|Livermorium in the periodic table|
|Atomic number (Z)||116|
|Group||group 16 (chalcogens)|
|Electron configuration||[Rn] 5f14 6d10 7s2 7p4 (predicted)|
|Electrons per shell||2, 8, 18, 32, 32, 18, 6 (predicted)|
|Phase at STP||solid (predicted)|
|Melting point||637–780 K (364–507 °C, 687–944 °F) (extrapolated)|
|Boiling point||1035–1135 K (762–862 °C, 1403–1583 °F) (extrapolated)|
|Density (near r.t.)||12.9 g/cm3 (predicted)|
|Heat of fusion||7.61 kJ/mol (extrapolated)|
|Heat of vaporization||42 kJ/mol (predicted)|
|Oxidation states||(−2), (+2), (+4) (predicted)|
|Atomic radius||empirical: 183 pm (predicted)|
|Covalent radius||162–166 pm (extrapolated)|
|Naming||after Lawrence Livermore National Laboratory, itself named partly after Livermore, California|
|Discovery||Joint Institute for Nuclear Research and Lawrence Livermore National Laboratory (2000)|
|Main isotopes of livermorium|
Livermorium is a synthetic chemical element with the symbol Lv and has an atomic number of 116. It is an extremely radioactive element that has only been created in the laboratory and has not been observed in nature. The element is named after the Lawrence Livermore National Laboratory in the United States, which collaborated with the Joint Institute for Nuclear Research (JINR) in Dubna, Russia to discover livermorium during experiments made between 2000 and 2006. The name of the laboratory refers to the city of Livermore, California where it is located, which in turn was named after the rancher and landowner Robert Livermore. The name was adopted by IUPAC on May 30, 2012. Four isotopes of livermorium are known, with mass numbers between 290 and 293 inclusive; the longest-lived among them is livermorium-293 with a half-life of about 60 milliseconds. A fifth possible isotope with mass number 294 has been reported but not yet confirmed.
In the periodic table, it is a p-block transactinide element. It is a member of the 7th period and is placed in group 16 as the heaviest chalcogen, although it has not been confirmed to behave as the heavier homologue to the chalcogen polonium. Livermorium is calculated to have some similar properties to its lighter homologues (oxygen, sulfur, selenium, tellurium, and polonium), and be a post-transition metal, although it should also show several major differences from them.
|Visualization of unsuccessful nuclear fusion, based on calculations by the Australian National University|
The heaviest[a] atomic nuclei are created in nuclear reactions that combine two other nuclei of unequal size[b] into one; roughly, the more unequal the two nuclei in terms of mass, the greater the possibility that the two react. The material made of the heavier nuclei is made into a target, which is then bombarded by the beam of lighter nuclei. Two nuclei can only fuse into one if they approach each other closely enough; normally, nuclei (all positively charged) repel each other due to electrostatic repulsion. The strong interaction can overcome this repulsion but only within a very short distance from a nucleus; beam nuclei are thus greatly accelerated in order to make such repulsion insignificant compared to the velocity of the beam nucleus. Coming close alone is not enough for two nuclei to fuse: when two nuclei approach each other, they usually remain together for approximately 10−20 seconds and then part ways (not necessarily in the same composition as before the reaction) rather than form a single nucleus. If fusion does occur, the temporary merger—termed a compound nucleus—is an excited state. To lose its excitation energy and reach a more stable state, a compound nucleus either fissions or ejects one or several neutrons,[c] which carry away the energy. This occurs in approximately 10−16 seconds after the initial collision.[d]
The beam passes through the target and reaches the next chamber, the separator; if a new nucleus is produced, it is carried with this beam. In the separator, the newly produced nucleus is separated from other nuclides (that of the original beam and any other reaction products)[e] and transferred to a surface-barrier detector, which stops the nucleus. The exact location of the upcoming impact on the detector is marked; also marked are its energy and the time of the arrival. The transfer takes about 10−6 seconds; in order to be detected, the nucleus must survive this long. The nucleus is recorded again once its decay is registered, and the location, the energy, and the time of the decay are measured.
Stability of a nucleus is provided by the strong interaction. However, its range is very short; as nuclei become larger, its influence on the outermost nucleons (protons and neutrons) weakens. At the same time, the nucleus is torn apart by electrostatic repulsion between protons, as it has unlimited range. Nuclei of the heaviest elements are thus theoretically predicted and have so far been observed to primarily decay via decay modes that are caused by such repulsion: alpha decay and spontaneous fission;[f] these modes are predominant for nuclei of superheavy elements. Alpha decays are registered by the emitted alpha particles, and the decay products are easy to determine before the actual decay; if such a decay or a series of consecutive decays produces a known nucleus, the original product of a reaction can be determined arithmetically.[g] Spontaneous fission, however, produces various nuclei as products, so the original nuclide cannot be determined from its daughters.[h]
The information available to physicists aiming to synthesize one of the heaviest elements is thus the information collected at the detectors: location, energy, and time of arrival of a particle to the detector, and those of its decay. The physicists analyze this data and seek to conclude that it was indeed caused by a new element and could not have been caused by a different nuclide than the one claimed. Often, provided data is insufficient for a conclusion that a new element was definitely created and there is no other explanation for the observed effects; errors in interpreting data have been made.[i]
Unsuccessful synthesis attempts
The first search for element 116, using the reaction between 248Cm and 48Ca, was performed in 1977 by Ken Hulet and his team at the Lawrence Livermore National Laboratory (LLNL). They were unable to detect any atoms of livermorium. Yuri Oganessian and his team at the Flerov Laboratory of Nuclear Reactions (FLNR) in the Joint Institute for Nuclear Research (JINR) subsequently attempted the reaction in 1978 and met failure. In 1985, in a joint experiment between Berkeley and Peter Armbruster's team at GSI, the result was again negative, with a calculated cross section limit of 10–100 pb. Work on reactions with 48Ca, which had proved very useful in the synthesis of nobelium from the natPb+48Ca reaction, nevertheless continued at Dubna, with a superheavy element separator being developed in 1989, a search for target materials and starting of collaborations with LLNL being started in 1990, production of more intense 48Ca beams being started in 1996, and preparations for long-term experiments with 3 orders of magnitude higher sensitivity being performed in the early 1990s. This work led directly to the production of new isotopes of elements 112 to 118 in the reactions of 48Ca with actinide targets and the discovery of the 5 heaviest elements on the periodic table: flerovium, moscovium, livermorium, tennessine, and oganesson.
In 1995, an international team led by Sigurd Hofmann at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany attempted to synthesise element 116 in a radiative capture reaction (in which the compound nucleus de-excites through pure gamma emission without evaporating neutrons) between a lead-208 target and selenium-82 projectiles. No atoms of element 116 were identified.
Unconfirmed discovery claims
In late 1998, Polish physicist Robert Smolańczuk published calculations on the fusion of atomic nuclei towards the synthesis of superheavy atoms, including elements 118 and 116. His calculations suggested that it might be possible to make these two elements by fusing lead with krypton under carefully controlled conditions.
In 1999, researchers at Lawrence Berkeley National Laboratory made use of these predictions and announced the discovery of elements 118 and 116, in a paper published in Physical Review Letters, and very soon after the results were reported in Science. The researchers reported to have performed the reaction
The following year, they published a retraction after researchers at other laboratories were unable to duplicate the results and the Berkeley lab itself was unable to duplicate them as well. In June 2002, the director of the lab announced that the original claim of the discovery of these two elements had been based on data fabricated by principal author Victor Ninov.
Livermorium was first synthesized on July 19, 2000, when scientists at Dubna (JINR) bombarded a curium-248 target with accelerated calcium-48 ions. A single atom was detected, decaying by alpha emission with decay energy 10.54 MeV to an isotope of flerovium. The results were published in December 2000.
* → 293
+ 3 1
The daughter flerovium isotope had properties matching those of a flerovium isotope first synthesized in June 1999, which was originally assigned to 288Fl, implying an assignment of the parent livermorium isotope to 292Lv. Later work in December 2002 indicated that the synthesized flerovium isotope was actually 289Fl, and hence the assignment of the synthesized livermorium atom was correspondingly altered to 293Lv.
Road to confirmation
Two further atoms were reported by the institute during their second experiment during April–May 2001. In the same experiment they also detected a decay chain which corresponded to the first observed decay of flerovium in December 1998, which had been assigned to 289Fl. No flerovium isotope with the same properties as the one found in December 1998 has ever been observed again, even in repeats of the same reaction. Later it was found that 289Fl has different decay properties and that the first observed flerovium atom may have been its nuclear isomer 289mFl. The observation of 289mFl in this series of experiments may indicate the formation of a parent isomer of livermorium, namely 293mLv, or a rare and previously unobserved decay branch of the already-discovered state 293Lv to 289mFl. Neither possibility is certain, and research is required to positively assign this activity. Another possibility suggested is the assignment of the original December 1998 atom to 290Fl, as the low beam energy used in that original experiment makes the 2n channel plausible; its parent could then conceivably be 294Lv, but this assignment would still need confirmation in the 248Cm(48Ca,2n)294Lv reaction.
The team repeated the experiment in April–May 2005 and detected 8 atoms of livermorium. The measured decay data confirmed the assignment of the first-discovered isotope as 293Lv. In this run, the team also observed the isotope 292Lv for the first time. In further experiments from 2004 to 2006, the team replaced the curium-248 target with the lighter curium isotope curium-245. Here evidence was found for the two isotopes 290Lv and 291Lv.
In May 2009, the IUPAC/IUPAP Joint Working Party reported on the discovery of copernicium and acknowledged the discovery of the isotope 283Cn. This implied the de facto discovery of the isotope 291Lv, from the acknowledgment of the data relating to its granddaughter 283Cn, although the livermorium data was not absolutely critical for the demonstration of copernicium's discovery. Also in 2009, confirmation from Berkeley and the Gesellschaft für Schwerionenforschung (GSI) in Germany came for the flerovium isotopes 286 to 289, immediate daughters of the four known livermorium isotopes. In 2011, IUPAC evaluated the Dubna team experiments of 2000–2006. Whereas they found the earliest data (not involving 291Lv and 283Cn) inconclusive, the results of 2004–2006 were accepted as identification of livermorium, and the element was officially recognized as having been discovered.
The synthesis of livermorium has been separately confirmed at the GSI (2012) and RIKEN (2014 and 2016). In the 2012 GSI experiment, one chain tentatively assigned to 293Lv was shown to be inconsistent with previous data; it is believed that this chain may instead originate from an isomeric state, 293mLv. In the 2016 RIKEN experiment, one atom that may be assigned to 294Lv was seemingly detected, alpha decaying to 290Fl and 286Cn, which underwent spontaneous fission; however, the first alpha from the livermorium nuclide produced was missed, and the assignment to 294Lv is still uncertain though plausible.
Using Mendeleev's nomenclature for unnamed and undiscovered elements, livermorium is sometimes called eka-polonium. In 1979 IUPAC recommended that the placeholder systematic element name ununhexium (Uuh) be used until the discovery of the element was confirmed and a name was decided. Although widely used in the chemical community on all levels, from chemistry classrooms to advanced textbooks, the recommendations were mostly ignored among scientists in the field, who called it "element 116", with the symbol of E116, (116), or even simply 116.
According to IUPAC recommendations, the discoverer or discoverers of a new element have the right to suggest a name. The discovery of livermorium was recognized by the Joint Working Party (JWP) of IUPAC on 1 June 2011, along with that of flerovium. According to the vice-director of JINR, the Dubna team originally wanted to name element 116 moscovium, after the Moscow Oblast in which Dubna is located, but it was later decided to use this name for element 115 instead. The name livermorium and the symbol Lv were adopted on May 23, 2012. The name recognises the Lawrence Livermore National Laboratory, within the city of Livermore, California, USA, which collaborated with JINR on the discovery. The city in turn is named after the American rancher Robert Livermore, a naturalized Mexican citizen of English birth. The naming ceremony for flerovium and livermorium was held in Moscow on October 24, 2012.
Other than nuclear properties, no properties of livermorium or its compounds have been measured; this is due to its extremely limited and expensive production and the fact that it decays very quickly. Properties of livermorium remain unknown and only predictions are available.
Nuclear stability and isotopes
Livermorium is expected to be near an island of stability centered on copernicium (element 112) and flerovium (element 114). Due to the expected high fission barriers, any nucleus within this island of stability exclusively decays by alpha decay and perhaps some electron capture and beta decay. While the known isotopes of livermorium do not actually have enough neutrons to be on the island of stability, they can be seen to approach the island, as the heavier isotopes are generally the longer-lived ones.
Superheavy elements are produced by nuclear fusion. These fusion reactions can be divided into "hot" and "cold" fusion,[j] depending on the excitation energy of the compound nucleus produced. In hot fusion reactions, very light, high-energy projectiles are accelerated toward very heavy targets (actinides), giving rise to compound nuclei at high excitation energy (~40–50 MeV) that may either fission or evaporate several (3 to 5) neutrons. In cold fusion reactions (which use heavier projectiles, typically from the fourth period, and lighter targets, usually lead and bismuth), the produced fused nuclei have a relatively low excitation energy (~10–20 MeV), which decreases the probability that these products will undergo fission reactions. As the fused nuclei cool to the ground state, they require emission of only one or two neutrons. Hot fusion reactions tend to produce more neutron-rich products because the actinides have the highest neutron-to-proton ratios of any elements that can presently be made in macroscopic quantities.
Important information could be gained regarding the properties of superheavy nuclei by the synthesis of more livermorium isotopes, specifically those with a few neutrons more or less than the known ones – 286Lv, 287Lv, 288Lv, 289Lv, 294Lv, and 295Lv. This is possible because there are many reasonably long-lived isotopes of curium that can be used to make a target. The light isotopes can be made by fusing curium-243 with calcium-48. They would undergo a chain of alpha decays, ending at transactinide isotopes that are too light to achieve by hot fusion and too heavy to be produced by cold fusion.
The synthesis of the heavy isotopes 294Lv and 295Lv could be accomplished by fusing the heavy curium isotope curium-250 with calcium-48. The cross section of this nuclear reaction would be about 1 picobarn, though it is not yet possible to produce 250Cm in the quantities needed for target manufacture. After a few alpha decays, these livermorium isotopes would reach nuclides at the line of beta stability. Additionally, electron capture may also become an important decay mode in this region, allowing affected nuclei to reach the middle of the island. For example, it is predicted that 295Lv would alpha decay to 291Fl, which would undergo successive electron capture to 291Nh and then 291Cn which is expected to be in the middle of the island of stability and have a half-life of about 1200 years, affording the most likely hope of reaching the middle of the island using current technology. A drawback is that the decay properties of superheavy nuclei this close to the line of beta stability are largely unexplored.
Other possibilities to synthesize nuclei on the island of stability include quasifission (partial fusion followed by fission) of a massive nucleus. Such nuclei tend to fission, expelling doubly magic or nearly doubly magic fragments such as calcium-40, tin-132, lead-208, or bismuth-209. Recently it has been shown that the multi-nucleon transfer reactions in collisions of actinide nuclei (such as uranium and curium) might be used to synthesize the neutron-rich superheavy nuclei located at the island of stability, although formation of the lighter elements nobelium or seaborgium is more favored. One last possibility to synthesize isotopes near the island is to use controlled nuclear explosions to create a neutron flux high enough to bypass the gaps of instability at 258–260Fm and at mass number 275 (atomic numbers 104 to 108), mimicking the r-process in which the actinides were first produced in nature and the gap of instability around radon bypassed. Some such isotopes (especially 291Cn and 293Cn) may even have been synthesized in nature, but would have decayed away far too quickly (with half-lives of only thousands of years) and be produced in far too small quantities (about 10−12 the abundance of lead) to be detectable as primordial nuclides today outside cosmic rays.
Physical and atomic
In the periodic table, livermorium is a member of group 16, the chalcogens. It appears below oxygen, sulfur, selenium, tellurium, and polonium. Every previous chalcogen has six electrons in its valence shell, forming a valence electron configuration of ns2np4. In livermorium's case, the trend should be continued and the valence electron configuration is predicted to be 7s27p4; therefore, livermorium will have some similarities to its lighter congeners. Differences are likely to arise; a large contributing effect is the spin–orbit (SO) interaction—the mutual interaction between the electrons' motion and spin. It is especially strong for the superheavy elements, because their electrons move much faster than in lighter atoms, at velocities comparable to the speed of light. In relation to livermorium atoms, it lowers the 7s and the 7p electron energy levels (stabilizing the corresponding electrons), but two of the 7p electron energy levels are stabilized more than the other four. The stabilization of the 7s electrons is called the inert pair effect, and the effect "tearing" the 7p subshell into the more stabilized and the less stabilized parts is called subshell splitting. Computation chemists see the split as a change of the second (azimuthal) quantum number l from 1 to 1⁄2 and 3⁄2 for the more stabilized and less stabilized parts of the 7p subshell, respectively: the 7p1/2 subshell acts as a second inert pair, though not as inert as the 7s electrons, while the 7p3/2 subshell can easily participate in chemistry.[k] For many theoretical purposes, the valence electron configuration may be represented to reflect the 7p subshell split as 7s2
The inert pair effects in livermorium should be even stronger than for polonium and hence the +2 oxidation state becomes more stable than the +4 state, which would be stabilized only by the most electronegative ligands; this is reflected in the expected ionization energies of livermorium, where there are large gaps between the second and third ionization energies (corresponding to the breaching of the unreactive 7p1/2 shell) and fourth and fifth ionization energies. Indeed, the 7s electrons are expected to be so inert that the +6 state will not be attainable. The melting and boiling points of livermorium are expected to continue the trends down the chalcogens; thus livermorium should melt at a higher temperature than polonium, but boil at a lower temperature. It should also be denser than polonium (α-Lv: 12.9 g/cm3; α-Po: 9.2 g/cm3); like polonium it should also form an α and a β allotrope. The electron of the hydrogen-like livermorium atom (oxidized so that it only has one electron, Lv115+) is expected to move so fast that it has a mass 1.86 times that of a stationary electron, due to relativistic effects. For comparison, the figures for hydrogen-like polonium and tellurium are expected to be 1.26 and 1.080 respectively.
Livermorium is projected to be the fourth member of the 7p series of chemical elements and the heaviest member of group 16 in the periodic table, below polonium. While it is the least theoretically studied of the 7p elements, its chemistry is expected to be quite similar to that of polonium. The group oxidation state of +6 is known for all the chalcogens apart from oxygen which cannot expand its octet and is one of the strongest oxidizing agents among the chemical elements. Oxygen is thus limited to a maximum +2 state, exhibited in the fluoride OF2. The +4 state is known for sulfur, selenium, tellurium, and polonium, undergoing a shift in stability from reducing for sulfur(IV) and selenium(IV) through being the most stable state for tellurium(IV) to being oxidizing in polonium(IV). This suggests a decreasing stability for the higher oxidation states as the group is descended due to the increasing importance of relativistic effects, especially the inert pair effect. The most stable oxidation state of livermorium should thus be +2, with a rather unstable +4 state. The +2 state should be about as easy to form as it is for beryllium and magnesium, and the +4 state should only be achieved with strongly electronegative ligands, such as in livermorium(IV) fluoride (LvF4). The +6 state should not exist at all due to the very strong stabilization of the 7s electrons, making the valence core of livermorium only four electrons. The lighter chalcogens are also known to form a −2 state as oxide, sulfide, selenide, telluride, and polonide; due to the destabilization of livermorium's 7p3/2 subshell, the −2 state should be very unstable for livermorium, whose chemistry should be essentially purely cationic, though the larger subshell and spinor energy splittings of livermorium as compared to polonium should make Lv2− slightly less unstable than expected.
Livermorane (LvH2) would be the heaviest chalcogen hydride and the heaviest homolog of water (the lighter ones being H2S, H2Se, H2Te, and PoH2). Polane (polonium hydride) is a more covalent compound than most metal hydrides because polonium straddles the border between metals and metalloids and has some nonmetallic properties: it is intermediate between a hydrogen halide like hydrogen chloride (HCl) and a metal hydride like stannane (SnH4). Livermorane should continue this trend: it should be a hydride rather than a livermoride, but would still be a covalent molecular compound. Spin-orbit interactions are expected to make the Lv–H bond longer than expected simply from periodic trends alone, and make the H–Lv–H bond angle larger than expected: this is theorized to be because the unoccupied 8s orbitals are relatively low in energy and can hybridize with the valence 7p orbitals of livermorium. This phenomenon, dubbed "supervalent hybridization", is not particularly uncommon in non-relativistic regions in the periodic table; for example, molecular calcium difluoride has 4s and 3d involvement from the calcium atom. The heavier livermorium dihalides are predicted to be linear, but the lighter ones are predicted to be bent.
Unambiguous determination of the chemical characteristics of livermorium has not yet been established. In 2011, experiments were conducted to create nihonium, flerovium, and moscovium isotopes in the reactions between calcium-48 projectiles and targets of americium-243 and plutonium-244. The targets included lead and bismuth impurities and hence some isotopes of bismuth and polonium were generated in nucleon transfer reactions. This, while an unforeseen complication, could give information that would help in the future chemical investigation of the heavier homologs of bismuth and polonium, which are respectively moscovium and livermorium. The produced nuclides bismuth-213 and polonium-212m were transported as the hydrides 213BiH3 and 212mPoH2 at 850 °C through a quartz wool filter unit held with tantalum, showing that these hydrides were surprisingly thermally stable, although their heavier congeners McH3 and LvH2 would be expected to be less thermally stable from simple extrapolation of periodic trends in the p-block. Further calculations on the stability and electronic structure of BiH3, McH3, PoH2, and LvH2 are needed before chemical investigations take place. Moscovium and livermorium are expected to be volatile enough as pure elements for them to be chemically investigated in the near future, a property livermorium would then share with its lighter congener polonium, though the short half-lives of all presently known livermorium isotopes means that the element is still inaccessible to experimental chemistry.
- In nuclear physics, an element is called heavy if its atomic number is high; lead (element 82) is one example of such a heavy element. The term "superheavy elements" typically refers to elements with atomic number greater than 103 (although there are other definitions, such as atomic number greater than 100 or 112; sometimes, the term is presented an equivalent to the term "transactinide", which puts an upper limit before the beginning of the hypothetical superactinide series). Terms "heavy isotopes" (of a given element) and "heavy nuclei" mean what could be understood in the common language—isotopes of high mass (for the given element) and nuclei of high mass, respectively.
- In 2009, a team at JINR led by Oganessian published results of their attempt to create hassium in a symmetric 136Xe + 136Xe reaction. They failed to observe a single atom in such a reaction, putting the upper limit on the cross section, the measure of probability of a nuclear reaction, as 2.5 pb. In comparison, the reaction that resulted in hassium discovery, 208Pb + 58Fe, had a cross section of ~20 pb (more specifically, 19+19
−11 pb), as estimated by the discoverers.
- The greater the excitation energy, the more neutrons are ejected. If the excitation energy is lower than energy binding each neutron to the rest of the nucleus, neutrons are not emitted; instead, the compound nucleus de-excites by emitting a gamma ray.
- The definition by the IUPAC/IUPAP Joint Working Party states that a chemical element can only be recognized as discovered if a nucleus of it has not decayed within 10−14 seconds. This value was chosen as an estimate of how long it takes a nucleus to acquire its outer electrons and thus display its chemical properties. This figure also marks the generally accepted upper limit for lifetime of a compound nucleus.
- This separation is based on that the resulting nuclei move past the target more slowly then the unreacted beam nuclei. The separator contains electric and magnetic fields whose effects on a moving particle cancel out for a specific velocity of a particle. Such separation can also be aided by a time-of-flight measurement and a recoil energy measurement; a combination of the two may allow to estimate the mass of a nucleus.
- Not all decay modes are caused by electrostatic repulsion. For example, beta decay is caused by the weak interaction.
- Since mass of a nucleus is not measured directly but is rather calculated from that of another nucleus, such measurement is called indirect. Direct measurements are also possible, but for the most part they have remained unavailable for heaviest nuclei. The first direct measurement of mass of a superheavy nucleus was reported in 2018 at LBNL. Mass was determined from the location of a nucleus after the transfer (the location helps determine its trajectory, which is linked to the mass-to-charge ratio of the nucleus, since the transfer was done in presence of a magnet).
- Spontaneous fission was discovered by Soviet physicist Georgy Flerov, a leading scientist at JINR, and thus it was a "hobbyhorse" for the facility. In contrast, the LBL scientists believed fission information was not sufficient for a claim of synthesis of an element. They believed spontaneous fission had not been studied enough to use it for identification of a new element, since there was a difficulty of establishing that a compound nucleus had only ejected neutrons and not charged particles like protons or alpha particles. They thus preferred to link new isotopes to the already known ones by successive alpha decays.
- For instance, element 102 was mistakenly identified in 1957 at the Nobel Institute of Physics in Stockholm, Stockholm County, Sweden. There were no earlier definitive claims of creation of this element, and the element was assigned a name by its Swedish, American, and British discoverers, nobelium. It was later shown that the identification was incorrect. The following year, LBNL was unable to reproduce the Swedish results and announced instead their synthesis of the element; that claim was also disproved later. JINR insisted that they were the first to create the element and suggested a name of their own for the new element, joliotium; the Soviet name was also not accepted (JINR later referred to the naming of element 102 as "hasty"). The name "nobelium" remained unchanged on account of its widespread usage.
- Despite the name, "cold fusion" in the context of superheavy element synthesis is a distinct concept from the idea that nuclear fusion can be achieved in room temperature conditions (see cold fusion).
- The quantum number corresponds to the letter in the electron orbital name: 0 to s, 1 to p, 2 to d, etc. See azimuthal quantum number for more information.
- Hoffman, Darleane C.; Lee, Diana M.; Pershina, Valeria (2006). "Transactinides and the future elements". In Morss; Edelstein, Norman M.; Fuger, Jean (eds.). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer Science+Business Media. ISBN 978-1-4020-3555-5.
- Bonchev, Danail; Kamenska, Verginia (1981). "Predicting the Properties of the 113–120 Transactinide Elements". Journal of Physical Chemistry. American Chemical Society. 85 (9): 1177–1186. doi:10.1021/j150609a021.
- Fricke, Burkhard (1975). "Superheavy elements: a prediction of their chemical and physical properties". Recent Impact of Physics on Inorganic Chemistry. 21: 89–144. doi:10.1007/BFb0116498. Retrieved 4 October 2013.
- Thayer, John S. (2010). "Relativistic Effects and the Chemistry of the Heavier Main Group Elements". Relativistic Methods for Chemists. Challenges and Advances in Computational Chemistry and Physics. 10: 83. doi:10.1007/978-1-4020-9975-5_2. ISBN 978-1-4020-9974-8.
- Pershina, Valeria. "Theoretical Chemistry of the Heaviest Elements". In Schädel, Matthias; Shaughnessy, Dawn (eds.). The Chemistry of Superheavy Elements (2nd ed.). Springer Science & Business Media. p. 154. ISBN 9783642374661.
- "Element 114 is Named Flerovium and Element 116 is Named Livermorium". IUPAC. 30 May 2012.
- Wakhle, A.; Simenel, C.; Hinde, D. J.; et al. (2015). Simenel, C.; Gomes, P. R. S.; Hinde, D. J.; et al. (eds.). "Comparing Experimental and Theoretical Quasifission Mass Angle Distributions". European Physical Journal Web of Conferences. 86: 00061. Bibcode:2015EPJWC..8600061W. doi:10.1051/epjconf/20158600061. ISSN 2100-014X.
- Krämer, K. (2016). "Explainer: superheavy elements". Chemistry World. Retrieved 2020-03-15.
- "Discovery of Elements 113 and 115". Lawrence Livermore National Laboratory. Archived from the original on 2015-09-11. Retrieved 2020-03-15.
- Eliav, E.; Kaldor, U.; Borschevsky, A. (2018). "Electronic Structure of the Transactinide Atoms". In Scott, R. A. (ed.). Encyclopedia of Inorganic and Bioinorganic Chemistry. John Wiley & Sons. pp. 1–16. doi:10.1002/9781119951438.eibc2632. ISBN 978-1-119-95143-8.
- Oganessian, Yu. Ts.; Dmitriev, S. N.; Yeremin, A. V.; et al. (2009). "Attempt to produce the isotopes of element 108 in the fusion reaction 136Xe + 136Xe". Physical Review C. 79 (2): 024608. doi:10.1103/PhysRevC.79.024608. ISSN 0556-2813.
- Münzenberg, G.; Armbruster, P.; Folger, H.; et al. (1984). "The identification of element 108" (PDF). Zeitschrift für Physik A. 317 (2): 235–236. Bibcode:1984ZPhyA.317..235M. doi:10.1007/BF01421260. Archived from the original (PDF) on 7 June 2015. Retrieved 20 October 2012.
- Subramanian, S. (2019). "Making New Elements Doesn't Pay. Just Ask This Berkeley Scientist". Bloomberg Businessweek. Retrieved 2020-01-18.
- Ivanov, D. (2019). "Сверхтяжелые шаги в неизвестное" [Superheavy steps into the unknown]. N+1 (in Russian). Retrieved 2020-02-02.
- Hinde, D. (2014). "Something new and superheavy at the periodic table". The Conversation. Retrieved 2020-01-30.
- Krása, A. (2010). "Neutron Sources for ADS" (PDF). Czech Technical University in Prague. pp. 4–8. Retrieved October 20, 2019.
- Wapstra, A. H. (1991). "Criteria that must be satisfied for the discovery of a new chemical element to be recognized" (PDF). Pure and Applied Chemistry. 63 (6): 883. doi:10.1351/pac199163060879. ISSN 1365-3075. Retrieved 2020-08-28.
- Hyde, E. K.; Hoffman, D. C.; Keller, O. L. (1987). "A History and Analysis of the Discovery of Elements 104 and 105". Radiochimica Acta. 42 (2): 67–68. doi:10.1524/ract.19184.108.40.206. ISSN 2193-3405.
- Chemistry World (2016). "How to Make Superheavy Elements and Finish the Periodic Table [Video]". Scientific American. Retrieved 2020-01-27.
- Hoffman 2000, p. 334.
- Hoffman 2000, p. 335.
- Zagrebaev 2013, p. 3.
- Beiser 2003, p. 432.
- Staszczak, A.; Baran, A.; Nazarewicz, W. (2013). "Spontaneous fission modes and lifetimes of superheavy elements in the nuclear density functional theory". Physical Review C. 87 (2): 024320–1. arXiv:1208.1215. Bibcode:2013PhRvC..87b4320S. doi:10.1103/physrevc.87.024320. ISSN 0556-2813.
- Audi 2017, pp. 030001-128–030001-138.
- Beiser 2003, p. 439.
- Oganessian, Yu. Ts.; Rykaczewski, K. P. (2015). "A beachhead on the island of stability". Physics Today. 68 (8): 32–38. Bibcode:2015PhT....68h..32O. doi:10.1063/PT.3.2880. ISSN 0031-9228. OSTI 1337838.
- Grant, A. (2018). "Weighing the heaviest elements". Physics Today. doi:10.1063/PT.6.1.20181113a.
- Howes, L. (2019). "Exploring the superheavy elements at the end of the periodic table". Chemical & Engineering News. Retrieved 2020-01-27.
- Robinson, A. E. (2019). "The Transfermium Wars: Scientific Brawling and Name-Calling during the Cold War". Distillations. Retrieved 2020-02-22.
- "Популярная библиотека химических элементов. Сиборгий (экавольфрам)" [Popular library of chemical elements. Seaborgium (eka-tungsten)]. n-t.ru (in Russian). Retrieved 2020-01-07. Reprinted from "Экавольфрам" [Eka-tungsten]. Популярная библиотека химических элементов. Серебро — Нильсборий и далее [Popular library of chemical elements. Silver through nielsbohrium and beyond] (in Russian). Nauka. 1977.
- "Nobelium – Element information, properties and uses | Periodic Table". Royal Society of Chemistry. Retrieved 2020-03-01.
- Kragh 2018, pp. 38–39.
- Kragh 2018, p. 40.
- Ghiorso, A.; Seaborg, G. T.; Oganessian, Yu. Ts.; et al. (1993). "Responses on the report 'Discovery of the Transfermium elements' followed by reply to the responses by Transfermium Working Group" (PDF). Pure and Applied Chemistry. 65 (8): 1815–1824. doi:10.1351/pac199365081815. Archived (PDF) from the original on 25 November 2013. Retrieved 7 September 2016.
- Commission on Nomenclature of Inorganic Chemistry (1997). "Names and symbols of transfermium elements (IUPAC Recommendations 1997)" (PDF). Pure and Applied Chemistry. 69 (12): 2471–2474. doi:10.1351/pac199769122471.
- Hulet, E. K.; Lougheed, R.; Wild, J.; Landrum, J.; Stevenson, P.; Ghiorso, A.; Nitschke, J.; Otto, R.; et al. (1977). "Search for Superheavy Elements in the Bombardment of 248Cm with48Ca". Physical Review Letters. 39 (7): 385–389. Bibcode:1977PhRvL..39..385H. doi:10.1103/PhysRevLett.39.385.
- Armbruster, P.; Agarwal, YK; Brüchle, W; Brügger, M; Dufour, JP; Gaggeler, H; Hessberger, FP; Hofmann, S; et al. (1985). "Attempts to Produce Superheavy Elements by Fusion of 48Ca with 248Cm in the Bombarding Energy Range of 4.5–5.2 MeV/u". Physical Review Letters. 54 (5): 406–409. Bibcode:1985PhRvL..54..406A. doi:10.1103/PhysRevLett.54.406. PMID 10031507.
- Hofmann, Sigurd (1 December 2016). The discovery of elements 107 to 112 (PDF). Nobel Symposium NS160 – Chemistry and Physics of Heavy and Superheavy Elements. doi:10.1051/epjconf/201613106001.
- Smolanczuk, R. (1999). "Production mechanism of superheavy nuclei in cold fusion reactions". Physical Review C. 59 (5): 2634–2639. Bibcode:1999PhRvC..59.2634S. doi:10.1103/PhysRevC.59.2634.
- Ninov, Viktor; Gregorich, K.; Loveland, W.; Ghiorso, A.; Hoffman, D.; Lee, D.; Nitsche, H.; Swiatecki, W.; Kirbach, U.; Laue, C.; et al. (1999). "Observation of Superheavy Nuclei Produced in the Reaction of 86
". Physical Review Letters. 83 (6): 1104–1107. Bibcode:1999PhRvL..83.1104N. doi:10.1103/PhysRevLett.83.1104. (Retracted, see doi:10.1103/PhysRevLett.89.039901)
- Service, R. F. (1999). "Berkeley Crew Bags Element 118". Science. 284 (5421): 1751. doi:10.1126/science.284.5421.1751. S2CID 220094113.
- Public Affairs Department (2001-07-21). "Results of element 118 experiment retracted". Berkeley Lab. Archived from the original on 2008-01-29. Retrieved 2008-01-18.
- Dalton, R. (2002). "Misconduct: The stars who fell to Earth". Nature. 420 (6917): 728–729. Bibcode:2002Natur.420..728D. doi:10.1038/420728a. PMID 12490902. S2CID 4398009.
- Element 118 disappears two years after it was discovered. Physicsworld.com (August 2, 2001). Retrieved on 2012-04-02.
- Oganessian, Yu. Ts.; Utyonkov; Lobanov; Abdullin; Polyakov; Shirokovsky; Tsyganov; Gulbekian; Bogomolov; Gikal; Mezentsev; Iliev; Subbotin; Sukhov; Ivanov; Buklanov; Subotic; Itkis; Moody; Wild; Stoyer; Stoyer; Lougheed; Laue; Karelin; Tatarinov (2000). "Observation of the decay of 292116". Physical Review C. 63 (1): 011301. Bibcode:2001PhRvC..63a1301O. doi:10.1103/PhysRevC.63.011301.
- Oganessian, Yu. Ts.; Utyonkov, V.; Lobanov, Yu.; Abdullin, F.; Polyakov, A.; Shirokovsky, I.; Tsyganov, Yu.; Gulbekian, G.; Bogomolov, S.; Gikal, B. N.; et al. (2004). "Measurements of cross sections and decay properties of the isotopes of elements 112, 114, and 116 produced in the fusion reactions 233,238U, 242Pu, and 248Cm+48Ca" (PDF). Physical Review C. 70 (6): 064609. Bibcode:2004PhRvC..70f4609O. doi:10.1103/PhysRevC.70.064609.
- "Confirmed results of the 248Cm(48Ca,4n)292116 experiment" Archived 2016-01-30 at the Wayback Machine, Patin et al., LLNL report (2003). Retrieved 2008-03-03
- Oganessian, Yu. Ts.; Utyonkov, V. K.; Lobanov, Yu.; Abdullin, F.; Polyakov, A.; Shirokovsky, I.; Tsyganov, Yu.; Gulbekian, G.; Bogomolov, S.; Gikal, B.; Mezentsev, A.; Iliev, S.; Subbotin, V.; Sukhov, A.; Voinov, A.; Buklanov, G.; Subotic, K.; Zagrebaev, V.; Itkis, M.; Patin, J.; Moody, K.; Wild, J.; Stoyer, M.; Stoyer, N.; Shaughnessy, D.; Kenneally, J.; Wilk, P.; Lougheed, R.; Il’Kaev, R.; Vesnovskii, S. (2004). "Measurements of cross sections and decay properties of the isotopes of elements 112, 114, and 116 produced in the fusion reactions 233,238U, 242Pu, and 248Cm + 48Ca" (PDF). Physical Review C. 70 (6): 064609. Bibcode:2004PhRvC..70f4609O. doi:10.1103/PhysRevC.70.064609. Archived from the original (PDF) on May 28, 2008.
- Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Münzenberg, G.; Antalic, S.; Barth, W.; Burkhard, H. G.; Dahl, L.; Eberhardt, K.; Grzywacz, R.; Hamilton, J. H.; Henderson, R. A.; Kenneally, J. M.; Kindler, B.; Kojouharov, I.; Lang, R.; Lommel, B.; Miernik, K.; Miller, D.; Moody, K. J.; Morita, K.; Nishio, K.; Popeko, A. G.; Roberto, J. B.; Runke, J.; Rykaczewski, K. P.; Saro, S.; Scheidenberger, C.; Schött, H. J.; Shaughnessy, D. A.; Stoyer, M. A.; Thörle-Popiesch, P.; Tinschert, K.; Trautmann, N.; Uusitalo, J.; Yeremin, A. V. (2016). "Review of even element super-heavy nuclei and search for element 120". The European Physical Journal A. 2016 (52): 180. Bibcode:2016EPJA...52..180H. doi:10.1140/epja/i2016-16180-4. S2CID 124362890.
- Barber, R. C.; Karol, P. J.; Nakahara, H.; Vardaci, E.; Vogt, E. W. (2011). "Discovery of the elements with atomic numbers greater than or equal to 113 (IUPAC Technical Report)". Pure and Applied Chemistry. 83 (7): 1485. doi:10.1351/PAC-REP-10-05-01.
- Barber, R. C.; Gaeggeler, H. W.; Karol, P. J.; Nakahara, H.; Verdaci, E. & Vogt, E. (2009). "Discovery of the element with atomic number 112" (IUPAC Technical Report). Pure Appl. Chem. 81 (7): 1331. doi:10.1351/PAC-REP-08-03-05. S2CID 95703833.
- Hofmann, S.; Heinz, S.; Mann, R.; Maurer, J.; Khuyagbaatar, J.; Ackermann, D.; Antalic, S.; Barth, W.; Block, M.; Burkhard, H. G.; Comas, V. F.; Dahl, L.; Eberhardt, K.; Gostic, J.; Henderson, R. A.; Heredia, J. A.; Heßberger, F. P.; Kenneally, J. M.; Kindler, B.; Kojouharov, I.; Kratz, J. V.; Lang, R.; Leino, M.; Lommel, B.; Moody, K. J.; Münzenberg, G.; Nelson, S. L.; Nishio, K.; Popeko, A. G.; et al. (2012). "The reaction 48Ca + 248Cm → 296116* studied at the GSI-SHIP". The European Physical Journal A. 48 (5): 62. Bibcode:2012EPJA...48...62H. doi:10.1140/epja/i2012-12062-1. S2CID 121930293.
- Morita, K.; et al. (2014). "Measurement of the 248Cm + 48Ca fusion reaction products at RIKEN GARIS" (PDF). RIKEN Accel. Prog. Rep. 47: 11.
- Kaji, Daiya; Morita, Kosuke; Morimoto, Kouji; Haba, Hiromitsu; Asai, Masato; Fujita, Kunihiro; Gan, Zaiguo; Geissel, Hans; Hasebe, Hiroo; Hofmann, Sigurd; Huang, MingHui; Komori, Yukiko; Ma, Long; Maurer, Joachim; Murakami, Masashi; Takeyama, Mirei; Tokanai, Fuyuki; Tanaka, Taiki; Wakabayashi, Yasuo; Yamaguchi, Takayuki; Yamaki, Sayaka; Yoshida, Atsushi (2017). "Study of the Reaction 48Ca + 248Cm → 296Lv* at RIKEN-GARIS". Journal of the Physical Society of Japan. 86 (3): 034201–1–7. Bibcode:2017JPSJ...86c4201K. doi:10.7566/JPSJ.86.034201.
- Seaborg, Glenn T. (1974). "The Search for New Elements: The Projects of Today in a Larger Perspective". Physica Scripta. 10: 5–12. Bibcode:1974PhyS...10S...5S. doi:10.1088/0031-8949/10/A/001.
- Chatt, J. (1979). "Recommendations for the Naming of Elements of Atomic Numbers Greater than 100". Pure Appl. Chem. 51 (2): 381–384. doi:10.1351/pac197951020381.
- Folden, Cody (31 January 2009). "The Heaviest Elements in the Universe" (PDF). Saturday Morning Physics at Texas A&M. Archived from the original on August 10, 2014. Retrieved 9 March 2012.CS1 maint: unfit URL (link) "
- Hoffman, Darleane C. "Darmstadtium and Beyond". Chemical & Engineering News.
- Koppenol, W. H. (2002). "Naming of new elements(IUPAC Recommendations 2002)" (PDF). Pure and Applied Chemistry. 74 (5): 787. doi:10.1351/pac200274050787. S2CID 95859397.
- "Russian Physicists Will Suggest to Name Element 116 Moscovium". rian.ru. 2011. Retrieved 2011-05-08.: Mikhail Itkis, the vice-director of JINR stated: "We would like to name element 114 after Georgy Flerov – flerovium, and another one [element 116] – moscovium, not after Moscow, but after Moscow Oblast".
- Loss, Robert D.; Corish, John. "Names and symbols of the elements with atomic numbers 114 and 116 (IUPAC Recommendations 2012)" (PDF). IUPAC; Pure and Applied Chemistry. IUPAC. Retrieved 2 December 2015.
- "News: Start of the Name Approval Process for the Elements of Atomic Number 114 and 116". International Union of Pure and Applied Chemistry. Archived from the original on March 2, 2012. Retrieved February 22, 2012.
- Popeko, Andrey G. (2016). "Synthesis of superheavy elements" (PDF). jinr.ru. Joint Institute for Nuclear Research. Archived from the original (PDF) on 4 February 2018. Retrieved 4 February 2018.
- Zagrebaev, Valeriy; Karpov, Alexander; Greiner, Walter (2013). "Future of superheavy element research: Which nuclei could be synthesized within the next few years?" (PDF). Journal of Physics: Conference Series. 420. IOP Science. pp. 1–15. Retrieved 20 August 2013.
- Considine, Glenn D.; Kulik, Peter H. (2002). Van Nostrand's scientific encyclopedia (9th ed.). Wiley-Interscience. ISBN 978-0-471-33230-5. OCLC 223349096.
- Fleischmann, Martin; Pons, Stanley (1989). "Electrochemically induced nuclear fusion of deuterium". Journal of Electroanalytical Chemistry and Interfacial Electrochemistry. 261 (2): 301–308. doi:10.1016/0022-0728(89)80006-3.
- Barber, Robert C.; Gäggeler, Heinz W.; Karol, Paul J.; Nakahara, Hiromichi; Vardaci, Emanuele; Vogt, Erich (2009). "Discovery of the element with atomic number 112 (IUPAC Technical Report)" (PDF). Pure and Applied Chemistry. 81 (7): 1331. doi:10.1351/PAC-REP-08-03-05. S2CID 95703833.
- Armbruster, Peter & Munzenberg, Gottfried (1989). "Creating superheavy elements". Scientific American. 34: 36–42.
- Zagrebaev, V.; Greiner, W. (2008). "Synthesis of superheavy nuclei: A search for new production reactions". Physical Review C. 78 (3): 034610. arXiv:0807.2537. Bibcode:2008PhRvC..78c4610Z. doi:10.1103/PhysRevC.78.034610.
- "JINR Annual Reports 2000–2006". JINR. Retrieved 2013-08-27.
- Thayer, John S. (2010). "Relativistic Effects and the Chemistry of the Heavier Main Group Elements". Relativistic Methods for Chemists. Challenges and Advances in Computational Chemistry and Physics. 10. p. 83. doi:10.1007/978-1-4020-9975-5_2. ISBN 978-1-4020-9974-8. Missing or empty
- Faegri, K.; Saue, T. (2001). "Diatomic molecules between very heavy elements of group 13 and group 17: A study of relativistic effects on bonding". Journal of Chemical Physics. 115 (6): 2456. Bibcode:2001JChPh.115.2456F. doi:10.1063/1.1385366.
- Eichler, Robert (2015). "Gas phase chemistry with SHE – Experiments" (PDF). cyclotron.tamu.edu. Texas A & M University. Retrieved 27 April 2017.
- Nash, Clinton S.; Crockett, Wesley W. (2006). "An Anomalous Bond Angle in (116)H2. Theoretical Evidence for Supervalent Hybridization". The Journal of Physical Chemistry A. 110 (14): 4619–4621. Bibcode:2006JPCA..110.4619N. doi:10.1021/jp060888z. PMID 16599427.
- Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 117. ISBN 978-0-08-037941-8.
- Van WüLlen, C.; Langermann, N. (2007). "Gradients for two-component quasirelativistic methods. Application to dihalogenides of element 116". The Journal of Chemical Physics. 126 (11): 114106. Bibcode:2007JChPh.126k4106V. doi:10.1063/1.2711197. PMID 17381195.
- Düllmann, Christoph E. (2012). "Superheavy elements at GSI: a broad research program with element 114 in the focus of physics and chemistry". Radiochimica Acta. 100 (2): 67–74. doi:10.1524/ract.2011.1842. S2CID 100778491.
- Eichler, Robert (2013). "First foot prints of chemistry on the shore of the Island of Superheavy Elements". Journal of Physics: Conference Series. 420 (1): 012003. arXiv:1212.4292. Bibcode:2013JPhCS.420a2003E. doi:10.1088/1742-6596/420/1/012003. S2CID 55653705.
- Moody, Ken (2013-11-30). "Synthesis of Superheavy Elements". In Schädel, Matthias; Shaughnessy, Dawn (eds.). The Chemistry of Superheavy Elements (2nd ed.). Springer Science & Business Media. pp. 24–8. ISBN 9783642374661.
- Audi, G.; Kondev, F. G.; Wang, M.; et al. (2017). "The NUBASE2016 evaluation of nuclear properties". Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.
- Beiser, A. (2003). Concepts of modern physics (6th ed.). McGraw-Hill. ISBN 978-0-07-244848-1. OCLC 48965418.
- Hoffman, D. C.; Ghiorso, A.; Seaborg, G. T. (2000). The Transuranium People: The Inside Story. World Scientific. ISBN 978-1-78-326244-1.
- Kragh, H. (2018). From Transuranic to Superheavy Elements: A Story of Dispute and Creation. Springer. ISBN 978-3-319-75813-8.
- Zagrebaev, V.; Karpov, A.; Greiner, W. (2013). "Future of superheavy element research: Which nuclei could be synthesized within the next few years?". Journal of Physics: Conference Series. 420 (1): 012001. arXiv:1207.5700. Bibcode:2013JPhCS.420a2001Z. doi:10.1088/1742-6596/420/1/012001. ISSN 1742-6588. S2CID 55434734.
|Wikimedia Commons has media related to Livermorium.|
- Livermorium at The Periodic Table of Videos (University of Nottingham)
- CERN Courier – Second postcard from the island of stability
- Livermorium at WebElements.com