isotopically unmodified

https://doi.org/10.1351/goldbook.I03339
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]