nihonium

nihonium (Nh), artificially produced transuranium element of atomic number 113. In 2004 scientists at the RIKEN Nishina Center for Accelerator-Based Science in Saitama, Japan announced the production of one atom of element 113, which was formed when bismuth-209 was fused with zinc-70. Extremely radioactive, the atom decayed through emission of alpha particles (helium nuclei) to dubnium-262 in about 2.5 seconds. Its chemical properties may be similar to those of thallium. The element has six isotopes with known and confirmed half-lives, the longest-lived of which is nihonium-286 with a half-life of 19.6 seconds; most of these radioactive isotopes were not directly synthesized but occured as decay products. In January 2016 the discovery of element 113 was recognized by the International Union of Pure and Applied Chemistry (IUPAC) and the International Union of Pure and Applied Physics (IUPAP). The discoverers named it nihonium after the Japanese word for Japan. The name nihonium was approved by IUPAC in November 2016.