Isotopes of tennessine


is the most-recently synthesized synthetic element, and much of the data is hypothetical. As for any synthetic element, a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotopes to be synthesized were 293Ts and 294Ts in 2009. The longer-lived isotope is 294Ts with a half-life of 51 ms.

List of isotopes

Isotopes and nuclear properties

Nucleosynthesis

Target-projectile combinations leading to Z=117 compound nuclei

The below table contains various combinations of targets and projectiles that could be used to form compound nuclei with atomic number 117.
TargetProjectileCNAttempt result
208Pb81Br289Ts
209Bi82Se291Ts
238U55Mn293Ts
243Am50Ti293Ts
249Bk48Ca297Ts

Hot fusion

249Bk (48Ca, ''x''n)297−''x''Ts (''x''=3,4)
Between July 2009 and February 2010, the team at the JINR ran a 7-month-long experiment to synthesize tennessine using the reaction above.
The expected cross-section was of the order of 2 pb. The expected evaporation residues, 293Ts and 294Ts, were predicted to decay via relatively long decay chains as far as isotopes of dubnium or lawrencium.


The team published a scientific paper in April 2010 that six atoms of the neighbouring isotopes 294Ts and 293Ts were detected. The heavier isotope decayed by the successive emission of six alpha particles down as far as the new isotope 270Db, which underwent apparent spontaneous fission. On the other hand, the lighter odd-even isotope decayed by the emission of just three alpha particles, as far as 281Rg, which underwent spontaneous fission. The reaction was run at two different excitation energies of 35 MeV and 39 MeV. Initial decay data was published as a preliminary presentation on the JINR website.
A further experiment in May 2010, aimed at studying the chemistry of the granddaughter of tennessine, nihonium, identified a further two atoms of 286Nh from the decay of 294Ts. The original experiment was repeated successfully by the same collaboration in 2012 and by a joint German–American team in May 2014, confirming the discovery.

Chronology of isotope discovery

Theoretical calculations

Evaporation residue cross sections

The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.
DNS = Di-nuclear system; σ = cross section
TargetProjectileCNChannel σmaxModelRef
209Bi82Se291Ts1n 15 fbDNS
209Bi79Se288Ts1n 0.2 pbDNS
232Th59Co291Ts2n 0.1 pbDNS
238U55Mn293Ts2-3n 70 fbDNS
244Pu51V295Ts3n 0.6 pbDNS
248Cm45Sc293Ts4n 2.9 pbDNS
246Cm45Sc291Ts4n 1 pbDNS
249Bk48Ca297Ts3n 2.1 pb ; 3 pbDNS
247Bk48Ca295Ts3n 0.8, 0.9 pbDNS

Decay characteristics

Theoretical calculations in a quantum tunneling model with mass estimates from a macroscopic-microscopic model predict the alpha-decay half-lives of isotopes of tennessine to be around 0.1–40 ms.

External sources