Argentous

Argentous is an adjectival form derived from argentum, the Latin name for silver. In chemistry, argentous denotes silver in the +1 oxidation state, and argentous salts are those that contain the silver(I) ion, Ag+. Because silver most commonly exists as Ag+ and forms many stable silver(I) compounds, the term appears chiefly in older or historical literature. The corresponding higher oxidation-state term is argentic, though stable compounds of silver in oxidation states above +1 are rare.

In practice, compounds historically referred to as argentous are now named in the modern IUPAC system as silver(I) compounds. For example, argentous chloride is now called silver(I) chloride (AgCl). If used, argentous oxide would correspond to silver(I) oxide (Ag2O). The term argentous is less widely used in current chemical writing and has largely been superseded by the explicit silver(I) designation. In mineralogy and older chemical texts, argentous and argentic nomenclature may appear, but contemporary references prefer silver(I) or, when applicable, specify the ligands and oxidation state unambiguously.

See also: argentum, silver, argentic, oxidation state.