Uun

Uun is a three-letter string that appears in various, unrelated contexts and does not represent a single, standard term. It is sometimes encountered as an acronym in different organizations or projects, and in some historical texts it has appeared in connection with chemical nomenclature.

In chemistry, Uun was the symbol used for unununilium, the temporary IUPAC name for the element with atomic number 110. The IUPAC systematic element-naming scheme uses Latinized number prefixes to form temporary names for undiscovered or unconfirmed elements; for 110 the form was un-un-u-ium, often rendered as unununilium with the symbol Uun. Once the element was synthesized and its properties confirmed, it received the permanent name darmstadtium (Ds). The symbol Uun is now obsolete in common scientific use, having been replaced by Ds.

Beyond chemistry, uun may occur as an acronym or code in various contexts, but there is no universal or standardized meaning attached to it. Its interpretation depends entirely on the specific organization, project, or dataset in which it appears.

See also

Unununium and darmstadtium, for historical naming of element 110

Unun- prefixes in IUPAC temporary naming conventions