Web edition: September 27, 2012
Bombarding a bismuth target with a blisteringly fast stream of zinc ions has yielded strong evidence for element 113, a Japanese team reports online September 27 in the Journal of the Physical Society of Japan. The report is the second claim on element 113 by the Japanese team and will eventually be evaluated along with competing claims by a Russian-U.S. team.
Researchers first caught a glimpse of the element in 2003 (SN: 2/07/2004, p. 84), when a Russian-U.S. team witnessed 113 in the aftermath of collisions that produced element 115. As the short-lived element 115 disintegrated, it cast off the two-proton/two-neutron combination known as an alpha particle. The loss of two protons bumped its atomic number down to 113. The team, from the Joint Institute for Nuclear Research in Dubna, Russia, and Lawrence Livermore National Laboratory in California also reported creating 113 in 2007 by bombarding neptunium with calcium.
Now researchers at the RIKEN Linear Accelerator Facility in Japan report creating 113 and cleanly document its disintegration. The team hopes that establishing this decay chain will give it the prestigious naming rights to the element, but the Russian-U.S. team also reported a decay chain in the 2007 results. Until naming rights are determined by the International Union of Pure and Applied Chemistry, which could take years, the element will continue to be known as ununtrium, the IUPAC stand-in name meaning one-one-three.
K. Morita et al. New result in the production and decay of an isotope, 278113, of the 113th element. Journal of the Physical Society of Japan. Vol. 81, October 2012, in press. doi:10.1143/JPSJ.81.103201
P. Weiss. Two new elements made: atom smashups yield 113 and 115. Science News. Vol. 165, Feb. 7, 2004, p. 85.