Wikipedia:Manual of Style/Chemistry/Compound classes
|Manual of Style|
Many articles discuss classes of compounds. Articles on compound classes do not feature a chembox. Scope:
- Ions including the notable conjugate acids and bases, distinct from the parent base and acid. Separate articles are also warranted on certain oxidized or reduced derivatives of elements or neutral molecules. Examples: chloride, oxide, nitrate, triflate.
- Functional groups. Examples: alcohols, aldehydes, carboxylic acids.
- Classes of compounds. Examples: steroids, chlorofluorocarbons, and metal carbonyls.
The lede of the article should introduce the class of compound, noting general characteristics, uses (e.g. drugs, explosives, pesticides, fuels). Ordinarily, specific points are discussed within the article body.
Structure and bonding
Information about the bond lengths and angles typical of the compound class, energetics of conformational and rotational barriers, configurational stability. Description of the bonding employing models such as hybridization and molecular orbitals. Bond dissociation energies.
For simple organic compounds where the nomenclature is relatively easy, mention should be made of systematic (IUPAC) nomenclature. Historical and popular alternate naming conventions are often appropriate. Compound classes with specific conventions include steroids, sugars. Conventions for 2-D structures should also be discussed, such as the Haworth and Fisher projections for sugars. Remember, the article is about chemistry, not naming, so this section should not be long.
For organic compounds, comparisons with other classes of compounds are useful with regard to acidity/basicity, melting/boiling points, solubility, color, odor, etc. Non-generic methods that useful characterize this specific class of compounds, e.g.,usual ranges for NMR chemical shifts and IR bands. Classic qualitative "wet" analyses, flame tests, and other kinds of analysis.
Occurrence and (possibly) applications
When applicable, the natural occurrence and biochemistry should be summarized. Prominent nutritional and medical applications should be mentioned since readers are often interested in how classes of compounds affect their health.
Many inorganic compounds exist as important minerals (minor minerals should not be highlighted in the overview article - almost all salts are observable as secondary minerals). Numerous molecules and ions occur in the interstellar medium. The interaction of the compounds with the environment should be mentioned, including aspects of pollution and biodegradation.
General applications should be briefly described, e.g. alkenes for making polymers, lower alcohols as solvents, hydroxides as bases. Major industrial applications usually receive priority, since large-scale applications affect the readership most strongly, for good or for worse. Laboratory applications are also valuable, although they are also discussed in the reactions section.
Pictures of prominent members of the class of compounds are often useful, and the inclusion of images improves the readability of the article by breaking up the prose.
For organic compounds and functional groups, describe the main synthetic routes to this class. In the early development of an article, lists are almost inevitable. For more mature articles, the description of reactions should be organized by themes, e.g., oxidation, reduction, hydrolysis. Chemists remember reactions by their names, but many readers do not. Thus, named reactions should be secondary to the theme or logic of the reaction. The sequence of presentation should roughly mirror their significance. Specific illustrative examples can usefully be drawn from Organic or Inorganic Syntheses.
Factors affecting reactivity should be discussed. For example under aromatic compounds, it would be useful to discuss the Friedel-Crafts reaction. A survey of the possible functional group interconversions is appropriate here. Try to avoid lists: group them by similarity, with an appropriate theme as the header.
If notable, the first discovery or the first major use of this class of compounds can be discussed. Obviously, this section need not apply for many classes.
Typically, compound classes do not have a section on safety since the range of issues can vary widely. Exception is made when most members of a class share a hazard - e.g. azides tend to be reactive/explosive, and arsenates tend to be toxic. The anatomical consequences of a safety issue are rarely appropriate. If there is nothing to be said, nothing should be said! WP should not be alarmist.
- G. P. Moss (1989). "Nomenclature of Steroids (Recommendations 1989)" (PDF). Pure & Appl. Chem. 61 (10): 1783–1822.