Wikipedia:WikiProject Chemicals/Style guidelines

From Wikipedia, the free encyclopedia

These guidelines have been put together by the WikiProject Chemicals to help editors improve the 4000 or so articles on Wikipedia which are about chemical compounds.

Contents

[edit] Title

There is a misconception among certain editors that the title of a chemical compound article must be the systematic name of the compound: this is not always the case.

[edit] General rule

From Wikipedia:Naming conventions:

"Generally, article naming should give priority to what the majority of English speakers would most easily recognize, with a reasonable minimum of ambiguity, while at the same time making linking to those articles easy and second nature."

[edit] IUPAC preferred name vs. systematic name

IUPAC recommends [1] the use of non-systematic names for some organic compounds, and these recommendations should be followed in article titles. Examples:

Acetic acid not Ethanoic acid
Toluene not Methylbenzene
Lysine not 2,6-Diaminohexanoic acid

[edit] Element names

Traditionally, the names of three elements have been spelt differently in US and British English. With the onset of computer searching of databases, it was felt necessary to standardize these spellings as follows:[2]

Aluminium not Aluminum
Sulfur not Sulphur
Caesium not Cesium

These international standard spellings should be used in all chemistry-related articles on English Wikipedia, even if they conflict with the other national spelling varieties used in the article." These are based on "preferred names" in IUPAC nomenclature.

[edit] Use of Stock nomenclature

Stock nomenclature for inorganic compounds is based on the indication of the oxidation number (as a Roman numeral, in parentheses) of each of the major elements in the compound, e.g. iron(III) chloride. It is widely, if sometimes incorrectly, used on Wikipedia for the titles of articles about inorganic compounds. It is not obligatory, as there are other acceptable methods for naming these compounds, but it is often preferred as the most common non-ambiguous name for a substance. The following guidelines are based on current WikiBestPractice:

  1. Only the cationic element (i.e. the element whose name appears unchanged in the compound name) is assigned its oxidation number. Except in rare cases (none at present), we do not assign the oxidation number in the anion: hence potassium permanganate not potassium manganate(VII), sodium hypochlorite not sodium chlorate(I).
  2. There is no space between the end of the element name and the opening parenthesis: hence silver(I) fluoride not silver (I) fluoride. Note that this is an exception to the usual English style for parentheses.
  3. It is not necessary to specify the oxidation number when there is no possibility of ambiguity in the compound title: hence sodium chloride not sodium(I) chloride.
  4. Stock nomenclature should only be used for ionic compounds. Compounds with a substantial degree of covalancy should be named by stoichiometric nomenclature: hence titanium tetrachloride not titanium(IV) chloride.
  5. Stock nomenclature should not be used for compounds with mixed or non-integral oxidation numbers: hence triiron tetraoxide not iron(II, III) oxide (in fact, this article is difficult to name and, as an exception, redirects to magnetite).

[edit] Drug-related articles

See also WikiProject Drugs
Where a compound has a WHO International Nonproprietary Name (INN), this should be used as the article title.

[edit] Prefixes

For technical reasons, it is not recommended to use non-numerical prefixes in article titles. This includes:

Positional identifiers ortho-, meta-, para-, α-, β-, γ-
Stereochemical identifiers cis-, trans-, (E)-, (Z)-
Chiral identifiers (R)-, (S)-, D-, L-, (+)-, (−)-

Note that iso in such compounds as isopropanol is not only permitted but recommended. No hyphen is used in these cases. sec- and tert- are hyphenated and non-capitalized, and should be avoided if possible on Wikipedia.

When the chosen aticle title starts with a number, the first letter of the compound name should be capitalized: hence 1,1,1-Trichloroethane not 1,1,1-trichloroethane. A redirect from the uncapitalized version should be created to simplify linking from other articles. See also Capitalization below.

[edit] Redirects

From Wikipedia:Deletion policy: "Don't worry, redirects are cheap."

Redirects should be created for:

  • Alternative names for the compound, including acronyms where appropriate;
  • Alternative capitalizations, where there is a numerical prefix in the article title.

[edit] Exceptions

Even with the best will in the world, no set of guidelines can cover every case. Some articles on Wikipedia have non-standard titles through consensus that this is the most commonly used name (in scientific circumstances) for the compound concerned, whatever IUPAC or the other rules suggest. For example:

Ethylene oxide not oxirane
Phosphine not phosphane (and for substituted phosphines, arsine and stibine)
Wilkinson's catalyst not chlorotris(triphenylphosphane)rhodium
Vaska's complex not carbonylchlorobis(triphenylphosphane)iridium

Please do not get into revert wars over the naming of an article: the best place for discussion is on the article's talk page or (failing that) at Wikipedia talk:WikiProject Chemicals.

[edit] Article format

[edit] Infobox

Wikipedia:WikiProject Chemicals strongly recommends the use of chemical infoboxes for the following reasons:

  • If basic (often numerical) data is included in the article text, the readability of the article is reduced.
  • They reflect a certain consensus as to what data is appropriate for an encyclopedic article.
  • They promote a common visual style among Wikipedia articles on a given subject area.
  • They are well supported by the MediaWiki software (unlike HTML tables), and easily adapted (by individual editors) to the different needs of different articles.

Three chemboxes are currently available:

To include a chembox in an article:

  1. Edit the article to include {{subst:chembox}} (or {{subst:chembox simple inorganic}} or {{subst:chembox simple organic}}, as appropriate) as the first line of the article source code.
  2. Save your edit with the Edit summary "Chembox added".
  3. Re-edit the article to fill in the spaces in the infobox, and to make whatever other changes are necessary for the particular compound.

For formatting reasons, the code for the infobox should be at the very beginning of the source code.

[edit] Introductory paragraph

See also: Wikipedia:Lead section

[edit] Preparation

All articles about chemical compounds should include one or more methods of preparation:

  • laboratory-scale preparation
  • industrial production
  • biosynthesis

as appropriate. Even articles about chemicals which are normally extracted from minerals (e.g. molybdenum disulfide) should normally have a laboratory route to the same compound.

[edit] Uses and/or reactions

[edit] Other sections

[edit] Occurrence

[edit] History

[edit] Toxicology

[edit] Safety

The hazards associated with a chemical compound are an integral part of the description of that compound.

Two main rules:

  • The description of hazards should avoid speculation. This is partly an extension of Wikipedia NPOV policy, but not entirely. There is no need to include a section which merely states "all chemical compounds should be treated with the utmost precaution": such a section tells the reader nothing. If there are no known (or reasonably suspected) hazards, there is nothing for Wikipedia to say.
  • The description of hazards should avoid hyperbole. The role of Wikipedia is to give balanced and accurate information, to allow its readers to reach their own conclusions.

Descriptions of hazards should, as far as possible, be based on published, peer-reviewed sources (which should, of course, be cited at the appropriate point in the article). A list of resources for chemical safety information is given in the external links section of these guidelines.

[edit] Suppliers

[edit] See also

[edit] References

See: Wikipedia:Footnotes, Wikipedia:Cite your sources

References should come in a numbered list immediately before the External links section. If footnotes are also used, these should be interspersed with the references and the heading changed accordingly. Notes and references should be numbered sequentially throughout the article by superscript Arabic numerals.

The use of automatic footnote numbering is encouraged: it is undoubtedly more time-consuming to enter at first, but it simplifies subsequent revisions and helps to avoid referencing errors. Multiple referencing to the same footnote is now possible with the {{ref label}} and {{note label}} templates.

There is no consensus in Wikipedia as a whole for the format of the references, although APA style is suggested as a guideline: this is almost identical to the style used in ACS journals such as J. Am. Chem. Soc. Wikipedia offers a number of citation templates which reproduce this style.

Some commonly used textbook have their own citation templates:

Template Reference
{{Cotton&Wilkinson4th}} Cotton, F. Albert; Wilkinson, Geoffrey (1980). Advanced Inorganic Chemistry (4th Edn.). New York:Wiley. ISBN 0-471-02775-8.
{{Cotton&Wilkinson6th}} Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999). Advanced Inorganic Chemistry (6th Edn.) New York:Wiley-Interscience. ISBN 0-471-19957-5.
{{Greenwood&Earnshaw}} Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.). Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.
{{March4th}} March, J. (1992). Advanced Organic Chemistry (4th Edn.), New York:Wiley. ISBN 0-471-60180-2
{{McMurray}} McMurray, J. (1992). Organic Chemistry (3rd Edn.), Belmont:Wadsworth. ISBN 0-534-16218-5
{{Merck12th}} Merck Index (12th Edn.)
{{RubberBible53rd}} Weast, R. C. (Ed.) (1972). Handbook of Chemistry and Physics (53rd Edn.). Cleveland:Chemical Rubber Co.
{{RubberBible83rd}} Lide, D. R. (Ed.) (2002). CRC Handbook of Chemistry and Physics (83rd Edn.). Boca Raton (FL):CRC Press. ISBN 0-8493-0483-0.
{{RubberBible86th}} Lide, D. R. (Ed.) (2005). CRC Handbook of Chemistry and Physics (86th Edn.). Boca Raton (FL):CRC Press. ISBN 0-8493-0486-5.
{{Stryer}} Stryer, L., J. M. Berg and J. L. Tymoczko (2002). Biochemistry, 5th Ed., New York: W. H. Freeman. ISBN 0716746840.

Searchable text
{{VogelOrganic}} Furniss, B. S.; Hannaford, A. J.; Smith, P. W. G.; Tatchell, A. R. (1989). Vogel's Textbook of Practical Organic Chemistry (5th Edn.), Harlow:Longman. ISBN 0-582-46236-3
{{VogelQualitative}} Svehla, G. (1979). Vogel's Textbook of Macro and Semimicro Qualitative Inorganic Analysis, London:Longman. ISBN 0-582-44367-9
{{VogelQuantitative}} Mendham, J.; Denney, R. C.; Barnes, J. D.; Thomas, M.J.K.; Denney, R. C.; Thomas, M. J. K. Vogel's Quantitative Chemical Analysis (6th Edn.) New York:Prentice Hall. ISBN 0-582-22628-7.

[edit] External links

A certain number of frequently used sites have their own templates for the external link:

Template Link
{{ecb}} European Chemicals Bureau
{{nist}} NIST Chemistry WebBook
{{ICSC|xxyy|xx}} International Chemical Safety Card xxyy
{{inrs}} Institut national de recherche et de sécurité ({{{year}}}). "{{{title}}}." Fiche toxicologique n° {{{number}}}. Paris:INRS. (PDF file, in French)
{{PubChemLink|xxx}} CID xxx from PubChem
{{SDBS}} SDBS spectral database
{{webelements}} WebElements

[edit] Categories

[edit] Interwiki links

[edit] Articles from other WikiProjects

[edit] WikiProject Drugs

[edit] WikiProject Elements

[edit] WikiProject Rocks and Minerals

[edit] WikiProject Polymers

[edit] Other topics

[edit] Capitalization (English language convention)

The names of chemical compounds are common nouns. They are capitalized at the beginning of a sentence or title, but not elsewhere. The names of chemical elements are also common nouns in English, and are NOT capitalized when written out as words. They retain capitalization as chemical element symbols. There is no more reason to capitalize uranium (symbol U) than carbon (symbol C), or uranium-235 than carbon-14. The convention that elements are common nouns includes even elements derived from proper nouns, such as places or the names of persons. Thus einsteinium (Es) and californium (Cf) are capitalized only in symbol. Please see IUPAC Provisional Recommendations for the Nomenclature of Inorganic Chemistry (2004). The element mercury is not capitalized, but the word when referring to a place (the planet Mercury), the Roman god Mercury, the Ford Mercury automobile, etc., is capitalized as a proper noun.

Prefixes such as sec-, tert, ortho-, meta-, para- and the numerical prefixes are not considered part of the name: the first letter of main part of the name should still be capitalized where appropriate. The exception is iso-, which is part of the name and therefore not italicized or hyphenated. Substituent groups do form part of the name: hence the correct article title is 1,2-Dichloroethane, which is written as 1,2-dichloroethane if not at the start of a sentence. Note that the two wikilinks refer to separate articles: one is a redirect to the other.

[edit] Special symbols

[edit] Greek letters

The following codes are available for inserting Greek letters into articles. Greek letters are never italicized.

α α Α Α
β β Β Β
γ γ Γ Γ
δ δ Δ Δ
ε ε Ε Ε
ζ ζ Ζ Ζ
η η Η Η
θ θ Θ Θ
ι ι Ι Ι
κ κ Κ Κ
λ λ Λ Λ
μ μ Μ Μ
ν ν Ν Ν
ξ ξ Ξ Ξ
ο ο Ο Ο
π π Π Π
ρ ρ Ρ Ρ
σ σ Σ Σ
τ τ Τ Τ
υ υ Υ Υ
φ φ Φ Φ
ψ ψ Ψ Ψ
χ χ Χ Χ
ω ω Ω Ω

[edit] Arrows

The right arrow → and the equilibrium sign ⇌ are available from the codes → and {{unicode|⇌}} respectively. The use of the {{unicode}} template is recommended for ⇌ because of a bug in some versions of Internet Explorer. The equivalent left-facing signs are ← (←) and ⇋ ({{unicode|⇋}}).

The double-headed arrow ↔ for canonical forms is available from the code ↔.

[edit] Other symbols

  • The center dot for hydrates etc. is available from the code ·.
  • The minus sign (longer than a normal hyphen) is available form the code − but does not reproduce well on some versions of Internet Explorer.
  • The multiplication sign × (e.g. for powers of ten) is available from the code ×.
  • The symbols for Planck's constant, ℎ and ℏ, are available from the codes {{unicode|ℎ}} and {{unicode|ℏ}}: the use of the {{unicode}} template is recommended because of a bug in some versions of Internet Explorer.

[edit] Chemical structures and reaction schemes

The settings for structures and 3D representations is being organised on a separate structure drawing guidelines page, after consensus is agreed by the structure drawing workgroup.

Commons
Wikimedia Commons has more media related to:

[edit] General

  • Please do not scan diagrams from books or other paper sources. Such scanned images are usually of low quality, and may be in violation of the original copyright. Images should be prepared with a molecule editor: there are freeware molecule editors available for download.
  • WikiTeX allows to you edit chemical structures directly in your wiki articles, producing publication-ready PNGs.
  • Images may be uploaded in .jpg, .gif or .png format. We find that .PNG files reproduce the best, but not all users are able to prepare them.
  • Please prepare your images much larger than the final size. Chemical structures and reaction schemes compress to very small files compared with photos. If the original image is too small or at too low a resolution, the reproduction will be pixelated on the web or on printouts.
  • Please do not include text in your images. Text tends to reproduce very badly in the resizing of images, and images with English language text cannot be used by other Wikipedias. Please do not use the abbreviation Me for CH3: no space is saved, and there is a risk of ambiguity with the German abbreviation for Metall (metal).
  • Please ensure that your images are legible at either 250 pixel width (half-page) or 600 pixel width (full-page). Images that can be reduced to 250 pixel width (or lower) are preferred, as this simplifies the page formatting.

[edit] Suggested molecule editor settings

  • Line width: 0.107 cm
  • Bond length: 2.566 cm
  • Bond angles: fixed at 15° or 30°
  • Font: Arial 45 pt

[edit] Image processing

Most molecule editors cannot produce .PNG images directly. The image processing step also allows a canvas (margin) to be added (this is usually absent from the molecule editor output).

  • Save as: TIFF black/white bitmap.
Image processing (Photoshop or Irfan view):
  • Add canvas of 75 pixels to all four sides (Photoshop: Image:Canvas Size, relative, 150 pixels width, 150 pixels height)
  • Save as a PNG black/white bitmap.

[edit] Uploading and copyright

WikiProject Chemicals encourages users to upload their images to Wikimedia Commons. This enables images to be used in other wikimedia projects without duplicating the file (and so wasting disk space). It is also simpler to find images in the Commons category structure than on English Wikipedia. To upload images to Commons, you must be a registered user there: you may use the same username as on English Wikipedia (indeed, this is recommended).

Chemical structures and reaction schemes are assumed to be copyright. There are a few exceptions, but it is unreasonable to expect the non-chemists on copyvio patrol to recognise them. Uploaded images must have a copyright tag: either {{PD-self}} if you release the image into the public domain or {{GFDL-self}} if you release it under the GFDL. Images released under "non-commercial use only" licences are no longer accepted on Wikipedia and will be deleted without warning. Images without a tag may also be deleted.

The following template may be used for the image description file:

* '''Description''': Chemical structure of [[:en:???|???]].
* '''Author, date of creation''': selfmade by [[:en:User:???|???]] on [[????-??-??]].
* '''Source''': user-created image
* '''Copyright''': [[:en:GNU Free Documentation License|GNU Free Documentation License]]. (GFDL)
* '''Comments''': high-resolution b/w PNG; ChemDraw / Photoshop.


{{GFDL-self}}


[[Category:Chemical structures]]

Please do not forget to include a category in the image description file if you are uploading to Commons.

[edit] Units

Only metric units of the SI systems should be used. Values with units should be separated with  . Examples include:

  • Diameter of New York: 43 km
  • Surface of a coin: 6.5 cm2
  • Very cold: 263 K or also −10 °C
  • Sirupy: 10 Pa·s
  • Right angle: 90° (isn't a unit, so no  )

[edit] Experimental details

[edit] See also

[edit] References

  1. ↑ Panico, R.; & Powell, W. H. (Eds.) (1994). A Guide to IUPAC Nomenclature of Organic Compounds 1993. Oxford: Blackwell Science. ISBN 0-6320-3488-2.
  2. ↑ Leigh, G. J. (Ed.) (1990). Nomenclature of Inorganic Chemistry. Recommendations 1990. Oxford: Blackwell Science. ISBN 0-6320-2494-1.

[edit] External links

[edit] Nomenclature

[edit] Properties

[edit] Safety information

[edit] Suppliers

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