The four newest elements on the periodic table are nihonium (element 113), moscovium (element 115), tennessine (element 117), and oganesson (element 118). Their addition, formally recognized between 2015 and 2016, completed the seventh row of the table for the first time in its history.1Polyhedron. Row 7 of the periodic table complete: Can we expect more new elements; and if so, when? All four are synthetic, radioactive, and extraordinarily fleeting. They exist only when created inside particle accelerators, sometimes for mere fractions of a second, and they push the boundaries of what “element” even means in practical terms.
The Four Elements That Closed the Seventh Row
Each of the four newest elements was created by slamming lighter atomic nuclei into heavier target nuclei at tremendous speeds, hoping that on rare occasions the two would fuse rather than shatter apart. The discoveries were credited to international teams working at a handful of specialized laboratories in Russia, the United States, Japan, and Germany.2arXiv. The search for superheavy elements: Historical and philosophical perspectives The bulk of the work behind elements 115, 117, and 118 came from a long-running collaboration between Russia’s Joint Institute for Nuclear Research (JINR) in Dubna and the United States’ Lawrence Livermore and Oak Ridge National Laboratories. Element 113 was independently confirmed by a team at Japan’s RIKEN laboratory, earning Japan the distinction of being the first Asian country to name a chemical element.
The naming itself tells you something about the geopolitics and pride wrapped up in these discoveries. Nihonium (Nh) comes from “Nihon,” one of the Japanese words for Japan. Moscovium (Mc) honors the Moscow region where Dubna sits. Tennessine (Ts) nods to Tennessee, home to Oak Ridge. And oganesson (Og) is named after the Russian nuclear physicist Yuri Oganessian, one of only two people in history to have an element named after them while still alive.
Oganesson holds the record as the heaviest element ever created, with 118 protons packed into its nucleus. It was first synthesized in 2002 at JINR, and the discovery was formally validated by an international review panel that confirmed the Dubna-Livermore team had met the longstanding criteria for claiming a new element.3Pure and Applied Chemistry. Discovery of the element with atomic number Z = 118 completing the 7th row of the periodic table (IUPAC Technical Report)
How You Make an Element That Doesn’t Exist in Nature
None of these elements occur naturally on Earth. They are forged inside particle accelerators by firing a beam of lighter ions at a target made from a heavy element, typically an actinide like californium, berkelium, or curium. The beam might run for weeks or months, during which trillions upon trillions of projectile ions hit the target. Out of all those collisions, a successful fusion event that produces a new superheavy atom might happen a handful of times, or not at all. Production rates are so low that researchers typically work with one atom at a time.4Modern Nuclear and Radiochemistry. Recent Progress in Atom-at-a-Time Chemistry of Superheavy Elements with State-of-the-Art Techniques
The most successful projectile for making elements 113 through 118 was calcium-48, a rare and expensive isotope of calcium with an unusually high ratio of neutrons to protons. Calcium-48 beams fired at progressively heavier actinide targets produced each of the four newest elements. That approach, sometimes called “hot fusion,” was the workhorse technique behind nearly every superheavy element discovery in the past two decades.
Once a new atom is created, it doesn’t announce itself. These atoms typically survive for milliseconds to seconds before decaying, emitting a chain of alpha particles as they shed protons and neutrons in a rapid cascade down to lighter, better-known elements. Researchers identify the new atom by detecting that decay chain using highly sensitive silicon detectors positioned behind gas-filled separators that filter the fusion products from the overwhelming background of beam particles. Russia’s new Super Heavy Element Factory at JINR, for instance, uses a purpose-built separator called DGFRS-2 coupled to the powerful DC-280 cyclotron to do exactly this work.5Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. DGFRS-2—A gas-filled recoil separator for the Dubna Super Heavy Element Factory
What Do the Newest Elements Actually Look Like
Nobody has ever seen these elements in any conventional sense. You cannot put them in a jar, weigh them on a scale, or observe their color. The amounts produced are measured in individual atoms, and those atoms exist for so briefly that traditional chemistry is impossible. Yet researchers have still managed to probe their chemical behavior using ingenious techniques that work at the single-atom scale.
Gas-phase chromatography experiments, for example, have revealed that nihonium and moscovium both interact more weakly with silicon oxide surfaces than their lighter counterparts in the same columns of the periodic table, thallium and bismuth respectively. At the same time, they are more reactive than their neighbors copernicium and flerovium.6PubMed Central. Manifestation of relativistic effects in the chemical properties of nihonium and moscovium revealed by gas chromatography studies This pattern is driven by relativistic effects, where the electrons closest to a superheavy nucleus travel at a significant fraction of the speed of light, which changes the shapes and energies of their orbitals and, in turn, alters the element’s chemical personality.
Flerovium (element 114, discovered slightly earlier than the newest four but part of the same superheavy research program) illustrates how bizarre these effects can get. It sits in group 14 of the periodic table, below carbon, silicon, and lead, yet experiments show it behaves nothing like lead. It is highly volatile and the least reactive member of its group, with a reactivity toward gold surfaces that falls somewhere between mercury and the noble gas radon.7Frontiers in Chemistry. On the adsorption and reactivity of element 114, flerovium That’s a striking departure from what you’d expect based on its periodic table address.
Oganesson takes this theme to an extreme. Sitting at the bottom of the noble gas column below helium, neon, argon, krypton, xenon, and radon, you might expect it to be an inert gas. Theoretical calculations tell a different story. The relativistic effects in oganesson are so intense that its outer electrons don’t form the neat, localized shells seen in lighter noble gases. Instead, the electron density in its outer region resembles a uniform smear, something closer to an electron gas. This has led researchers to describe oganesson as “neither noble nor a gas,” since it may actually be a solid at room temperature and could have some chemical reactivity.8PubMed Central. Oganesson: A Noble Gas Element That Is Neither Noble Nor a Gas Of course, confirming that experimentally would require producing far more oganesson atoms than anyone has managed so far.
Preparing to Study Moscovium’s Chemistry
The challenge of doing chemistry one atom at a time forces researchers to develop elaborate proxy experiments. Before attempting chemical studies on a superheavy element itself, teams often rehearse with lighter elements from the same group in the periodic table, testing their detection setups and gas-chromatography apparatus under controlled conditions. A recent example involved studying the behavior of a short-lived bismuth isotope (bismuth-211) on silicon oxide surfaces in different carrier gases, as a dry run for eventual experiments on moscovium, which sits directly below bismuth in group 15.9Radiochimica Acta. Single-atom-at-a-time adsorption studies of 211Bi and its precursor 211Pb on SiO2 surfaces These preparatory studies are not glamorous, but they are essential for building confidence that when a handful of moscovium atoms eventually arrive at the detector, the experiment will capture meaningful data.
The Island of Stability
One of the driving motivations behind the search for ever-heavier elements is a decades-old theoretical prediction known as the island of stability. Nuclear models have long suggested that beyond the known elements, certain combinations of protons and neutrons should form especially tightly bound, “magic number” configurations that resist decay far longer than their neighbors. These nuclei would sit on a metaphorical island surrounded by a sea of ultra-short-lived isotopes.10Nature. Nuclear isomers in superheavy elements as stepping stones towards the island of stability
The exact location of this island remains disputed. Different theoretical models place the center at different proton and neutron counts, with proton number 114 frequently cited, though some models push the prediction higher. That uncertainty is itself important: the superheavy elements discovered so far are providing real experimental benchmarks that help physicists discriminate between competing nuclear models. The existence of flerovium (Z=114) and oganesson (Z=118), along with their measured decay chains, gives theorists calibration points they’ve never had before.
The atoms created so far are neutron-poor compared to the predicted center of the island. The calcium-48 beam technique tends to produce isotopes that are somewhat shy of the ideal neutron count, which means the nuclei created decay quickly even if their proton numbers are in the right range. Getting closer to the island’s heart would likely require producing more neutron-rich isotopes, which in turn demands different beam-target combinations or entirely new synthesis approaches.
The Hunt for Elements 119 and 120
With the seventh row complete, the obvious next question is whether an eighth row can be started. Several laboratories are actively searching for elements 119 and 120, which would be the first elements in a new period of the table. The challenge has proven fierce. An experiment at the GSI laboratory in Darmstadt, Germany, used a titanium-50 beam on berkelium-249 and californium-249 targets over four months of continuous irradiation and detected neither element. The sensitivity limits reached were extraordinarily low, on the order of tens to hundreds of femtobarns.11Physical Review C. Search for elements 119 and 120 To put that in perspective, a femtobarn represents about one event per ten trillion trillion collisions. Not finding anything at those sensitivities doesn’t rule out the elements’ existence; it just means the production probability is extremely small and more beam time, better targets, or new techniques are needed.
The shift from calcium-48 beams to heavier projectiles like titanium-50 or chromium-54 is itself a major complication. Calcium-48 worked remarkably well for a specific window of target nuclei, but to push beyond element 118, heavier projectiles are needed because the available actinide targets have been exhausted in the calcium-48 approach. Heavier projectile-target combinations face higher repulsive barriers between the two colliding nuclei, which makes fusion less likely. Theoretical work is ongoing to predict which beam-target combinations give the best odds, with recent models attempting to extrapolate from the successful calcium-48 data to estimate cross sections for chromium-54 reactions.12arXiv. Synthesis of the superheavy elements beyond Og: extrapolating from 48Ca to 54Cr
Russia’s Super Heavy Element Factory, which began operations in 2020 with beam intensities roughly ten times higher than the previous generation of accelerators, is considered one of the most promising facilities for this work. RIKEN in Japan and GSI in Germany are also in the race. The competition is real but collaborative in an unusual way: target materials like berkelium-249 and californium-249 are available in only tiny quantities from a handful of production reactors worldwide, mostly at Oak Ridge National Laboratory in the U.S. and at facilities in Russia.13Nuclear Physics A. Actinide targets for the synthesis of super-heavy elements Acquiring enough target material can take years of reactor irradiation and chemical processing, making the logistics of element discovery almost as difficult as the physics.
Where the Periodic Table Might End
There is no hard consensus on where the periodic table stops. The practical limit is set by nuclear stability: at some point, the electrostatic repulsion between the huge number of protons overwhelms the nuclear forces holding the atom together, and the nucleus falls apart essentially instantaneously. Most theorists expect that elements up to around 120 or perhaps slightly beyond can be synthesized, but lifetimes may be vanishingly short.
A separate and more fundamental limit comes from atomic physics rather than nuclear physics. As the number of protons grows, the innermost electrons must orbit at ever-higher speeds to remain bound to the increasingly charged nucleus. Beyond a certain nuclear charge, the energy of the lowest electron orbital is predicted to dive into the negative-energy continuum, where the boundary between electrons and their antimatter counterparts (positrons) breaks down. At that point, the atom could spontaneously create electron-positron pairs from the vacuum around it, and the very concept of a stable electron cloud stops making sense.14Nature. The quest for superheavy elements and the limit of the periodic table This doesn’t necessarily mean no nucleus can exist with that many protons, but it does mean the periodic table’s organizing principle, that elements occupy predictable positions based on their electron configurations, may cease to apply.
Some theorists have suggested the periodic table might remain meaningful up to around element 172 or so, while others argue the breakdown begins earlier. The honest answer is that no one knows yet, and the disagreement reflects genuine uncertainty in the physics at these extremes. What is clear is that each new element discovered provides a data point that constrains these models, which is one reason the search continues even when the practical applications of a millisecond-lived atom are essentially zero.
Why Superheavy Elements Matter Beyond the Discovery Itself
A reasonable question is: who cares? If these atoms vanish in milliseconds and are produced one at a time, what’s the point? The value is less about the elements themselves and more about what they reveal. Nuclear physics models that describe how protons and neutrons arrange themselves inside a nucleus have to work across the entire chart of nuclides, from hydrogen all the way up. Superheavy elements test those models at their absolute limit. When a model correctly predicts the half-life or decay mode of a new superheavy isotope, it gains credibility for the regions in between. When it fails, theorists learn where their assumptions break down.
The chemistry is equally revealing. Relativistic effects on electron behavior are present in all heavy elements, including familiar ones like gold (whose distinctive yellow color comes from relativistic shifts in its electron energy levels) and mercury (which is liquid at room temperature partly for the same reason). But in superheavy elements, these effects are cranked up to an extreme that makes them impossible to ignore. Studying how nihonium or flerovium actually behaves, even one atom at a time, tests whether our theoretical treatment of relativity in chemistry is correct or whether surprises still lurk at the bottom of the periodic table.6PubMed Central. Manifestation of relativistic effects in the chemical properties of nihonium and moscovium revealed by gas chromatography studies
There is also a pure-exploration dimension. Humans have filled in row seven of the periodic table within roughly a century and a half of Mendeleev’s original framework. Whether row eight can be opened, and whether the table’s familiar patterns survive there, is one of the genuinely open questions in fundamental science. The facilities and techniques being developed for this search also find use in other areas: medical isotope production, nuclear waste studies, and improving our understanding of the nuclear reactions that forge heavy elements inside merging neutron stars. The quest for element 119 might seem esoteric, but the infrastructure and knowledge it builds ripple outward into research programs with far more immediate consequences.