Overview

Tennessine was first created in 2010 at the Joint Institute for Nuclear Research in Dubna, Russia, in collaboration with American laboratories, by fusing berkelium and calcium nuclei; the berkelium target was supplied by the Oak Ridge National Laboratory in Tennessee. It was named after the state of Tennessee. Tennessine is an intensely radioactive synthetic element, known only from a few atoms, and it is classed with the halogens. Its isotopes last only milliseconds and it has no studied chemistry; whether so heavy an atom truly behaves as a halogen is a question theory cannot yet fully answer, and its synthesis depended on a berkelium target that could be made in only one reactor in the world.

Producing the berkelium-249 target for tennessine's discovery was itself a race against the clock: the isotope has a half-life of only about 330 days, so after roughly 250 days of continuous irradiation at Oak Ridge's High Flux Isotope Reactor yielded just 22 milligrams of usable material, the sample had to be rapidly purified and shipped to Dubna, Russia, and used in the fusion experiment before too much of the hard-won target decayed away, a genuine logistical drama layered on top of the underlying nuclear physics.