Chemical nomenclature

The nomenclature used most frequently worldwide is the one created and developed by the International Union of Pure and Applied Chemistry (IUPAC).

These "color books" are supplemented by specific recommendations published periodically in the journal Pure and Applied Chemistry.

However, the American Chemical Society's CAS numbers nomenclature does not represent a compound's structure.

It is generally understood that the purposes of lexicography versus chemical nomenclature vary and are to an extent at odds.

These differing purposes can affect understanding, especially with regard to chemical classes that have achieved popular attention.

Examples of the effect of these are as follows: The rapid pace at which meanings can change on the internet, in particular for chemical compounds with perceived health benefits, ascribed rightly or wrongly, complicate the monosemy of nomenclature (and so access to SAR understanding).

Opinions differ about whether this was deliberate on the part of the early practitioners of alchemy or whether it was a consequence of the particular (and often esoteric) theories according to which they worked.

While both explanations are probably valid to some extent, it is remarkable that the first "modern" system of chemical nomenclature appeared at the same time as the distinction (by French chemist Antoine Lavoisier) between elements and compounds, during the late eighteenth century.

The French chemist Louis-Bernard Guyton de Morveau published his recommendations in 1782,[10] hoping that his "constant method of denomination" would "help the intelligence and relieve the memory".

The system was refined in Méthode de nomenclature chimique [fr],[11] published in 1787 in collaboration with Lavoisier, Claude Louis Berthollet, and Antoine-François de Fourcroy, and translated into English as Method of Chymical Nomenclature by James St. John in 1788.

[12] Méthode de nomenclature chimique contained handy dictionaries[13] in which older chemical names were listed with their new counterparts[14] and vice versa.

The new system was presented to a wider audience in Lavoisier's 1789 textbook Traité élémentaire de chimie,[17] translated into English as Elements of Chemistry by Robert Kerr in 1790,[18] and it would be of great influence long after his death at the guillotine in 1794.

The project was also endorsed by Swedish chemist Jöns Jakob Berzelius,[19][20] who adapted the ideas for the German-speaking world.

Traité élémentaire de chimie included the first modern list of elements ("simple substances").

[22] For the new "element" caloric, both the new and some of the "old" names (igneous fluid and matter of fire and of heat) were coined by Lavoisier, their discoverer.

An international conference was convened in Geneva in 1892 by the national chemical societies, from which the first widely accepted proposals for standardization developed.

[23] A commission was established in 1913 by the Council of the International Association of Chemical Societies, but its work was interrupted by World War I.

After the war, the task passed to the newly formed International Union of Pure and Applied Chemistry, which first appointed commissions for organic, inorganic, and biochemical nomenclature in 1921 and continues to do so to this day.

The cation retains its elemental name (e.g., iron or zinc), but the suffix of the nonmetal changes to -ide.

For example, the compound LiBr is made of Li+ cations and Br− anions; thus, it is called lithium bromide.

In this system, the metal (instead of a Roman numeral next to it) has a suffix "-ic" or "-ous" added to it to indicate its oxidation state ("-ous" for lower, "-ic" for higher).