Describes a compound that has a macroscopic composition such that its @[email protected] @[email protected] are present in the proportions occurring in nature.
Sources: Blue Book, p. 514 [Terms] [Book] PAC, 1981, 53, 1887. (Nomenclature of inorganic chemistry: II.1 - Isotopically modified compounds) on page 1889 [Terms] [Paper]