- Tennessine (Ts) is a synthetic, radioactive element with atomic number 117, belonging to Group 17 of the periodic table, directly beneath astatine.
- It is classified as a halogen, although its properties are expected to differ significantly from lighter halogens due to strong relativistic effects and its position as a superheavy element.
- Its predicted electron configuration is [Rn] 5f¹⁴ 6d¹⁰ 7s² 7p⁵, similar to chlorine, bromine, iodine, and astatine. However, unlike lighter halogens that commonly exhibit a −1 oxidation state, tennessine is expected to favor +1 and +3 states, reflecting its shift toward metallic behavior. The atom contains one hundred and seventeen protons, about one hundred and seventy-four to one hundred and seventy-nine neutrons depending on the isotope, and one hundred and seventeen electrons arranged in seven shells.
- The most stable isotope synthesized so far is tennessine-294 (²⁹⁴Ts), with a half-life of about 20 milliseconds, though some isotopes may live slightly longer.
- Tennessine was first synthesized on April 5, 2010, at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, through an international collaboration involving Russian scientists at JINR, American researchers at Oak Ridge National Laboratory (ORNL), Vanderbilt University, and Lawrence Livermore National Laboratory (LLNL). The discovery was achieved by bombarding a berkelium-249 (²⁴⁹Bk) target with calcium-48 (⁴⁸Ca) ions, producing a few atoms of tennessine-293 (²⁹³Ts) and tennessine-294 (²⁹⁴Ts). These atoms were identified through their decay chains, which included known isotopes of lighter elements.
- The element was named tennessine in honor of the U.S. state of Tennessee, recognizing the contributions of several research institutions in the state, particularly Oak Ridge National Laboratory, Vanderbilt University, and the University of Tennessee. The name and symbol Ts were officially approved by IUPAC in 2016.
- Tennessine has no practical uses outside of basic scientific research. It is produced only in atom-scale quantities and decays almost instantly, limiting its study to nuclear and theoretical chemistry. Its importance lies in expanding knowledge of the periodic table, superheavy elements, and the potential “island of stability.”
- Chemically, tennessine is predicted to share some features with halogens but behave less like a typical nonmetal. While lighter halogens form strong anions such as chloride (Cl⁻) or iodide (I⁻), tennessine is unlikely to form a stable Ts⁻ ion. Instead, it is expected to favor positive oxidation states (+1, +3), and its bonds may show more metallic character. Hypothetical compounds include tennessine(I) fluoride (TsF) and tennessine(III) chloride (TsCl₃). Its reactivity is also predicted to be lower than astatine’s, possibly approaching the border between halogens and noble gases.
- Biologically, tennessine has no role and would be highly radiotoxic if ever encountered in measurable amounts. Its very short half-lives, however, make any biological interactions impossible.
- Environmentally, tennessine does not exist in nature. It can only be produced artificially in particle accelerators and quickly decays into lighter elements, leaving no environmental presence.
