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Superheavy elements

The superheavy elements, rutherfordium to oganesson, do not occur in nature. Laboratories make them one atom at a time by nuclear fusion1. A joint working party of IUPAC and IUPAP checks each claim before the element gets a name2.

Last updated 14 October 2026.

Which elements they are

This page covers 15 elements, from rutherfordium (element 104) to oganesson (element 118). Physicists now often use the name “superheavy elements” for all elements from rutherfordium upward3. Rutherfordium is the first element after the actinide series3.

Physicists had expected these nuclei to break apart by spontaneous fission. Most known nuclei of these elements decay by giving off alpha particles instead3. Some measured half-lives reach several tens of seconds, even for copernicium-285, one of the heaviest nuclei observed3.

From the 1960s, physicists expected an “island of stability”. This is a group of longer-lived nuclei near a nucleus with closed shells of protons and neutrons3. Some early calculations gave half-lives of millions of years there3. In 2020 Hofmann and his co-authors wrote that the island is less distinct in the measured data than physicists had expected3.

None of these elements has a use outside research. In 2024 Jacklyn Gates of Berkeley Lab said that the known superheavy elements do not live long enough for practical uses4. So there is no mine, no market and no trade.

How they are made

Every element from rutherfordium upward came from a heavy-ion fusion reaction3. An accelerator fires a beam of ions of a lighter element at a thin target of a heavier element. Sometimes two nuclei fuse into one5.

Physicists use two kinds of reaction:

  • Cold fusion. Beams hit targets of lead-208 or bismuth-209. The new nucleus has little excess energy. Most isotopes from bohrium to nihonium came from these reactions3.
  • Hot fusion. Beams of calcium-48 hit targets of radioactive actinides: plutonium, americium, curium, berkelium and californium3. Laboratories used it from the end of the 1990s3. Elements 114 to 118 came from these reactions5.

Fusion is very rare. Early experiments made hundreds of atoms of a new element. Experiments now make one atom or a few3. In 2024 Berkeley Lab made two atoms of element 116 in 22 days of beam time4.

Beams and targets

In 2024 the laboratories in Japan, Russia, China, Germany and the United States could fire more than 6 trillion ions per second at a target6. At RIKEN in Japan, the target sits on a wheel that turns about 2,000 times per minute, so the beam does not burn it. The target still reaches 500 to 1,000 °C6.

The targets come from research reactors. Oak Ridge National Laboratory makes californium targets every other year5. In 2024 Yuri Oganessian of JINR told Science that Russian research reactors can now make the targets too5.

Elements heavier than californium cannot be made in amounts large enough for a target5. Einsteinium-254, for example, can be made only in amounts of a few tens of micrograms3. In 2020 a joint group of IUPAC and IUPAP looked at elements 119 and 120. The group judged lighter actinide targets with beams heavier than calcium-48 to be the most reasonable path3. Beams of this kind are titanium-50, vanadium-51 and chromium-546.

How the atoms are found

A separator with magnets takes the new atoms out of the beam in about a microsecond (a millionth of a second)3. All new elements from 107 to 118 were found this way3. Examples are the Berkeley Gas-filled Separator in the United States and GARIS-III at RIKEN47.

The atom then stops in a silicon detector. The detector records the arrival of the atom and then each alpha particle or fission in its decay chain3. The physicists link the decays of the new nucleus to the known decays of its descendants3.

The hot fusion elements were harder to prove. Their decay chains did not reach any known nucleus3. In 2015 Paul Karol, chair of the working party, named this as a particular difficulty2.

Who makes them

Four laboratories in four countries discovered the 15 elements:

  • Lawrence Berkeley National Laboratory (LBNL), United States: rutherfordium to seaborgium. LBNL includes them in its list of 16 elements that its researchers are credited with4. For elements 104 and 105, the IUPAC and IUPAP Transfermium Working Group gave the credit to Berkeley and Dubna together in 19938.
  • GSI Helmholtz Centre for Heavy Ion Research, Darmstadt, Germany: bohrium to copernicium, from 19819.
  • RIKEN, Japan: nihonium2.
  • The Joint Institute for Nuclear Research (JINR), Dubna, Russia: flerovium to oganesson, with targets from Oak Ridge National Laboratory5. Lawrence Livermore National Laboratory was a partner2.

The US partnership with JINR ended. In 2017 the US Department of State refused to renew Livermore’s agreement with JINR6. Chemistry World reported in 2023 that the partnership broke down after the Russian invasion of Ukraine1.

The search for elements 119 and 120

Laboratories in four countries have started or planned searches for the next elements:

  • RIKEN, Japan, started to search for element 119 in 2018. It used vanadium ions and a curium target5. Its collaboration includes researchers from six countries7. In May 2026 the RIKEN team reported that it had stopped the campaign for a time7.
  • JINR began a search for element 119 in 2026, with berkelium-249 and titanium-5010. JINR planned the experiment to run for several months in 202610.
  • LBNL plans to search for element 120 with titanium-50 and californium-249. In 2024 it said that the search could take several years4.
  • The Institute of Modern Physics in Lanzhou, China, runs a new facility for superheavy elements, CAFE2. In 2025 it said that its tests prepare for the synthesis of new elements11.

GSI searched for element 120 in 2011 and for element 119 in 2012, and found no atoms56. Science reported in 2024 that GSI had stopped these searches5.

How a discovery is checked

IUPAC and IUPAP, the international unions of chemistry and physics, decide who discovered a new element. In 1991 their Transfermium Working Group set the criteria3. A discovery must show, beyond reasonable doubt, a nucleus with a new atomic number. The nucleus must exist for at least 10⁻¹⁴ seconds3. This is about the time that a nucleus needs to collect its electrons3.

For each new claim, the presidents of the two unions appoint a Joint Working Party of six members3. The members must not come from an institution that makes or disputes a claim3. When two claims are both convincing, the earlier date of submission for publication wins3.

The criteria came from disputes. In 1991, some of the elements up to 109 had no name, because the priority of discovery was not clear3. The working group met at the three laboratories most concerned: Berkeley, Dubna and GSI. The group and the three laboratories did not reach agreement3. IUPAC published final names for these elements in 19973.

In 1999 a Berkeley team reported three atoms of element 118 from krypton and lead12. Other groups, and the Berkeley team itself, could not repeat the result13. LBNL withdrew the claim in July 200113. A laboratory investigation concluded that one experimenter had fabricated the evidence13. The press named him as Victor Ninov, who denied the accusations13.

How they are named

Only the discoverers may propose a name and a symbol14. A name can come from a mythological concept, a mineral, a place or country, a property or a scientist2. In its 1997 recommendations, IUPAC changed its 1994 rule that an element must not be named after a living person3.

The ending follows the column of the periodic table: “-ium” for groups 1 to 16, “-ine” for group 17 and “-on” for group 183. A name stays even if a later review gives the credit to another laboratory3.

The proposed names go to public review for five months. The IUPAC Council then makes the final decision2. For elements 113, 115, 117 and 118, IUPAC announced the verified discoveries in December 20152. It approved the names on 28 November 201614.

What it costs

We found no published cost for one atom. We found costs only for buildings and machines. JINR invested 60 million dollars in its Superheavy Element Factory in Dubna6. Its DC-280 cyclotron is designed for a calcium-48 beam ten times stronger than earlier machines15.

Funding also limits the searches. C&EN reported that GSI could not continue its search for element 119. Its resources went to the construction of FAIR, a new accelerator facility that costs 3.3 billion euros6.

The searches need long runs of beam time. Science reported in 2024 that, according to theory, one atom of element 120 could take close to a year of beam time5. In 2024 the US Department of Energy had not yet approved or funded the upgrades for the search5. Sharon Stephenson of the department said: “I cannot say there is funding sitting on a shelf for this effort”5. She added that the department knew of the plans and that its planning supported them5.

Sources

  1. 1

    Kit Chapman, Chemistry World (Royal Society of Chemistry), 2023. Berkeley Lab to lead US hunt for element 120 after breakdown of collaboration with Russia , 10 October 2023, first paragraphs (the rest is for subscribers).

    The superheavy elements do not occur in nature, and the US-Russian partnership that made the five heaviest ended.

    • The superheavy elements are too unstable to be found in nature and are made, one atom at a time, through nuclear fusion
    • The move follows the breakdown of the US–Russian partnership , which had previously discovered the five heaviest elements, following the Russian invasion of Ukraine
  2. 2

    International Union of Pure and Applied Chemistry (IUPAC), 2015. Discovery and Assignment of Elements with Atomic Numbers 113, 115, 117 and 118 , Press release of 30 December 2015.

    The Joint Working Party's verdict on elements 113, 115, 117 and 118, the laboratories credited, and the steps from discovery to a name.

    • The decisions are detailed in two reports by the Joint Working Party (JWP), which includes experts drawn from IUPAC and IUPAP
    • A particular difficulty in establishing these new elements is that they decay into hitherto unknown isotopes of slightly lighter elements that also need to be unequivocally identified
    • The RIKEN collaboration team in Japan have fulfilled the criteria for element Z =113
    • The collaboration between the Joint Institute for Nuclear Research in Dubna, Russia and Lawrence Livermore National Laboratory, California, USA have fulfilled the criteria for element Z =118
    • New elements can be named after a mythological concept, a mineral, a place or country, a property or a scientist
    • the names and two-letter symbols will be presented for public review for five months, before the highest body of IUPAC, the Council, will make a final decision
    • IUPAC announces the verification of the discoveries of four new chemical elements
  3. 3

    Sigurd Hofmann, Sergey N. Dmitriev, Claes Fahlander, Jacklyn M. Gates, James B. Roberto and Hideyuki Sakai; Pure and Applied Chemistry 92(9), 2020. On the discovery of new elements (IUPAC/IUPAP Report) , Sections 1, 2.1, 2.2, 3, 5.1, 6, 6.1, 6.2, 6.6; Attachment 2.

    The meaning of 'superheavy element', cold and hot fusion, separators and detectors, the 1991 discovery criteria, the work of the Joint Working Parties, and the naming rules.

    • it is now often used for all elements from rutherfordium, element 104, upwards
    • rutherfordium is the first element after closure of the actinide series
    • most of these nuclei decay by α-emission and not by spontaneous fission (SF), as expected earlier
    • Some of the measured half-lives extended up to values of several tens of seconds even for the heaviest observed nuclei
    • the doubly magic nucleus having closed shells for protons of
    • the SHN in the vicinity of the double magic nucleus would form an island of stability in a sea of unstable nuclei
    • some calculations obtained half-lives of millions of years for nuclei on the island of spherical SHN
    • The presently existing data on nuclei of elements up to oganesson reveal that the island character of spherical SHN is less pronounced than expected earlier
    • All superheavy elements with proton number
    • were solely produced in heavy ion fusion reactions
    • Most isotopes in the region of the deformed nuclei from bohrium
    • were produced in heavy ion fusion reactions using 208Pb and 209Bi as targets. Due to the exceptional low excitation energy of the compound nucleus these reactions are known as ‘cold fusion’ reactions
    • the new elements from 114 to 118 were produced with targets of 242Pu, 244Pu, 243Am, 245Cm, 248Cm, 249Bk, and 249Cf
    • At the end of the 1990s, similar separation and detection systems were used for study of ‘hot fusion’ reactions using beams of 48Ca and targets of radioactive isotopes of actinide elements
    • When in the past hundreds of atoms could be produced
    • the investigations are dealing now with single or only few atoms produced with cross-sections of picobarns and even below
    • Maximum amounts of only a few tens of micrograms or nanograms, respectively, can be produced
    • reactions using isotopes of lighter actinide targets combined with beams heavier than 48Ca
    • represent the most reasonable path forward
    • The main advantage is the fast separation time of approximately 1 μs
    • All new elements from 107 to 118 were produced using this method
    • the nuclei were identified by decay chains starting with a signal from the implantation of an evaporation residue into a Si detector and subsequent signals from α-decays and/or SF
    • establishing a unique relation between the radioactive decays of those nuclei to known properties of one or more known descendants
    • the new superheavy nuclei, SHN, were located in an area of the chart of nuclei, which, via decay chains, was not connected to any known nucleus
    • Criteria and rules related to assigning priority of discovery of a new element were set up by the Transfermium Working Group, TWG, in 1991
    • the experimental demonstration, beyond reasonable doubt, of the existence of a nuclide with an atomic number
    • existing for at least 10−14 s
    • This lifetime is chosen as a reasonable estimate of the time it takes for a nucleus to acquire its outer electrons
    • a Joint IUPAC-IUPAP Working Party of six members
    • The members must not come from a claimant institution, or from an institution whose earlier claims are questioned, or from an institution questioning those claims
    • The only safely retraceable earliest date and time which can be associated with a discovery is the date of submission of the recorded research work for publication
    • not all of them could be named because in some cases priority of discovery could not be clearly established
    • three laboratories of chief concern at LBNL in Berkeley, JINR in Dubna, and GSI in Darmstadt
    • A common agreement between TWG and the three laboratories was not achieved
    • A final IUPAC Recommendation for the names and symbols of the transfermium elements with atomic number 101 to 109 was published in 1997
    • The 1994 decision that an element should not be named after a living person was changed
    • This would be in general ‘-ium’ for elements belonging to groups 1 to 16, ‘-ine’ for elements of group 17 and ‘-on’ for elements of group 18
    • if and when the priority of discovery of an already named element is successfully challenged, then this element will not be renamed
  4. 4

    Lawrence Berkeley National Laboratory, 2024. A New Way to Make Element 116 Opens the Door to Heavier Atoms , 23 July 2024.

    Two atoms of element 116 from a titanium-50 beam in 22 days, the separator and detector at Berkeley, and the plan for element 120.

    • The superheavy elements we know so far don’t live long enough to be useful for practical purposes
    • The team made two atoms of element 116, livermorium, during 22 days of operations
    • separated from the rest of the particle debris by magnets in the Berkeley Gas-filled Separator (BGS)
    • Berkeley Lab researchers are credited in the discovery of 16 elements
    • 104 – Rutherfordium 105 – Dubnium 106 – Seaborgium
    • Once started, it could take several years to see just a few atoms of element 120, if it appears at all
  5. 5

    Robert F. Service, Science, 2024. U.S. back in race to forge unknown, superheavy elements , 23 July 2024; table 'Superheavy hunters'. Read with Firecrawl; the site refuses scripts..

    Which laboratories discovered which elements, the searches for elements 119 and 120, beam time, and funding at Berkeley.

    • Researchers fire beams of ions of a lighter element into a thin target of a heavier element and hope the two nuclei fuse
    • The most recent superheavies, 114 through 118, were discovered using a beam of calcium-48
    • which it does every other year at one of its research reactors
    • Russian research reactors can now produce the needed targets
    • elements heavier than californium cannot be made in large enough quantities for viable targets
    • With the help of ORNL, which provided the radioactive targets, JINR discovered the last five superheavies
    • In 2018, nuclear scientists at RIKEN, Japan’s national R&D agency, launched an effort to synthesize element 119 by firing vanadium ions into a curium target
    • a 6-week run in 2011 produced no signal for it
    • GSI has since suspended the efforts
    • it could take close to a year of beam time to see a single atom of 120
    • But they must be approved and funded by the Department of Energy (DOE)
    • I cannot say there is funding sitting on a shelf for this effort
    • However, we are very aware of their plans and our planning is supportive of their efforts
  6. 6

    Felicity Nelson, ACS Central Science 10(9), 1669 (C&EN), 2024. How Japan Took the Lead in the Race to Discover Element 119 , 15 August 2024.

    Beam intensities, the rotating target wheel, the cost of the Dubna Superheavy Element Factory and of FAIR, and the end of US cooperation with JINR.

    • The research teams in Japan, Russia, China, Germany, and the US have been boosting the intensity of their ion beams and can now fire more than 6 trillion atoms per second at a target
    • This wheel rotates about 2,000 times per minute, which prevents the beam from incinerating it. Even at these high speeds, the target reaches temperatures of 500–1,000 °C
    • Americium-243 plus a chromium-54 beam Curium-248 plus a vanadium-51 beam Berkelium-249 plus a titanium-50 beam
    • That year, LLNL’s request to renew a longstanding memorandum of understanding with the Russian institution was denied by the US Department of State
    • GSI ran a 4-month experiment using berkelium-249 plus titanium-50 in 2012, but they did not find any atoms of element 119
    • invested $60 million into a new facility in Dubna, Russia, called the Superheavy Element Factory
    • The facility could not continue this research: its resources were put toward constructing the €3.3 billion (about $3.6 billion) Facility for Antiproton and Ion Research
  7. 7

    Kouji Morimoto for the nSHE collaboration, RIKEN Nishina Center, 2026. Search for element 119 in the 248Cm(51V,xn) reaction at RIKEN , Abstract for the TASCA 26 workshop, GSI Darmstadt, 19-21 May 2026.

    The RIKEN collaboration's countries and the pause of its search for element 119.

    • A new gas-filled recoil ion separator, GARIS-III, was also constructed and optimized for hot fusion reactions
    • bringing together researchers from Japan, the USA, France, Poland, Australia, and China
    • we have temporarily concluded this experimental campaign and are now formulating the next strategy
  8. 8

    IUPAC/IUPAP Transfermium Working Group (R. C. Barber, N. N. Greenwood, A. Z. Hrynkiewicz, Y. P. Jeannin, M. Lefort, M. Sakai, I. Ulehla, A. H. Wapstra and D. H. Wilkinson); Pure and Applied Chemistry 65(8), 1757-1814, 1993. Discovery of the transfermium elements , Part III, 104; 06 and 105; 07 (TWG conclusions), pp. 1781 and 1785-1786, and the summary of conclusions.

    The working group's conclusion that Berkeley and Dubna share the credit for elements 104 and 105.

    • each show that element 104 had been produced. Credit should be shared
    • Credit for the discovery should be shared
  9. 9

    GSI Helmholtzzentrum für Schwerionenforschung, 2026. History of GSI: milestones .

    GSI discovered six elements, bohrium to copernicium, from 1981.

    • Discovery of six new chemical elements and their official recognization by IUPAC in the Periodic Table of the Elements: Bohrium, Hassium, Meitnerium, Darmstadtium, Roentgenium, Copernicium
  10. 10

    JINR newspaper (Joint Institute for Nuclear Research, Dubna), number 28, 2026. Start of a big experiment, development of projects, modernization of facilities , 2 July 2026; report of Vladimir Utenkov at the Programme Advisory Committee for Nuclear Physics, 18-19 June 2026.

    The start of the search for element 119 at Dubna in 2026.

    • Experiments on the synthesis of a new element with atomic number 119 in the reaction of the complete fusion of berkelium-249 and titanium-50 nuclei have begun at FLNR
    • The duration of the experiment should be several months in 2026
  11. 11

    Institute of Modern Physics, Chinese Academy of Sciences, 2025. Scientists Discover New, Extremely Neutron-Deficient Isotope Protactinium-210 , 6 June 2025.

    The China Accelerator Facility for Superheavy Elements (CAFE2) in Lanzhou and its aim to make new elements.

    • laying the foundation for experiments on synthesizing new elements
  12. 12

    Physics World (IOP Publishing), 2001. Element 118 disappears two years after it was discovered , 2 August 2001, with a later note on the 2002 retraction.

    The 1999 Berkeley claim for element 118 and its withdrawal.

    • claimed to have detected three atoms of element 118 in collisions between high-energy krypton ions and a lead target
  13. 13

    Bertram M. Schwarzschild, Physics Today (American Institute of Physics), 2002. Lawrence Berkeley Lab Concludes that Evidence of Element 118 Was a Fabrication , September 2002.

    The laboratory's finding of fabricated data, the retraction, and the accused physicist's denial.

    • after various experimental groups around the world, including the Berkeley team itself, were unable to reproduce the 1999 result
    • LBNL had, in fact, already retracted the element-118 discovery claim in July 2001
    • had, in fact, been surreptitiously fabricated by one of the experimenters
    • identified him as Victor Ninov
    • emphatically denies the accusations
  14. 14

    International Union of Pure and Applied Chemistry, 2016. IUPAC Announces the Names of the Elements 113, 115, 117, and 118 , Press release of 30 November 2016.

    The approval of four names after five months of public review, and the rule that only the discoverers propose names.

    • only the discoverers have the right to propose names and symbols
    • On 28 November 2016, the International Union of Pure and Applied Chemistry (IUPAC) approved the name and symbols for four elements
  15. 15

    Joint Institute for Nuclear Research (JINR), Dubna, 2020. First experiment launched at the Superheavy Element Factory , 25 December 2020.

    The first experiment at the Superheavy Element Factory and the design beam intensity of the DC-280 cyclotron.

    • The designed intensity of accelerated heavy-ion calcium-48 beams produced at the DC-280 accelerator will reach 60 trillion ions per second, which is 10 times higher than intensities provided by its predecessors