Wikipedia:Manual of Style/Chemistry/References and external links

When to cite
Citations should be used whenever non-obvious information is presented.

What to cite
General properties and characteristics should cite textbooks or reviews. The primary literature (journal articles) should be cited only where tertiary or secondary sources do not exist, or are inadequate. They should be used to illustrate examples, not to justify general statements, as their interpretation can lead to problems with our neutral point of view policy: they can also be difficult for the general reader to access. Some occasions where it is normal practice within Wikipedia chemistry to cite the primary literature include:
 * the first report of a discovery/synthesis of a (compound, reaction, etc.), if the citation is known;
 * the report of a crystal structure determination, if we have used the atomic coordinates to create the picture (the citation may go on the image description page);
 * IUPAC recommendations for chemical nomenclature and other terminology.

The secondary literature includes review articles, monographs, chemical encyclopedias and specialist textbooks. The use of the available secondary literature is strongly recommended to reference information on chemical safety, in preference to either (primary) journal articles or (tertiary) generalist textbooks: see Manual of Style (chemistry)/Safety for more details and examples of secondary sources. Organic Syntheses and Inorganic Syntheses are considered to be secondary sources rather than primary sources.

Websites are normally not considered authoritative but are sometimes appropriate. A few websites which are well regarded include: The official websites of various government bodies (e.g. NIST) can often provide useful information as well.

How to cite
The style of inline citations is to be used throughout chemistry and chemicals articles, preferably using citation or similar citation templates, although this is not mandatory. For papers published in Organic Syntheses, there is a special citation template (OrgSynth), which is simpler to fill in.

Citation templates have been created for a number of commonly used textbooks: some examples are given below, and the complete list can be found at Category:Chemistry citation templates. Please include page numbers or page ranges (page =  or pages =  parameters respectively) when using these templates. If you create a new template, please remember to categorize it in Category:Chemistry citation templates (so that others can find it and use it), and to make the name of the template specific for the edition of the textbook which is cited (to avoid future cleanup problems).