113Nh

Nihonium

Unknown propertiesunknownblock p

The first element ever discovered in Asia, made at RIKEN in Japan after 553 days of continuous beam time produced just three atoms.

Atomic number113
Mass number (longest-lived isotope)286 g/mol
This element has no stable isotope, so it has no standard atomic weight. The figure above is the mass number of its longest-lived isotope — a convention, not a measurement of a natural mixture.
Group · period13 · 7
Electron configuration[Rn] 5f¹⁴ 6d¹⁰ 7s² 7p¹

About Nihonium

Kosuke Morita's team at RIKEN fired zinc-70 at bismuth-209 for nine years, accumulating 553 days of actual beam time to detect three atoms of element 113 — in 2004, 2005 and finally 2012. The 2012 event decayed through a chain ending in known nuclides, which is what clinched the claim over a competing Dubna-Livermore result. The name comes from Nihon, one of the two Japanese readings for Japan, and it is the first element named in Asia. Nothing is known experimentally about its chemistry; under thallium it might behave as a soft heavy metal, but relativistic stabilisation of the 7s pair could make the +1 state overwhelmingly dominant, so no category is asserted here.