Commons talk:WikiProject Chemistry/Categories

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Nonmetal compounds[edit]

Maybe it's just me, but I'm finding myself being drawn into a revert war with User:Juiced lemon. I thought it'd be best to cool off and let an admin sort us out. The dispute is that Juiced lemon feels that Category:Nonmetal compounds is useless and is reverting every edit I make that puts a category in this bigger category. I feel that a nonmetal compounds category is not useless - I personally use it to find files all the time. As some people would, I imagine, like this category to exist, shouldn't it stay?

Media relating to each element's compounds are in a category such as Category:Hydrogen compounds. Juiced lemon is rightly subcategorising these as part of Category:Chemical compounds by element. But there's no reason why we can't simultaneously have them subcategorised under Category:Nonmetal compounds or similar broad groups of elements. However, Juiced lemon is determined not to let this happen. I'm upset about it because I've spent hours and hours making and linking all these categories, only to have them shunned by unilateral action. If the Commons chemistry community wants it this way then I'll go for that, but not just because one person likes it that way.

Could someone help?. Cheers. Ben 00:30, 17 December 2006 (UTC)

A Category:Nonmetal compounds is useless because most chemical compounds contain a nonmetal atome, even when you consider nonmetals as the chemical series (without halogens and noble gases):
Therefore, Category:Chemical compounds can be directly used.
An other issue regards categories with the form Category:X compounds (X is a chemical element); you can already browse between these categories via Category:Chemical compounds by element. Ben wants to clutter up other categories (like Category:Metal compounds) with Category:X compounds; he didn't make a scheme yet, so I would like keep an easy browsing beforehand.
Above all, the modifications Ben wishes are not a matter of urgency. We can discuss it calmly. --Juiced lemon 01:17, 17 December 2006 (UTC)
Juiced, is it true that you are reverting Ben's changes without prior discussion (before he brought it here? If true, please do not do that. If it's not a matter of urgency, why revert addition of categories at all? Discuss calmly and if there is broad consensus to do something, do it. Personally, when I read "non metal compounds" what I think of is not compounds that CONTAIN a NON metal atom, but rather compounds that do NOT contain a METAL atom. That is the usual and conventional meaning of the NON prefix. So NaCL is a metal compound since it contains Na (despite Cl being non metallic) while CH4 is not since it contains no metal atom (C and H are both non metallic). The former would not be in the category while the latter would. Hope that helps clarify the usefulness of the category and what should go in it. Juiced Lemon, you have been asked before to do better at discussing things in advance, please heed that advice. Ben, I think using the section heading "Troublesome user" may not be the best approach. I suggest a section heading that speaks to the question, not the user. How about "Nonmetal Compounds" ?? I so changed it. ++Lar: t/c 13:57, 17 December 2006 (UTC)
No, we had a discussion after I completed the Category:Chemical compounds by element, because when I did it, I removed some categories Ben had added. We are talking about categories which have not a clear definition, have not a matching article in the English Wikipedia, and are not classic chemical classes.
A very simple and indisputable way to browse throught elements or chemical compounds by element is to use a en:periodic table with links on top of category pâges. We don't need confusing categories about nonexistent chemical families. --Juiced lemon 15:07, 17 December 2006 (UTC)

Firstly, apologies to you, Juiced, for naming this section troublesome user. I think I just copied the phrase from the village pump or something. Secondly, the nonmetals are a well established chemical series. I think we should set up a Commons project on chemistry, and have it work in conjunction with the WikiProject on chemistry. It should be chemists who decide how chemistry-related media are categorised.

I agree with you, Juiced, that searching for compounds by their elements is good. But that does not mean we cannot also have them categorised by chemical series. You call this clutter, but I don't think it's a problem.

Finally, to everyone, don't get confused between compounds that don't contain a metal and nonmetal compounds. While the usage of the term nonmetal may seem confusing as it can include compounds that do contain metals, this is unfortunately how things are done in chemistry. You just have to accept it. The Commons are not here to launch a crusade against inconsistencies in chemical nomenclature. We must just reflect the terms the wider world uses. NaCl is a nonmetal compound and that is that. Get used to it!

Are there any admins who are chemists? I think they would be best placed to comment on this situation.

Again, I'm genuinely sorry to Juiced for being grizzly. As you can see, I'm trying to rebuild bridges.


Ben 16:13, 17 December 2006 (UTC)

I am no admin, and neither a chemist, but I am having some basic material science. From what I understand there are basically three kind of compounds, namely metals, compounds with an ionic binding and compounds with a vanderwaals binding. Is this what you are meaning, that compounds are basically divided by there intermolecular bindings? -- Bryan (talk to me) 16:54, 17 December 2006 (UTC)

Compounds can be categorised by their bonding, yes, but that wasn't really my point. I'll clarify a few points for you, Bryan:

  • Metals are not compounds, they are elements
  • One way of categorising compounds is by their bonding:
    • Ionic compounds are composed of ions, held together by ionic bonds (electrostatic interactions)
    • Covalent compounds are composed of atoms and are held together by covalent bonds (orbital interactions)
    • van der Waals interactions are intermolecular (act between different molecules) — they are much weaker than intramolecular interactions (forces holding together a single molecule)

The point I intended to make is this: some people will want to browse the Commons for chemical compounds organised by which chemical series their constituent atoms are from. One example of a chemical series is the nonmetals. So we should have a category called Nonmetal compounds. Yes, I know this does include most chemical compounds that exist, but that's not a problem. It is a valid part of the hierarchy of chemical nomenclature and should not be banned because Juiced lemon doesn't like it.

Ben 17:19, 17 December 2006 (UTC)

I haven't seen the term "nonmetal compounds" defined rigorously in any IUPAC book (or anywhere else for that matter), but it is, from what I've seen, loosely used to refer to compounds containing only nonmetals. However, if you want to have a category for all compounds that contain nonmetals, you could try a more explicit name such as Category:Compounds containing nonmetals. In my opinion, such a category is redundant because virtually all compounds contain nonmetals. This is because "compounds" containing only metals would typically be classified as alloys (except maybe in the gas phase), and those are more often thought of as mixtures or solutions than chemical compounds. Itub 00:43, 18 December 2006 (UTC)
I share the views and concerns of Itub and I see more added hassle than added value in Category:Compounds containing nonmetals. Maybe if I could see all the categories that would be put as subcategories of Category:Compounds containing nonmetals I might be convinced otherwise. (For what it's worth, I have 45-50 ECTS units of university studies in Chemistry.) -Samulili 14:02, 18 December 2006 (UTC)

That's a good idea, naming the cat Category:Compounds containing nonmetals. However, there are plenty of compounds that don't contain nonmetals - all compounds between metals and metalloids, such as the borides (e.g. MgB2), silicides (e.g. Mg2Si), and common semiconductors like NiAs, AlGaAs and CdTe. I think that because we have this cat called Category:Metal compounds, we should also maintain Category:Nonmetal compounds and Category:Metalloid compounds. That Category:Nonmetal compounds would contain the vast majority of all chemical compounds isn't a problem, as they'd all be subcategorized (for example, in Category:Halogen compounds.

But yes, a less ambiguous name than I originally suggested is a good idea. Let's create Category:Compounds containing nonmetals and redirect to it from Category:Nonmetal compounds.

My idea of a category of compounds containing nonmetals is one that has the main subcategories in, that is hydrogen compounds, sulfur compounds etc. Otherwise there's no category that brings together all the compounds by which nonmetal is present, and I feel that's important, as the nonmetals have similar properties and behaviour, so their compounds also have much in common.


Ben 09:11, 18 December 2006 (UTC)

This discussion should be taking place somewhere else, like Commons:Chemistry category scheme or even just Category talk:Nonmetal compounds. Noticeboards are by their nature impermanent and this issue seems like it could do with some more user input, but doesn't really need admin intervention. cheers, pfctdayelise (说什么?) 14:20, 18 December 2006 (UTC)
First, I agree with moving the discussion. Second, you are right, I neglected the metalloid compounds (although comparatively few). I just want to point out that Category:Nonmetal compounds as it currently exists is placed within Category:Inorganic compounds. That excludes most carbon compounds, so the category couldn't really be defined as "all compounds containing nonmetals". I still think the category wouldn't be very useful, but it probably wouldn't hurt either, so I could live with or without it. Itub 16:52, 18 December 2006 (UTC)


Right, to avoid constant reversion between me and Juiced lemon (we're both guilty of breaking 3RR so let's sort this out before we both get blocked), I propose the following categorisation scheme. We'll all vote on it and the policy elected will be implemented.

First, the following facts must be accepted:

As a result of these facts, I suggest we put the following categories in the following categories:

I offer the following source as proof that the nonmetals include the halogens and the noble gases:

What do you all think?

Ben 12:03, 19 December 2006 (UTC)

This is so obviously right that it shouldn't even be under discussion. Itub 13:37, 19 December 2006 (UTC)

Thanks, Itub. I think it's obvious, but Juiced lemon doesn't. What can I do? I'm not going to revert Juiced any more, my reverts just get undone. Someone sort Juiced out.

Ben 13:39, 19 December 2006 (UTC)

A table can be a piece of furniture or a landform. What are nonmetals results of the accepted meaning in a special context. We are categorizing elements and compounds by chemical series: this is a special context. To resolve this dispute, we only need a reference list of the chemical elements in the “non metals chemical series”. Since the English Wikipedia article en:Chemical series is ambiguous, I asked a peer review. Of course, I'll comply with the result of the review. --Juiced lemon 13:58, 19 December 2006 (UTC)
If you actually bothered reading en:Nonmetal or en:Periodic table, you would know the answer perfectly well. I quote: "The nonmetals are halogens, noble gases and the following elements in order of atomic number", "There are 18 naturally occurring nonmetals including the halogens and noble gases", and "Halogens and noble gases are also non-metals." Itub 14:06, 19 December 2006 (UTC)

Let me quote the Seventh edition of Material Science and Engineering - An Introduction by William D. Callister Jr., ISBN-13: 978-0-471-73696-7:

The elements positioned in Group 0, the rightmost group, are the inert gases, (...). The Group VIIA elements (F, Cl, Br, I and At) are sometimes termed the halogens. The alkali and alkaline earth metals are labeled (...) as Groups IA and IIA, (...). The elements in the three long periods, Groups IIIB through IIB are termed the transition metals, (...)

Under this text, there is a periodic table, with three clear distinctions: Metals, Nonmetals and Intermediates. What I conclude from this, is that there are metals, which itself are divided into the alkali, alkaline and transition metals, non metals, which are divided into Noble gases, Halogens and the rest.

A last note: This is not a high school book, but a well known, world wide sold, qualified book for university scholars into Engineering. -- Bryan (talk to me) 15:44, 19 December 2006 (UTC)

Also take a look at these results from google's book search: [1] and [2]. Itub 16:15, 19 December 2006 (UTC)

I'd also like to note that Juiced lemon has rewritten the category descriptions at Category:Compounds containing nonmetals and Category:Nonmetals to state that they do not involve halogens or noble gases. This is false and should be changed ASAP. I don't want to do it because I am not a neutral party. Any takers?

Ben 17:06, 19 December 2006 (UTC)

My category descriptions are not more false than yours. An universal and unique definition of nonmetals don't exist (see [3]). It's you, and not me, who wants to make categorizations founded on ambiguous notions, while they are useless to find media files. I repeated you several times that we are not writing an encyclopedia, and that categories for only educational purposes (so without practical usefulness) cannot be tolerated in Commons.
We haven't time to waste to resolve issues which are not in the scope of Commons. --Juiced lemon 17:48, 19 December 2006 (UTC)
A random website that happens to be wrong is not good evidence of anything. Commons does not need to be an encyclopedia to have correct categorization. Itub 18:02, 19 December 2006 (UTC)
(edit conflict) You've probably found that link via google, searching for "non metal" right? Well, in case you look to the other results, 3, 4, 5, 6, 8 and 9 say that hallogens and noble gases are in fact non metals. Plus this evidence is supported by the commonly used book I quoted. What my proposal is, is to have is two main subcategories, namely metals and non metals and further subcategorise in them the alkaline, alkali, transition metal, intermediates, halogens and noble gases. This is also the most useable way to find the media. -- Bryan (talk to me) 18:07, 19 December 2006 (UTC)
Bryan, I cannot find your results if you don't give the links. However, you'll not prove there is an unique way to define nonmetals:
  • here, the nonmetals in the periodic table include most of metalloids, but exclude noble gases;
  • this pdf file displays a periodic table which is similar to the table in the en.wp article en:periodic table;
  • this essay lists the 10 most common groups which divide the periodic table. Nonmetals is clearly isolated from halogens and noble gases.
So, don't try to find a rule which don't exist. --Juiced lemon 20:26, 19 December 2006 (UTC)
You are really scraping the bottom of the barrel if you need to quote websites containing what seems an essay by a high-school student, very probably based on wikipedia, and misunderstanding it in the same way as you. Try to find ONE book that says that halogens are not nonmetals. Itub 20:58, 19 December 2006 (UTC)
Try to find some authorative links. You seem to be grabbing some random links from the internet, who do not have any authority, and you seem to ignore the fact that I have given a reference in an authorative book. See also what the University of Oxford says about this.
Now what I really thing is the problem, is that the term non metal is used for two, however not contradictary things. One use is the use I gave, where non metals are all elements that are no metals nor intermediates/metalloids. However a subgroup of those nonmetals is itself also called nonmetal. Also see, the non authorative source however, wp entry:

Together with the metals and metalloids, a nonmetal is one of three categories of chemical elements as distinguished by ionization and bonding properties. The nonmetals are halogens, noble gases and the following elements in order of atomic number (nonmetals as chemical series)

So what I suggest, that we make a Non metal category, and a sub cat from that cat Nonmetals (chemical series). That is the only real solution. -- Bryan (talk to me) 21:24, 19 December 2006 (UTC)
Maybe we should wait until the debate at en:Talk:Chemical series settles. The problem is that what Juiced lemon calls the "nonmetals as a chemical series" is nothing but an artifact that sprung from the color scheme used by the wikipedia periodic table. Even that periodic table has a footnote clarifying that nonmetals don't exclude halogens and noble gases. The only correct name for the category that Juiced lemon proposes would be Category:Nonmetals that are not halogens or noble gases. Itub 22:48, 19 December 2006 (UTC)

I can't be bothered with squabbling about this issue any more. I long for the day when editors stick to topics they know and understand well, or can at least use common sense and reasonable intelligence when interpreting the quality and content sources. I'll leave it in the capable hands of you guys. I realise I could have done more productive things instead of getting in to scraps on the Commons. I'm gonna go make some images and upload them to whatever category is in fashion at the time!

Thanks for the memories!

Ben 00:55, 20 December 2006 (UTC)

At the momment, Category:Nonmetals in Commons is linked to en:Category:Nonmetals in the English Wikipedia. Both are for elements in the chemical series nonmetals.
I agree to change the category name (for the chemical series) only if the matching category is renamed beforehand in the English Wikipedia.
Though I think it's an useless category, I'll not oppose another “Nonmetals” category regarding Any of a number of elements, such as oxygen or sulfur, that lack the physical and chemical properties of metals. Of course, the name of this category must be different than the name of the category for the chemical series “nonmetals” in the English Wikipedia.
Notice that, following my request (for a peer review), the notion of chemical series is currently disputed in the English Wikipedia. It's a problem, since “chemical series” is a standard feature in the table (en:template:Elementbox_series), used for each chemical element (see en:Carbon).
I suggest to wait for a solution regarding the issue in the English Wikipedia. --Juiced lemon 23:21, 22 December 2006 (UTC)

Category:Hazard symbols[edit]

Category:Hazard symbols should be moved to Category:Hazard symbols of chemistry: precise title (I accidentially added the new category), or we could separate into ECB, WHMIS

Category:Hazard symbols could be redirected to general Category:Safety labels

greetings --W!B: 03:48, 12 January 2007 (UTC)

What about Category:Chemical hazard symbols? --Leyo 17:17, 14 January 2009 (UTC)
Category:Hazard symbols of chemistry and Category:Chemical hazard symbols > the symbols are not hazard, but
the chemicals are hazard: So the correct name would be Category:Symbols of harzard chemicals.
de:user:dr.cueppers Dr.cueppers (talk) 14:41, 27 February 2009 (UTC)
“Symbols of hazard chemicals” does not give any results in Google, whereas “Chemical hazard symbols” gives a lot of results. --Leyo 15:24, 27 February 2009 (UTC)
"Symbols of hazard chemicals" sounds somehow wrong. Grammatically correct would be "hazardous chemicals", but this can be confused with images for the chemicals which are hazardous. "Chemical hazard symbols" is unambiguous. Matt (talk) 08:33, 17 April 2009 (UTC)

The category was not moved to Category:Chemical hazard signs. --Leyo 22:20, 10 October 2011 (UTC)

Skeletal formulae[edit]

Is there any benefit in keeping Category:Skeletal formulae? As it stands, there are too many images there, which would be much better off in their own categories.


Ben (talk) 15:22, 26 July 2008 (UTC)

I agree with Ben. Presently, the category even contains structures with –CH3 moieties drawn. --Leyo 17:13, 14 January 2009 (UTC)

Commons:Categories for discussion/Current requests/2009/02/Category:Skeletal formulae --Leyo 23:44, 25 February 2009 (UTC)

Deleted --Leyo 14:22, 3 March 2009 (UTC)

Category:Periodic Table and Category:Periodic table[edit]

I guess Category:Periodic Table was created by accident. By the way, Category:Periodic table might require more subcategories for the periodic table construction kit used on English Wikipedia. Matt (talk) 08:27, 17 April 2009 (UTC)

I moved all the images to Category:Periodic table and redirected Category:Periodic Table there. Edgar181 (talk) 11:51, 17 April 2009 (UTC)

Category:Media needing chemical classification[edit]

I added some files to that category as I cannot do the correct categorization myself. Cheers 20:43, 17 April 2009 (UTC)

Category:Name reactions[edit]

Several files are categorized in Category:Name reactions as well as Category:Organic reactions. Why not just recategorizing Category:Name reactions to be a subcategory of Category:Organic reactions instead of Category:Chemical reactions? --Leyo 23:30, 25 February 2010 (UTC)

Or what about creating a new subcat Category:Organic name reactions? --Leyo 16:58, 10 March 2010 (UTC)
I've only read the term "name reactions" in the context of organic chemistry. I guess there must be reactions in other branches of chemistry name after people (I can't think of any off the top of my head), but are they properly referred to as "name reactions" or does the phrase imply "organic"?
Ben (talk) 14:54, 13 March 2010 (UTC)
Belousov–Zhabotinsky reaction or Briggs–Rauscher reaction maybe? In de-WP, the are in the category Kategorie:Namensreaktion. --Leyo 00:55, 14 March 2010 (UTC)
I thought it might be the case. Only being a student, maybe some other WP chemists can give a more reliable opinion!
Either way, I agree we should change the categories.
Ben (talk) 02:59, 14 March 2010 (UTC)
Category:Name reactions should be used as in the de:Wikipedia, both for organic and inorganic chemistry. On the other hand The Merck Index. An Encyclopaedia of Chemicals, Drugs and Biologicals. 14. Ed., 2006, ISBN 978-0-911910-00-1 uses the term ORGANIC NAME REACTIONS. --Jue (talk) 11:45, 25 March 2010 (UTC)
Does this mean that creating a subcategory Category:Organic name reactions as I proposed above it a good idea? --Leyo 13:07, 25 March 2010 (UTC) PS. Google hits

I think so. Do it :)

Ben (talk) 14:21, 26 April 2010 (UTC)

Plurals and derivatives[edit]

This has been bugging me for a while. Categories containing chemicals formally derived from a parent compound - what should we name them. Right now there's a great inconsistency between categories named after the plural of the parent compound, and categories that are named as derivatives of the parent compound. E.g. we have Category:Benzene derivatives but we also have Category:Pyridines. We have Category:Benzoic acids but we also have Category:Aniline derivatives. I could list more, but you get the point. We should agree on a naming scheme for all of them. This may sound like nitpicking, but it is important in defining more clearly what should go inside each category. Ephemeronium (talk) 00:42, 2 June 2011 (UTC)

I agree that this is an important unsolved issue. What if we used the plural category names just for different isomers (example: Category:Hexabromocyclododecanes). For all the rest like substituted compounds, we take “XXX derivatives”. --Leyo 00:59, 2 June 2011 (UTC)

So, new category names would include 'Benzoic acid derivatives', 'Pyridine derivatives', etc. That works for many, but something doesn't sound right about 'Chlorobenzene derivatives', 'Trichlorobenzene derivatives', or even 'Monochlorobenzene derivatives'. I don't like the latter because it implies 'monochlorobenzene' is something different from 'chlorobenzene'.

Also, what do we do with the parent compound? At the moment Benzoic acid is neatly categorized under Benzoic acids, but this would make no sense under the derivatives naming scheme. It can't be a derivative of itself, surely. Is there a better word than 'derivatives' we can use?

I don't like long category names either. Most of the Wikipedias are using the plural naming scheme. I prefer it unless we can think of a better alternative. Ephemeronium (talk) 14:10, 2 June 2011 (UTC)

Category:Dehydratation reactions and Category:Dehydration reactions[edit]

Mein Englisch ist nicht so gut, dass ich auf Englisch schreiben kann. Ich hoffe, ihr werdet mein Anliegen trotzdem verstehen: Vor einigen Tagen habe ich die Kategorie Category:Dehydration reactions angelegt und benannt nach dem englischen Eintrag en:Dehydration reaction. Jetzt sehe ich, dass es schon die Kategorie Category:Dehydratation reactions gab. Vielleicht können beide Kategorien zusammengelegt und ein Redirect angelegt werden. --Hystrix (talk) 20:36, 30 June 2011 (UTC)

It seems that both terms are existing, but the second one (dehydration) is much more common. I emptied the first category in the second one. Rhadamante (talk) 03:10, 1 July 2011 (UTC)
Thank you for your quick response. Hystrix (talk) 09:59, 1 July 2011 (UTC)

Anti-cancer drugs[edit]

What is the difference between Category:Antineoplastic agents and Category:Chemotherapeutic agents? Currently the former is a subcategory of the latter. But as far as I am aware they are both synonyms for 'anti-cancer drugs'. Should they be merged? Ephemeronium (talk) 15:12, 18 September 2011 (UTC)

I am not expert in this field. Such persons might be found at en:WT:PHARM. --Leyo 07:39, 19 September 2011 (UTC)