Nihonium (Ununtrium)

Ununtrium (Ununtrium) was a systematic placeholder name formerly used for the chemical element with atomic number 113. Its temporary symbol was Uut. The name was derived from IUPAC (International Union of Pure and Applied Chemistry) nomenclature for newly discovered elements pending confirmation of the original discoverers. The term was constructed from the Latin numerals 1-1-3.

In 2016, after the recognition process was completed, the element was assigned the official name nihonium (Nh). The name comes from the Japanese word 'Nihon', meaning Japan. As a result, 'Ununtrium' is now a historical, unofficial name, though it still appears in older literature.

Basic properties

The element is synthetic—it does not occur naturally and is produced in laboratories by colliding accelerated atoms. It belongs to group 13 of the periodic table, the same group as boron, aluminum, and thallium. It is classified as a poor metal based on its estimated properties, since insufficient material has been available for conventional testing.

The known isotopes are highly unstable, decaying through alpha decay or internal conversion. Consequently, experiments rely on only a few atoms created in each trial.

Discovery and recognition

Two groups claimed to have created atoms of element 113: a Japanese team from the RIKEN institute for scientific research, and a Russian-American collaboration working at the Dubna center. IUPAC and IUPAP subsequently awarded the naming rights to the Japanese team, resulting in the official name nihonium.