Wikipedia:Manual of Style/Chemistry/Chemicals

Articles under the Chemicals wikiproject should have the following general layout:

Infobox

The appropriate infobox to use is {{Chembox}}. It is a modular, expandable infobox. Just use the parameters which you need; empty values will not be displayed. Chemboxes should be used for 'all chemical compounds, so long as they can exist in that form, even for compounds which are not isolable in pure, solvent-free form (e.g. hypochlorous acid). Chemboxes should not be used for ions, polymers, and proteins and enzymes (except simple peptides).

To include a chembox in an article:

Open {{Chembox}} and copy the relevant (simple, medium, full) box desired, and paste into a text editor
Open the relevant reference (e.g. MSDS, Merck Index, CRC Handbook, etc.) and input the data into the template
Copy the filled-out template into the relevant Wikipedia article.

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

Introductory paragraph

See also: Wikipedia:Lead section

Introductory paragraph should classify the compound either generally (organic compound vs inorganic compound) or more specifically (e.g., organometallic compound or organoarsenic compound). A few properties should be described, assuming STP and noteworthy features mentioned (e.g. extreme toxicity, odor, hygroscopicity). For simpler organic compounds, the main functional group is mentioned, whereas for complex molecules, a parent molecule should be mentioned. Alternative names and routine properties (m.p., density) are ordinarily placed in the Chembox, not in the lede.

Properties

This section is often not needed. A discussion of properties is more important for chemicals encountered in everyday life and for solids, where “collective" properties (magnetism, hardness, conductivity) are important. The properties of small organic molecules can be surmised from data in the Chembox and generally do not require extended discussion. Often this section is combined with a description of structure, which summarizes the molecular structure and/or crystal packing (for extended solids). Bond distances are quoted in picometers or angstroms.

Occurrence

If the compound occurs naturally, it can be mentioned here. If natural sources are industrially significant, some discussion should be included. Avoid one-sentence sections — such data can be left in the lead.

Preparation

Articles about chemical compounds should include methods of preparation, usually in this order:

industrial production. Production figures give readers a sense of the commercial significance of a compound.
biosynthesis
laboratory-scale preparation

Different methods of synthesis/production may merit full-fledged subheadings. Even articles about compounds that are normally extracted from minerals (e.g. molybdenum disulfide) should ideally have a laboratory route to the same compound. Mention should be made if a compound is routinely available commercially.

Where appropriate, the first synthesis/first characterization of each compound should be mentioned and referenced to the original article. Apart from that, "foolproof" syntheses such as those listed in Organic Syntheses and Inorganic Syntheses are preferred. Patented syntheses should be phrased carefully — e.g. "xxx may be synthesized from ... " Patents are usually inferior sources owing to their undependable reliability, accessibility, and clarity.

When writing about preparations, remember that Wikipedia is not a manual or textbook. In general, preparations should be described in general terms, not as step-by-step instructions giving specific amounts, times, conditions, equipment, and details such as methods of stirring and separation.

Uses and/or reactions

The order of presentation and allocation of content should reflect the scale of the individual applications. Large-scale applications should be listed first. Lay editors will naturally tend to enumerate domestic uses. Wikipedia does not aspire to report all niche uses. Avoid lists: try to group the various uses by similarity into a coherent paragraph. If the application stands alone, the application is either significant enough to merit a paragraph to itself, or insignificant enough not to deserve mention.

If reactions are to be described, emphasize the well established reactions (e.g. those in Organic and Inorganic Syntheses). Highly specialized reactions that are neither broadly applicable nor illustrative are inappropriate.

History

This paragraph, which is optional, should include the discovery/first synthesis of this compound. Past industrial processes can be described as well. If the etymology of the compound is complicated, it can be included here as well, instead of in the lede.

Safety

The majority of compounds are described by a long list of potential hazards as well as R&S phrases. Even innocuous chemicals such as sodium chloride have risk and safety phrases: R36, S26, S36 in their MSDSs. Wikipedia does not aspire to be an MSDS. The hazards associated with a chemical compound should ordinarily be described in the Chembox (via EUClass, NFPA, or MainHazard parameters; further elaborated in R and S phrases). The information in the Chembox is sufficient for most compounds. News reports of routine accidents, even though they may be tragic, are usually not relevant.

Three main rules:

If the hazards are relatively obvious (e.g. hexafluorophosphoric acid is a strong acid, and should not be stored with bases and reactive metals) do not create a separate sub-section here.
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.

Toxicology

Depending on the extent and nature of the information, toxicological content may be incorporated into the Safety section or it may be a separate. If the compound is a drug, follow Wikipedia:WikiProject Drugs' recommendations.

Suppliers

Wikipedia is not a buyer's guide. Do not include suppliers' information as they are spam magnets. Such lists are unmaintainable and cause problems. If, however, a particular compound is produced by only one or two suppliers, the suppliers names might be relevant.

Current events

From WP:NOT#JOURNALISM:

Journalism. Wikipedia should not offer first-hand news reports on breaking stories. Wikipedia is not a primary source. However, our sister project Wikinews does exactly that, and is intended to be a primary source. Wikipedia does have many encyclopedia articles on topics of historical significance that are currently in the news, and can be updated with recently verified information.

Accidents and incidents occur all the time. While their scale and magnitude may merit inclusion in Wikipedia on grounds of notability, that such an accident has occurred is not sufficient justification for inclusion in the context of an article about chemicals. Wikipedia does not attempt to dispense advise on what to do in the event of a (...) incident, either. (See WP:NOTGUIDE) Historic accidents and incidents may only be contextualized in the discussion on the specific hazards of certain chemicals, without serving as case studies in itself. To reiterate, if such accidents are sufficiently notable, they should have their own article (e.g. discussion in Bhopal disaster, not in methyl isocyanate).