Tennessine is a synthetic, superheavy halogen (group 17). It is highly radioactive and has only been produced in minute quantities; most physical and chemical properties remain unknown.
Tennessine (Ts) is a superheavy, synthetic element with atomic number 117. It belongs to Group 17 (the halogens: F, Cl, Br, I, At, Ts) and lies in period 7. Because it does not occur naturally, it is created atom-by-atom in particle accelerators and studied at tracer levels only.
Ts is made via fusion–evaporation reactions using a calcium-48 beam on a berkelium-249 target. The hot compound nucleus loses a few neutrons to reach a specific Ts isotope. Stylized examples:
\(^{249}\mathrm{Bk}(^{48}\mathrm{Ca},\,3n)\,^{294}\mathrm{Ts}\)
\(^{249}\mathrm{Bk}(^{48}\mathrm{Ca},\,4n)\,^{293}\mathrm{Ts}\)
Newly formed Ts atoms recoil out of the target into a separator and implant into position-sensitive detectors. Identification relies on time-correlated decay chains with characteristic energies and lifetimes (mainly \(\alpha\)-decays and occasional spontaneous fission):
\(^{A}_{117}\mathrm{Ts} \;\xrightarrow{\alpha}\; ^{A-4}_{115}\mathrm{Mc} \;\xrightarrow{\alpha}\; ^{A-8}_{113}\mathrm{Nh} \;\to\; \cdots\)
Observed isotopes cluster near \(A\approx 293\text{–}294\). Half-lives are typically in the tens to hundreds of milliseconds (some reaching a few seconds), which is long enough to register decay chains but too short for conventional bulk measurements or wet-chemistry experiments.
Unlike lighter halogens that strongly favor −1, Ts is predicted—because of strong relativistic effects—to stabilize +1 and +3 states more readily, with −1 likely less stable. Higher positive states (e.g., +5) may be accessible in highly oxidizing environments but are expected to be less favored than for chlorine or bromine.
A commonly cited ground state is [Rn] 5f14 6d10 7s2 7p5. Strong spin–orbit splitting divides the 7p subshell (\(7p_{1/2}\) vs. \(7p_{3/2}\)), helping to explain Ts’s reduced tendency to form the classic halide −1 state and an increased likelihood of positive oxidation states.
Only indirect evidence exists. Theory and single-atom surface/gas-phase approaches suggest Ts may be less reactive than lighter halogens and could show quasi-metallic behavior in some contexts. If compounds form, monovalent (Ts(I)) and trivalent (Ts(III)) species are considered more plausible than a stable Ts(−I) in condensed phases.
Experiments produce only a few atoms that decay quickly, preventing the preparation of macroscopic samples. As a result, properties like density, melting point, crystal structure, and color are mostly theoretical predictions based on relativistic quantum calculations and periodic trends.
Yes. Ts is a radiotoxic, superheavy element. Although handled only in atom-scale quantities, all work requires remote manipulation, high-vacuum separators, appropriate shielding, HEPA-filtered ventilation, dosimetry, and compliant radioactive-waste procedures in specialized laboratories.
A representative \(\alpha\)-decay step is:
\(^{294}\mathrm{Ts} \;\xrightarrow{\alpha}\; ^{290}\mathrm{Mc} + \alpha\)
Subsequent daughters typically continue via \(\alpha\) emissions and may terminate in spontaneous fission at some point in the chain.