) actually corresponds to the value of each ion's electronic charge. The attraction of the
differently charged sodium and chlorine ions is the reason they form an ionic bond with each other.
The loss of electrons of a substance is called oxidation, and the gain of electrons is reduction. This can be easily remembered through the use of the mnemonic, OIL RIG: Oxidation Is Loss Reduction Is Gain. The substance which loses electrons is also known as the reducing agent (reductant,) and the substance which accepts the electrons is called the oxidising agent (oxidant.)
A reaction in which both oxidation and reduction is occuring is called a redox reaction. These are very common; as one substance loses electrons the other substance accepts them. Redox reactions are the basis for ionic bonding.
Despite the name, an oxidation reaction does not necessarily need to involve oxygen. In fact, even fire can be fed by an oxidant other than oxygen: Fluorine fires are often unquenchable, as fluorine is an even stronger oxidant (it has a higher electronegativity) than oxygen.
(former oxidation number):
The oxidation state or oxidation number is defined as the sum of the negative and positive charges in an atom i.e., the number of electrons it has accepted or donated.
Atoms are considered to have oxidation numbers of zero, meaning that they are electrically neutral. The positive protons in the nucleus balance the negative electron cloud surrounding it, there being equal numbers of both. If an atom donates an electron it has more protons than neutrons and becomes positive. This ion is said to have an oxidation number of +1. Conversely if an atom accepts an electron it becomes negatively charged, gaining an oxidation number of -1.
Oxidation numbers are denoted in chemical names by bracketed roman numerals placed immediately after the relevant element. For example, an iron ion, with an oxidation of +3 is expressed as iron (III). Manganese with an oxidation state of +7 present in manganese oxide is given the name manganese (VII) oxide. The motive for placing oxidation numbers in names is only to distinguish between different compounds of the same elements. The actual charge (positive/negative) of the ion is not expressed because it is not necessary for this purpose.
In chemical formulas, the oxidation number of ions is placed in superscript after the element's symbol. For example, oxygen (II) is written as O2-. Oxidation numbers of neutral numbers are not expressed. The following formula describes the element I2 accepting two electrons to gain an oxidation number of -2.
I2 + 2e- -> 2I-
Sometimes it is not immediately evident what the oxidation number of ions in a molecule are from its molecular formula. For example, given Cr(OH)3, no oxidation numbers are present yet it is clear that ionic bonding is occuring.
There are a number of rules that can be used in determining an ions atomic number:
The problem with rules this hard coded is that there will be exceptions. For example, what's the oxidation number of the oxygen in superoxide? David M
BTW, there's a page for valency too. -- Tarquin
Looking at this page as a whole, I think it needs a comprehensive rewrite to clarify things. The way it is currently, rules for ionic compounds are mixed in with rules for covalent compounds in a confusing way. We need some more graphics and some covalent examples, including one or two organics. I will attempt to do this when I get a chance- unless anyone else is offering...
Walkerma 16:54, 11 Feb 2005 (UTC)
hi friends i want to know which of the following has more than one oxidation numbe 1)H2S2O4 2)H2S2O7 3)H2S2O7
I am not sure if you realize that choices 2) and 3) are the same. -- 132.1.207.22 ( talk) 23:24, 25 March 2010 (UTC)
Should we add a separate section that list the rules for determining oxidation number in organic chemistry? For instance, to determine whether an oxidation or reduction has occurred: (the following is an excerpt from page 459 of Organic Chemistry 3rd Ed, Mark Loudon)
In organic chemistry, whether a transformation is an oxidation or a reduction is determined by the oxidation numbers of the reactants and products. The calculation and use of oxidation numbers is a "bookkeeping" process that involves three steps. ... 1. Assign an oxidation level to each carbon that undergoes a change between reactant and product by the following method: a. For every bond from the carbon to a less electronegative element (including hydrogen), and for every negative charge on the carbon, assign a —1. b. For every bond from the carbon to another carbon atom, and for every unpaired electron on the carbon, assign a zero. c. For every bond from the carbon to a more electronegative element, and for every positive charge on the carbon, assign a +1. d. Add the numbers assigned under (a), (b), and (c) to obtain the oxidation level of the carbon under consideration. 2. Determine the oxidation number Nox of both the reactant and product by adding, within each compound, the oxidation levels of all the carbons computed in Step 1. Remember: consider only the carbons that undergo a change in the reaction. 3. Compute the difference Nox(product) — Nox(reactant) to determine whether the transformation is an oxidation, reduction, or neither, a. If the difference is a positive number, the transformation is an oxidation. b. If the difference is a negative number, the transformation is a reduction. c. If the difference is zero, the transformation is neither an oxidation nor a reduction.
does any one think this is college stuff?
can someone explain the term "collateral measurements?"
I see mention of the lower oxidation state of an element, namely Iron, being referred to as Ferric(2+), while the higher oxidation state referred to as Ferrous (3+). Is it not the other way around?
203.28.115.121 03:55, 20 January 2006 (UTC)
The Oxidation state entries for chemical elements (using Template:Elementbox_oxistates) seem to follow a specific format. For instance for Lead: 4, 2. Both the fact that 4 is listed first and that 2 is in bold seem to be meaningful (something about "standard" states?), but I did not see it explained anywhere. I think this article might be the good place for that.
About the phrase "For an exhaustive list of the possible oxidation states of each element, see the Standard Periodic Table" does not make sense, because for instance C is listed with 4 and 2, while the article just mentioned all states from -4 to 4 are valid. This should be explained. I saw originally this was an outside link, (not responding now, but with data from http://www.chemicool.com/), which indeed mentions for C: minimum oxidation number: -4, maximum oxidation number: 4 (with a confusion betwwen ox number and ox states?).
I'm sorry I cannot help more, I'm not a chemist and this is just confusing, I hope somebody with the knowledge will help clarify.
Daniel Bonniot de Ruisselet ( talk) 08:58, 26 November 2007 (UTC)
You can determine the highest common oxidation state of C or any other element on the Periodic Table by looking at the Group number. Basically the highest common oxidation state is the number of valence electrons an element has. To get the maximum, you determine the amount it needs to give up(cations), or receive(anions), to become isoelectronic with the big 8's.
Ex: highest common oxidation state for Carbon: +4; Lowest: -4. highest common oxidation state for Sulfur: +6; Lowest: -3 —Preceding unsigned comment added by 71.107.21.156 ( talk) 05:15, 10 December 2007 (UTC)
can you please explain why O2F2 is not considered a peroxide? RolfSander ( talk) 13:54, 3 September 2009 (UTC)
The above discussion leads me to ask: why does the article say -2 in "most oxides"? If we exclude OF2 as an oxide, why not "all oxides" or just "oxides"? Are there exceptions which are clearly oxides? Dirac66 ( talk) 17:25, 3 September 2009 (UTC)
In the image showing the acetaldehyde reaction (redox reacctions), the oxidation states of the two C atoms are shown with roman numerals. However, the clarification of the differences between "oxidation states" and "oxidation numbers" suggests that roman numerals are used for showing oxidation numbers, while arabic numerals are used for oxidation states. if anyone has the wherewithal to edit the svg file these perhaps ought to be swapped out with -3, +1, -3, and +3. — Preceding unsigned comment added by 68.238.86.7 ( talk) 05:03, 6 July 2011 (UTC)
Does anyone know whether this happens or not? 82.36.181.113 ( talk) 22:34, 9 November 2011 (UTC)
May I suggest that the articles on Oxidation state and Oxidation number are so similar that they should be merged. One section of the merged article would be sufficient to explain the small difference between the terms in coordination chemistry.
My attention was drawn to the similarity on examining yesterday's edit of this article by Bgwhite, summarized as "Remove interwiki links as they point someplace else in Wikidata". In fact this editor removed 36 of the 41 interlanguage links, apparently because they pointed to articles in other languages which pointed back to Oxidation number and not here to Oxidation state. (At least this seems to be true for French, Spanish, German, Dutch and Russian, though not for Italian which was retained here.) In any case the Wikipedias in these languages all seem to have only one article, whether the title translates as Oxidation state or Oxidation number. So why do we need two articles in English for what is basically one concept? Dirac66 ( talk) 01:04, 8 May 2013 (UTC)
This is a minor issue, but I stumbled over it. At Oxidation state/Archive 1 § General rules for determining oxidation states without use of Lewis structures:
It seems the parenthetical is actually a required part of the statement (i.e. not parenthetical) in order for it to be correct, right? That is, in all compounds of two halogens other than Fl, the more electronegative element has an OS of −1. —[ AlanM1( talk)]— 22:50, 1 September 2013 (UTC)
I feel a sense of deja vu, this is how it was before I rewrote the confusing and contradictory oxidation number article! Unnfortunately I was out of the country when this merge was agreed and made, and it had dropped off my watchlist.
This merged article has problems. Oxidation number is not given any prominence and yet that is what a lot of kids are taught not oxidation state. Some references are wrong, and it doesn't flow. Oxidation state as understood by older chemists and oxidation number as taught are different in detail and that has been obscured. I shall go back to the pre-merge version of oxidation number and try to put this merged version right. Axiosaurus ( talk) 16:10, 10 September 2013 (UTC)
Axiosaurus ( talk) 05:10, 11 September 2013 (UTC)
http://books.google.ca/books?id=FRfcVwFr17IC&pg=PA543&lpg=PA543&dq=Spencer+Chemistry:+Structure+and+Dynamics+oxidation+state+Lewis+structure&source=bl&ots=PnvAGDKbVV&sig=CLcSZCFloSDI13wkvQggj6l5e64&hl=fr&sa=X&ei=R540UvrMG8XG4AO-2oGoAQ&ved=0CEcQ6AEwAw#v=onepage&q=Spencer%20Chemistry%3A%20Structure%20and%20Dynamics%20oxidation%20state%20Lewis%20structure&f=false Dirac66 ( talk) 17:53, 14 September 2013 (UTC)
The previous section notes a contradiction in the article concerning B-H bonds. Yes, of course the chemical consensus is that H is -1 when bonded to B. The only way I can understand the IUPAC list of exceptions is that it is not meant to be exhaustive. Exceptions ... are does not mean The only exceptions ... are. So yes, H is -1 when bonded to active metals (whatever that means exactly), but also when bonded to other metals as well as boron. Perhaps this point should be made in the article. Dirac66 ( talk) 00:55, 15 September 2013 (UTC)
I removed the word "formal" whenever it appeared in "formal oxidation number". I hope this is okay. 178.38.121.208 ( talk) 06:38, 23 October 2014 (UTC)
Oxidation itself was first studied by Antoine Lavoisier, who believed that oxidation was always the result of reactions with oxygen,[16] thus the name. Although Lavoisier's idea has been shown to be incorrect, the name he proposed is still used, albeit more generally.
This seems to be using the term oxidation both circularly and anachronistically. If Lavoisier believed that oxidation always involved a reaction with oxygen, and this was a contentful statement rather than a tautology, then what did he mean by oxidation such that his belief could later be falsified? Whatever he meant by it should be described in this sentence by a word other than "oxidation", and the historical development will make more sense.
The following is closer to correct (and I have implemented it in the article). It's still anachronistic though, since Lavoisier could not have truly grasped what we now mean by oxidation. So what did he mean?
Oxidation itself was first studied by Antoine Lavoisier, who believed that what we now call oxidation was always the result of reactions with oxygen,[16] thus the name. Although Lavoisier's idea has been shown to be incorrect, the name he proposed is still used, albeit more generally.
178.38.121.208 ( talk) 06:52, 23 October 2014 (UTC)
A new second paragraph added today reads The term "oxidation" is derived from the element oxygen, which was the first atom known to pull electrons in a molecule toward itself, away from other atoms. Since Lavoisier is mentioned below, a historically naive reader might conclude that Lavoisier described oxidation in terms of electrons, which were in fact proposed over 100 years after his death.
A more historically accurate statement would be The term "oxidation" was first used by Lavoisier to mean reaction of an "oxidized" substance with oxygen. Much later, it was realized that the oxidized substance loses electrons, and the use of the term "oxidation" was extended to include other reactions in which electrons are lost. Dirac66 ( talk) 16:46, 2 November 2014 (UTC)
jingle baal jingle baal jingleall the way santa baba in the town osmium like hat ja way — Preceding unsigned comment added by 121.245.123.123 ( talk) 08:37, 26 December 2015 (UTC)
It is listed as Carbon has on oxidation state of +4 in Carbon tetrachloride. However ab initio calculations suggest, in CCl4, the negative charges residing on carbon (-0.28) and a very small positive charge on chlorine atoms (+0.07). Also, the bond dipole moment of H-C (1.13) is greater than that of H-Cl (1.03). Its is time to revise electronegativity scales.-- Anoop Manakkalath ( talk) 05:01, 10 January 2016 (UTC)
Czech wikipedia and literature mentions compound IrF9 (Iridium nonafluoride perhaps) as compound with iridium at oxidation state 9. Is it true? I cannot find anything about it in english literature. Thank you. -- Jade D Face ( talk) 13:06, 25 February 2016 (UTC)
A link to a IUPAC technical report entitled "Toward a comprehensive definition of oxidation state" has been added near the top and again near the end where the IUPAC project and the reasons for its initiation were mentioned. Mcardlep ( talk) 16:11, 20 June 2014 (UTC)
I intend to edit this page to reflect the publication of "Comprehensive definition of oxidation state (IUPAC Recommendations 2016)" http://dx.doi.org/10.1515/pac-2015-1204 This article is available free of charge. This definition is designed to address the problems created by the current limited and somewhat contradictory IUPAC definitions which have relied on algorithms for oxidation state and oxidation number. -- Mcardlep ( talk) 14:10, 27 October 2016 (UTC)
I have edited the history section of the page Mcardlep ( talk) 16:31, 6 October 2017 (UTC)
This major edit is timely since a much-needed clarification of Oxidation State (OS) has been provided by the definition of the term in IUPAC Recommendation 2016 (published after a five month scrutiny at the IUPAC web site and a peer review by 15 referees) and now also extracted into the IUPAC Gold Book. [1] [2] The Recommendation puts the term on a firm footing that provides two complementary algorithms to obtain OS in both molecular and extended-solid compounds. The definition, algorithms, and an example of a postulatory approach for early teaching levels, all form together the basis for the two revised Gold Book entries Oxidation State and Oxidation Number: [3] and [4] The previous situation was that IUPAC unintentionally contributed to some difficulties by providing quite different algorithms to define “Oxidation Number” and “Oxidation State” in its Gold Book, despite these terms being used almost synonymously. The latter fact is now clearly stated in the new Gold Book entry for Oxidation Number. The major revision of this Wikipedia page is urgent now because the previous Gold Book entries, on which this Wikipedia text was based prior this major edit, have been completely revised on June 28, 2017. This revision will reinforce Wikipedia’s standing as an authoritative source and provide useful and up-to-date information on important concepts in chemistry. Mcardlep ( talk) 14:09, 5 July 2017 (UTC)
I started the major edit. It is not yet finished as there are still diagrams to be added and some references need to be fixed. I have all the text and pictures ready but just not enough time to get them all up today. I will finish this asap. Mcardlep ( talk) 19:01, 9 October 2017 (UTC)
References
I added the "confusing" tag to this for one reason: when looking up "oxidation number", I actually had to go to the Simple English wiki to find a definition I could parse in less than 10 minutes.
Believe me, I understand how hard it can be to write for a non-expert audience. But remember, the kid taking a test or the Early Childhood Education major trying to pass a "general curriculum" teaching test needs to understand this article, too. And when that person Googles "oxidation state", this will probably be the first article they read.
The long-winded technical knowledge further down the article is fine, but I think the article would benefit enormously from an "explain like I'm 5" definition up top. Matereloah ( talk) 17:55, 5 November 2017 (UTC)
Thank you very much, Matereloah, for the reminder that there is such a good explanation in the Simple Wikipedia, https://simple.wikipedia.org/wiki/Oxidation_state. The best solution might be to place this link inside a short statement at an even more prominent early place in the main entry. A "more prominent" because, now, right below the heading "Determination of oxidation state", there is a statement that "introductory levels of chemistry teaching use postulated oxidation states", which is linked to a Section "Determination of oxidation state in teaching, prior to bonding considerations" with a more detailed descriptions. So it is there. The descriptions reveal that the task you wish to accomplish might not be easy because the "pre-bonding" postulatory definitions of oxidation state differ from textbook to textbook. Hence the Simple Wikipedia entry seems best. Karpmoi ( talk) 11:50, 8 November 2017 (UTC)
I propose to merge article List of oxidation states of the elements into this page Oxidation state. The list is a complete detail of this articler's topic, and so naturally fits in here. (Probably, in the early days the page would be too big but today that is not an issue).
Practically, we can add a section "List of ..." somewhere below. The actual table that has the OSs will be kept as a template ({{ List of oxidation states of the elements}}). - DePiep ( talk) 09:50, 2 March 2019 (UTC)
Ln and An are in fact in groups 6 and 7 respectively. Why does it say n/a? Porygon-Z ( talk) 04:38, 29 June 2019 (UTC)
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Reviewer: Keresluna ( talk · contribs) 19:16, 30 March 2021 (UTC)
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1. Well-written: | ||
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1a. the prose is clear, concise, and understandable to an appropriately broad audience; spelling and grammar are correct. | Very clear. |
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1b. it complies with the Manual of Style guidelines for lead sections, layout, words to watch, fiction, and list incorporation. | One or two have redundancy but good enough. |
2. Verifiable with no original research: | ||
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2a. it contains a list of all references (sources of information), presented in accordance with the layout style guideline. | |
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2b. reliable sources are cited inline. All content that could reasonably be challenged, except for plot summaries and that which summarizes cited content elsewhere in the article, must be cited no later than the end of the paragraph (or line if the content is not in prose). | |
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2c. it contains no original research. | Some are not sourced. |
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2d. it contains no copyright violations or plagiarism. | No apparent plagiarism or copyright violations. |
3. Broad in its coverage: | ||
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3a. it addresses the main aspects of the topic. | |
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3b. it stays focused on the topic without going into unnecessary detail (see summary style). | |
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4. Neutral: it represents viewpoints fairly and without editorial bias, giving due weight to each. | No issues noted. |
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5. Stable: it does not change significantly from day to day because of an ongoing edit war or content dispute. | Stable. |
6. Illustrated, if possible, by media such as images, video, or audio: | ||
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6a. media are tagged with their copyright statuses, and valid non-free use rationales are provided for non-free content. | Wish it had more media. For example, show the different compounds of each oxidation state of an element. |
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6b. media are relevant to the topic, and have suitable captions. | No issues. |
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7. Overall assessment. | Fail. |
I dispute the judgement of criteria 6. I count 20 images, mostly related to the "oxidation state algorithm" - this may fulfil 6a (although I agree that more images may be needed). 19 use the CC-BY-SA 4.0 License, while 1 is in the Public Domain, and none need captions as they are explained inline - this fulfils 6b. I hope this helps! Bibeyjj ( talk) 14:19, 5 April 2021 (UTC)