User:Praseodymium-141/Unbipentium

From Wikipedia, the free encyclopedia
Unbipentium, 00Ubp
Unbipentium
Pronunciation/ˌuːnbaɪˈpɛntiəm/ ​(OON-by-PEN-tee-əm)
Alternative nameselement 125, eka-neptunium
Unbipentium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
—
↑
Ubp
↓
—
unbiquadium ← unbipentium → unbihexium
Groupg-block groups (no number)
Periodperiod 8 (theoretical, extended table)
Block  g-block
Electron configurationpredictions vary, see text
Physical properties
unknown
Phase at STPunknown
Atomic properties
Oxidation states(+1), (+6), (+7) (predicted)[1]
History
NamingIUPAC systematic element name
Isotopes of unbipentium
Template:infobox unbipentium isotopes does not exist
 Category: Unbipentium
| references

Unbipentum, also known as element 125 or eka-neptunium, is the hypothetical chemical element in the periodic table with the placeholder symbol of Ubt and atomic number 125[2]. Unbipentium and Ubp are the temporary systematic IUPAC name and symbol respectively, which are used until the element is discovered, confirmed, and a permanent name is decided upon. In the periodic table of the elements, it is expected to follow unbiquadium as the second element of the superactinides and the fifth element of the 8th period. Similarly to unbibium and unbiunium, it is expected to fall within the range of the island of stability.

Since there are no natural isotopes of this element, it would have to be generated (synthesized) in an artificial way through nuclear reactions. The name is provisional and is derived from the ordinal number. As of 2022, the synthesis of unbipentium has only been attempted once, and no naturally occurring isotopes have been found to exist. There are currently no plans to attempt to synthesize unbipentium.

Unbipentium is expected to be in a new group of elements called superactinides[3]. These should behave differently from other groups of elements.

Chemically, unbipentium is expected to show some resemblance to promethium and neptunium. However, due to relativistic effects, some of these properties may differ from expected. Unbipentium is possibly the fifth element to have a G orbital, which would fill the 5th shell with three additional electrons.

Introduction[edit]

This section is transcluded from Introduction to the heaviest elements. (edit | history)
"Transactinide element" redirects here. Not to be confused with Transuranium element.
Superheavy elements
in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
Z ≥ 104 (Rf)

Superheavy elements, also known as transactinide elements, transactinides, or super-heavy elements, or superheavies for short, are the chemical elements with atomic number greater than 103. The superheavy elements are those beyond the actinides in the periodic table; the last actinide is lawrencium (atomic number 103). By definition, superheavy elements are also transuranium elements, i.e., having atomic numbers greater than that of uranium (92). Depending on the definition of group 3 adopted by authors, lawrencium may also be included to complete the 6d series.[4][5][6][7]

Glenn T. Seaborg first proposed the actinide concept, which led to the acceptance of the actinide series. He also proposed a transactinide series ranging from element 104 to 121 and a superactinide series approximately spanning elements 122 to 153 (though more recent work suggests the end of the superactinide series to occur at element 157 instead). The transactinide seaborgium was named in his honor.[8][9]

Superheavies are radioactive and have only been obtained synthetically in laboratories. No macroscopic sample of any of these elements has ever been produced. Superheavies are all named after physicists and chemists or important locations involved in the synthesis of the elements.

IUPAC defines an element to exist if its lifetime is longer than 10−14 second, which is the time it takes for the atom to form an electron cloud.[10]

The known superheavies form part of the 6d and 7p series in the periodic table. Except for rutherfordium and dubnium (and lawrencium if it is included), even the longest-lived known isotopes of superheavies have half-lives of minutes or less. The element naming controversy involved elements 102–109. Some of these elements thus used systematic names for many years after their discovery was confirmed. (Usually the systematic names are replaced with permanent names proposed by the discoverers relatively soon after a discovery has been confirmed.)

Introduction[edit]

Synthesis of superheavy nuclei[edit]

See also: Nucleosynthesis and Nuclear reaction
A graphic depiction of a nuclear fusion reaction
A graphic depiction of a nuclear fusion reaction. Two nuclei fuse into one, emitting a neutron. Reactions that created new elements to this moment were similar, with the only possible difference that several singular neutrons sometimes were released, or none at all.

A superheavy[a] atomic nucleus is created in a nuclear reaction that combines 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.[16] 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.[17] The energy applied to the beam nuclei to accelerate them can cause them to reach speeds as high as one-tenth of the speed of light. However, if too much energy is applied, the beam nucleus can fall apart.[17]

Coming close enough alone is not enough for two nuclei to fuse: when two nuclei approach each other, they usually remain together for about 10−20 second and then part ways (not necessarily in the same composition as before the reaction) rather than form a single nucleus.[17][18] This happens because during the attempted formation of a single nucleus, electrostatic repulsion tears apart the nucleus that is being formed.[17] Each pair of a target and a beam is characterized by its cross section—the probability that fusion will occur if two nuclei approach one another expressed in terms of the transverse area that the incident particle must hit in order for the fusion to occur.[c] This fusion may occur as a result of the quantum effect in which nuclei can tunnel through electrostatic repulsion. If the two nuclei can stay close for past that phase, multiple nuclear interactions result in redistribution of energy and an energy equilibrium.[17]

External videos
video icon Visualization of unsuccessful nuclear fusion, based on calculations from the Australian National University[20]

The resulting merger is an excited state[21]—termed a compound nucleus—and thus it is very unstable.[17] To reach a more stable state, the temporary merger may fission without formation of a more stable nucleus.[22] Alternatively, the compound nucleus may eject a few neutrons, which would carry away the excitation energy; if the latter is not sufficient for a neutron expulsion, the merger would produce a gamma ray. This happens in about 10−16 second after the initial nuclear collision and results in creation of a more stable nucleus.[22] The definition by the IUPAC/IUPAP Joint Working Party (JWP) 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.[23][d]

Decay and detection[edit]

See also: Gaseous ionization detector

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.[25] 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.[25] The transfer takes about 10−6 second; in order to be detected, the nucleus must survive this long.[28] The nucleus is recorded again once its decay is registered, and the location, the energy, and the time of the decay are measured.[25]

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, and its range is not limited.[29] Total binding energy provided by the strong interaction increases linearly with the number of nucleons, whereas electrostatic repulsion increases with the square of the atomic number, i.e. the latter grows faster and becomes increasingly important for heavy and superheavy nuclei.[30][31] Superheavy nuclei are thus theoretically predicted[32] and have so far been observed[33] to predominantly decay via decay modes that are caused by such repulsion: alpha decay and spontaneous fission.[f] Almost all alpha emitters have over 210 nucleons,[35] and the lightest nuclide primarily undergoing spontaneous fission has 238.[36] In both decay modes, nuclei are inhibited from decaying by corresponding energy barriers for each mode, but they can be tunneled through.[30][31]

Apparatus for creation of superheavy elements
Scheme of an apparatus for creation of superheavy elements, based on the Dubna Gas-Filled Recoil Separator set up in the Flerov Laboratory of Nuclear Reactions in JINR. The trajectory within the detector and the beam focusing apparatus changes because of a dipole magnet in the former and quadrupole magnets in the latter.[37]

Alpha particles are commonly produced in radioactive decays because mass of an alpha particle per nucleon is small enough to leave some energy for the alpha particle to be used as kinetic energy to leave the nucleus.[38] Spontaneous fission is caused by electrostatic repulsion tearing the nucleus apart and produces various nuclei in different instances of identical nuclei fissioning.[31] As the atomic number increases, spontaneous fission rapidly becomes more important: spontaneous fission partial half-lives decrease by 23 orders of magnitude from uranium (element 92) to nobelium (element 102),[39] and by 30 orders of magnitude from thorium (element 90) to fermium (element 100).[40] The earlier liquid drop model thus suggested that spontaneous fission would occur nearly instantly due to disappearance of the fission barrier for nuclei with about 280 nucleons.[31][41] The later nuclear shell model suggested that nuclei with about 300 nucleons would form an island of stability in which nuclei will be more resistant to spontaneous fission and will primarily undergo alpha decay with longer half-lives.[31][41] Subsequent discoveries suggested that the predicted island might be further than originally anticipated; they also showed that nuclei intermediate between the long-lived actinides and the predicted island are deformed, and gain additional stability from shell effects.[42] Experiments on lighter superheavy nuclei,[43] as well as those closer to the expected island,[39] have shown greater than previously anticipated stability against spontaneous fission, showing the importance of shell effects on nuclei.[g]

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 easily determined.[h] (That all decays within a decay chain were indeed related to each other is established by the location of these decays, which must be in the same place.)[25] The known nucleus can be recognized by the specific characteristics of decay it undergoes such as decay energy (or more specifically, the kinetic energy of the emitted particle).[i] Spontaneous fission, however, produces various nuclei as products, so the original nuclide cannot be determined from its daughters.[j]

The information available to physicists aiming to synthesize a superheavy element 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.[k]

History[edit]

Early predictions[edit]

The heaviest element known at the end of the 19th century was uranium, with an atomic mass of about 240 (now known to be 238) amu. Accordingly, it was placed in the last row of the periodic table; this fueled speculation about the possible existence of elements heavier than uranium and why A = 240 seemed to be the limit. Following the discovery of the noble gases, beginning with argon in 1895, the possibility of heavier members of the group was considered. Danish chemist Julius Thomsen proposed in 1895 the existence of a sixth noble gas with Z = 86, A = 212 and a seventh with Z = 118, A = 292, the last closing a 32-element period containing thorium and uranium.[54] In 1913, Swedish physicist Johannes Rydberg extended Thomsen's extrapolation of the periodic table to include even heavier elements with atomic numbers up to 460, but he did not believe that these superheavy elements existed or occurred in nature.[55]

In 1914, German physicist Richard Swinne proposed that elements heavier than uranium, such as those around Z = 108, could be found in cosmic rays. He suggested that these elements may not necessarily have decreasing half-lives with increasing atomic number, leading to speculation about the possibility of some longer-lived elements at Z = 98–102 and Z = 108–110 (though separated by short-lived elements). Swinne published these predictions in 1926, believing that such elements might exist in Earth's core, iron meteorites, or the ice caps of Greenland where they had been locked up from their supposed cosmic origin.[56]

Discoveries[edit]

Work performed from 1961 to 2013 at four labs – Lawrence Berkeley National Laboratory in the US, the Joint Institute for Nuclear Research in the USSR (later Russia), the GSI Helmholtz Centre for Heavy Ion Research in Germany, and Riken in Japan – identified and confirmed the elements lawrencium to oganesson according to the criteria of the IUPAC–IUPAP Transfermium Working Groups and subsequent Joint Working Parties. These discoveries complete the seventh row of the periodic table. The next two elements, ununennium (Z = 119) and unbinilium (Z = 120), have not yet been synthesized. They would begin an eighth period.

List of elements[edit]

Characteristics[edit]

Due to their short half-lives (for example, the most stable known isotope of seaborgium has a half-life of 14 minutes, and half-lives decrease with increasing atomic number) and the low yield of the nuclear reactions that produce them, new methods have had to be created to determine their gas-phase and solution chemistry based on very small samples of a few atoms each. Relativistic effects become very important in this region of the periodic table, causing the filled 7s orbitals, empty 7p orbitals, and filling 6d orbitals to all contract inward toward the atomic nucleus. This causes a relativistic stabilization of the 7s electrons and makes the 7p orbitals accessible in low excitation states.[9]

Elements 103 to 112, lawrencium to copernicium, form the 6d series of transition elements. Experimental evidence shows that elements 103–108 behave as expected for their position in the periodic table, as heavier homologs of lutetium through osmium. They are expected to have ionic radii between those of their 5d transition metal homologs and their actinide pseudohomologs: for example, Rf4+ is calculated to have ionic radius 76 pm, between the values for Hf4+ (71 pm) and Th4+ (94 pm). Their ions should also be less polarizable than those of their 5d homologs. Relativistic effects are expected to reach a maximum at the end of this series, at roentgenium (element 111) and copernicium (element 112). Nevertheless, many important properties of the transactinides are still not yet known experimentally, though theoretical calculations have been performed.[9]

Elements 113 to 118, nihonium to oganesson, should form a 7p series, completing the seventh period in the periodic table. Their chemistry will be greatly influenced by the very strong relativistic stabilization of the 7s electrons and a strong spin–orbit coupling effect "tearing" the 7p subshell apart into two sections, one more stabilized (7p1/2, holding two electrons) and one more destabilized (7p3/2, holding four electrons). Lower oxidation states should be stabilized here, continuing group trends, as both the 7s and 7p1/2 electrons exhibit the inert-pair effect. These elements are expected to largely continue to follow group trends, though with relativistic effects playing an increasingly larger role. In particular, the large 7p splitting results in an effective shell closure at flerovium (element 114) and a hence much higher than expected chemical activity for oganesson (element 118).[9]

Element 118 is the last element that has been synthesized. The next two elements, 119 and 120, should form an 8s series and be an alkali and alkaline earth metal respectively. The 8s electrons are expected to be relativistically stabilized, so that the trend toward higher reactivity down these groups will reverse and the elements will behave more like their period 5 homologs, rubidium and strontium. The 7p3/2 orbital is still relativistically destabilized, potentially giving these elements larger ionic radii and perhaps even being able to participate chemically. In this region, the 8p electrons are also relativistically stabilized, resulting in a ground-state 8s28p1 valence electron configuration for element 121. Large changes are expected to occur in the subshell structure in going from element 120 to element 121: for example, the radius of the 5g orbitals should drop drastically, from 25 Bohr units in element 120 in the excited [Og] 5g1 8s1 configuration to 0.8 Bohr units in element 121 in the excited [Og] 5g1 7d1 8s1 configuration, in a phenomenon called "radial collapse". Element 122 should add either a further 7d or a further 8p electron to element 121's electron configuration. Elements 121 and 122 should be similar to actinium and thorium respectively.[9]

At element 121, the superactinide series is expected to begin, when the 8s electrons and the filling 8p1/2, 7d3/2, 6f5/2, and 5g7/2 subshells determine the chemistry of these elements. Complete and accurate calculations are not available for elements beyond 123 because of the extreme complexity of the situation:[57] the 5g, 6f, and 7d orbitals should have about the same energy level, and in the region of element 160 the 9s, 8p3/2, and 9p1/2 orbitals should also be about equal in energy. This will cause the electron shells to mix so that the block concept no longer applies very well, and will also result in novel chemical properties that will make positioning these elements in a periodic table very difficult.[9]

Beyond superheavy elements[edit]

It has been suggested that elements beyond Z = 126 be called beyond superheavy elements.[58] Other sources refer to elements around Z = 164 as hyperheavy elements.[59]

See also[edit]

Notes[edit]

  1. ^ 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[11] or 112;[12] sometimes, the term is presented an equivalent to the term "transactinide", which puts an upper limit before the beginning of the hypothetical superactinide series).[13] 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.
  2. ^ In 2009, a team at the 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.[14] 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.[15]
  3. ^ The amount of energy applied to the beam particle to accelerate it can also influence the value of cross section. For example, in the 28
    14    Si
     + 1
    0    n
     → 28
    13    Al
     + 1
    1    p
     reaction, cross section changes smoothly from 370 mb at 12.3 MeV to 160 mb at 18.3 MeV, with a broad peak at 13.5 MeV with the maximum value of 380 mb.[19]
  4. ^ This figure also marks the generally accepted upper limit for lifetime of a compound nucleus.[24]
  5. ^ 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.[26] 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.[27]
  6. ^ Not all decay modes are caused by electrostatic repulsion. For example, beta decay is caused by the weak interaction.[34]
  7. ^ It was already known by the 1960s that ground states of nuclei differed in energy and shape as well as that certain magic numbers of nucleons corresponded to greater stability of a nucleus. However, it was assumed that there was no nuclear structure in superheavy nuclei as they were too deformed to form one.[39]
  8. ^ 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 superheavy nuclei.[44] The first direct measurement of mass of a superheavy nucleus was reported in 2018 at LBNL.[45] 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).[46]
  9. ^ If the decay occurred in a vacuum, then since total momentum of an isolated system before and after the decay must be preserved, the daughter nucleus would also receive a small velocity. The ratio of the two velocities, and accordingly the ratio of the kinetic energies, would thus be inverse to the ratio of the two masses. The decay energy equals the sum of the known kinetic energy of the alpha particle and that of the daughter nucleus (an exact fraction of the former).[35] The calculations hold for an experiment as well, but the difference is that the nucleus does not move after the decay because it is tied to the detector.
  10. ^ Spontaneous fission was discovered by Soviet physicist Georgy Flerov,[47] a leading scientist at JINR, and thus it was a "hobbyhorse" for the facility.[48] 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.[24] They thus preferred to link new isotopes to the already known ones by successive alpha decays.[47]
  11. ^ For instance, element 102 was mistakenly identified in 1957 at the Nobel Institute of Physics in Stockholm, Stockholm County, Sweden.[49] 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.[50] The following year, RL was unable to reproduce the Swedish results and announced instead their synthesis of the element; that claim was also disproved later.[50] JINR insisted that they were the first to create the element and suggested a name of their own for the new element, joliotium;[51] the Soviet name was also not accepted (JINR later referred to the naming of the element 102 as "hasty").[52] This name was proposed to IUPAC in a written response to their ruling on priority of discovery claims of elements, signed 29 September 1992.[52] The name "nobelium" remained unchanged on account of its widespread usage.[53]

References[edit]

  1. ^ Pyykkö, Pekka (2011). "A suggested periodic table up to Z ≤ 172, based on Dirac–Fock calculations on atoms and ions". Physical Chemistry Chemical Physics. 13 (1): 161–8. Bibcode:2011PCCP...13..161P. doi:10.1039/c0cp01575j. PMID 20967377.
  2. ^ "Unbipentium". 7 May 2020.
  3. ^ see superactinide
  4. ^ a b Neve, Francesco (2022). "Chemistry of superheavy transition metals". Journal of Coordination Chemistry. 75 (17–18): 2287–2307. doi:10.1080/00958972.2022.2084394. S2CID 254097024.
  5. ^ a b Mingos, Michael (1998). Essential Trends in Inorganic Chemistry. Oxford University Press. p. 387. ISBN 978-0-19-850109-1.
  6. ^ "A New Era of Discovery: the 2023 Long Range Plan for Nuclear Science" (PDF). U.S. Department of Energy. October 2023. Archived from the original (PDF) on 2023-10-05. Retrieved 20 October 2023 – via OSTI. Superheavy elements (Z > 102) are teetering at the limits of mass and charge.
  7. ^ Kragh, Helge (2017). "The search for superheavy elements: Historical and philosophical perspectives". arXiv:1708.04064 [physics.hist-ph].
  8. ^ IUPAC Provisional Recommendations for the Nomenclature of Inorganic Chemistry (2004) (online draft of an updated version of the "Red Book" IR 3-6) Archived October 27, 2006, at the Wayback Machine
  9. ^ a b c d e f Morss, Lester R.; Edelstein, Norman M.; Fuger, Jean, eds. (2006). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer. ISBN 978-1-4020-3555-5.
  10. ^ "Kernchemie". www.kernchemie.de.
  11. ^ Krämer, K. (2016). "Explainer: superheavy elements". Chemistry World. Retrieved 2020-03-15.
  12. ^ "Discovery of Elements 113 and 115". Lawrence Livermore National Laboratory. Archived from the original on 2015-09-11. Retrieved 2020-03-15.
  13. ^ 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. S2CID 127060181.
  14. ^ 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.
  15. ^ 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. S2CID 123288075. Archived from the original (PDF) on 7 June 2015. Retrieved 20 October 2012.
  16. ^ Subramanian, S. (28 August 2019). "Making New Elements Doesn't Pay. Just Ask This Berkeley Scientist". Bloomberg Businessweek. Retrieved 2020-01-18.
  17. ^ a b c d e f Ivanov, D. (2019). "Сверхтяжелые шаги в неизвестное" [Superheavy steps into the unknown]. nplus1.ru (in Russian). Retrieved 2020-02-02.
  18. ^ Hinde, D. (2017). "Something new and superheavy at the periodic table". The Conversation. Retrieved 2020-01-30.
  19. ^ Kern, B. D.; Thompson, W. E.; Ferguson, J. M. (1959). "Cross sections for some (n, p) and (n, α) reactions". Nuclear Physics. 10: 226–234. Bibcode:1959NucPh..10..226K. doi:10.1016/0029-5582(59)90211-1.
  20. ^ 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. hdl:1885/148847. ISSN 2100-014X.
  21. ^ "Nuclear Reactions" (PDF). pp. 7–8. Retrieved 2020-01-27. Published as Loveland, W. D.; Morrissey, D. J.; Seaborg, G. T. (2005). "Nuclear Reactions". Modern Nuclear Chemistry. John Wiley & Sons, Inc. pp. 249–297. doi:10.1002/0471768626.ch10. ISBN 978-0-471-76862-3.
  22. ^ a b Krása, A. (2010). "Neutron Sources for ADS". Faculty of Nuclear Sciences and Physical Engineering. Czech Technical University in Prague: 4–8. S2CID 28796927.
  23. ^ 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. S2CID 95737691.
  24. ^ a b 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.1987.42.2.57. ISSN 2193-3405. S2CID 99193729.
  25. ^ a b c d Chemistry World (2016). "How to Make Superheavy Elements and Finish the Periodic Table [Video]". Scientific American. Retrieved 2020-01-27.
  26. ^ Hoffman, Ghiorso & Seaborg 2000, p. 334.
  27. ^ Hoffman, Ghiorso & Seaborg 2000, p. 335.
  28. ^ Zagrebaev, Karpov & Greiner 2013, p. 3.
  29. ^ Beiser 2003, p. 432.
  30. ^ a b Pauli, N. (2019). "Alpha decay" (PDF). Introductory Nuclear, Atomic and Molecular Physics (Nuclear Physics Part). Université libre de Bruxelles. Retrieved 2020-02-16.
  31. ^ a b c d e Pauli, N. (2019). "Nuclear fission" (PDF). Introductory Nuclear, Atomic and Molecular Physics (Nuclear Physics Part). Université libre de Bruxelles. Retrieved 2020-02-16.
  32. ^ 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.
  33. ^ Audi et al. 2017, pp. 030001-129–030001-138.
  34. ^ Beiser 2003, p. 439.
  35. ^ a b Beiser 2003, p. 433.
  36. ^ Audi et al. 2017, p. 030001-125.
  37. ^ Aksenov, N. V.; Steinegger, P.; Abdullin, F. Sh.; et al. (2017). "On the volatility of nihonium (Nh, Z = 113)". The European Physical Journal A. 53 (7): 158. Bibcode:2017EPJA...53..158A. doi:10.1140/epja/i2017-12348-8. ISSN 1434-6001. S2CID 125849923.
  38. ^ Beiser 2003, p. 432–433.
  39. ^ a b c Oganessian, Yu. (2012). "Nuclei in the "Island of Stability" of Superheavy Elements". Journal of Physics: Conference Series. 337 (1): 012005-1–012005-6. Bibcode:2012JPhCS.337a2005O. doi:10.1088/1742-6596/337/1/012005. ISSN 1742-6596.
  40. ^ Moller, P.; Nix, J. R. (1994). Fission properties of the heaviest elements (PDF). Dai 2 Kai Hadoron Tataikei no Simulation Symposium, Tokai-mura, Ibaraki, Japan. University of North Texas. Retrieved 2020-02-16.
  41. ^ a b Oganessian, Yu. Ts. (2004). "Superheavy elements". Physics World. 17 (7): 25–29. doi:10.1088/2058-7058/17/7/31. Retrieved 2020-02-16.
  42. ^ Schädel, M. (2015). "Chemistry of the superheavy elements". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences. 373 (2037): 20140191. Bibcode:2015RSPTA.37340191S. doi:10.1098/rsta.2014.0191. ISSN 1364-503X. PMID 25666065.
  43. ^ Hulet, E. K. (1989). Biomodal spontaneous fission. 50th Anniversary of Nuclear Fission, Leningrad, USSR. Bibcode:1989nufi.rept...16H.
  44. ^ 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. S2CID 119531411.
  45. ^ Grant, A. (2018). "Weighing the heaviest elements". Physics Today. doi:10.1063/PT.6.1.20181113a. S2CID 239775403.
  46. ^ Howes, L. (2019). "Exploring the superheavy elements at the end of the periodic table". Chemical & Engineering News. Retrieved 2020-01-27.
  47. ^ a b Robinson, A. E. (2019). "The Transfermium Wars: Scientific Brawling and Name-Calling during the Cold War". Distillations. Retrieved 2020-02-22.
  48. ^ "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.
  49. ^ "Nobelium - Element information, properties and uses | Periodic Table". Royal Society of Chemistry. Retrieved 2020-03-01.
  50. ^ a b Kragh 2018, pp. 38–39.
  51. ^ Kragh 2018, p. 40.
  52. ^ a b 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. S2CID 95069384. Archived (PDF) from the original on 25 November 2013. Retrieved 7 September 2016.
  53. ^ 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.
  54. ^ Kragh 2018, p. 6
  55. ^ Kragh 2018, p. 7
  56. ^ Kragh 2018, p. 10
  57. ^ van der Schoor, K. (2016). Electronic structure of element 123 (PDF) (Thesis). Rijksuniversiteit Groningen.
  58. ^ Hofmann, Sigurd (2019). "Synthesis and properties of isotopes of the transactinides". Radiochimica Acta. 107 (9–11): 879–915. doi:10.1515/ract-2019-3104. S2CID 203848120.
  59. ^ Laforge, Evan; Price, Will; Rafelski, Johann (2023). "Superheavy elements and ultradense matter". The European Physical Journal Plus. 138 (9). arXiv:2306.11989. doi:10.1140/epjp/s13360-023-04454-8.

Bibliography[edit]




History[edit]

Every element from mendelevium onward was produced in fusion-evaporation reactions, culminating in the discovery of the heaviest known element oganesson in 2002[1][2] and most recently tennessine in 2010.[3] These reactions approached the limit of current technology; for example, the synthesis of tennessine required 22 milligrams of 249Bk and an intense 48Ca beam for six months. The intensity of beams in superheavy element research cannot exceed 1012 projectiles per second without damaging the target and detector, and producing larger quantities of increasingly rare and unstable actinide targets is impractical.[4] Consequently, future experiments must be done at facilities such as the under-construction superheavy element factory (SHE-factory) at the Joint Institute for Nuclear Research (JINR) or RIKEN, which will allow experiments to run for longer stretches of time with increased detection capabilities and enable otherwise inaccessible reactions.[5] Even so, it will likely be a great challenge to continue past elements 120 or perhaps 121 given short predicted half-lives and low predicted cross sections.[3][6]

Only one sythesis attempt has been made,[7] but there will most likely be none in the near future; the discoveries of elements 119 and 120 as well as new isotopes of known superheavy elements closer to the predicted island of stability are currently more feasible and of greater interest.[6] It may also be possible that fusion-evaporation reactions may not work at all, and new methods of synthesis such as multinucleon transfer or inverse quasi-fission reactions may be required, though the production of lighter superheavy nuclei with 102 < Z < 106 is more favorable, especially if shell effects are weaker than predicted or otherwise nonexistent.

Naming[edit]

The name unbipentium (literally meaning one-two-five-ium[8][9]) is a systematic element name, used as a placeholder until it is confirmed by other research groups and the IUPAC decides on a name. Usually, the name suggested by the discoverer(s) is chosen[9][10]. Using Mendeleev's nomenclature for unnamed and undiscovered elements, unbipentium should instead be known as eka-neptunium.[11] However, such an extrapolation might not work for g-block elements with no known congeners, and eka-neptunium would instead refer to element 145[12] or 147[13] when the term is meant to denote the element directly below neptunium. After the recommendations of the IUPAC in 1979, the element has since been largely referred to as unbipentium with the atomic symbol of (Ubp),[14] as its temporary name until the element is officially discovered and synthesized, and a permanent name is decided on. Scientists largely ignore this naming convention, and instead simply refer to unbipentium as "element 125" with the symbol of (125), Dvi-promethium, or sometimes even E125 or 125.[15]

Predicted properties[edit]

Nuclear stability[edit]

Predicted decay modes of superheavy nuclei. The line of synthesized proton-rich nuclei is expected to be broken soon after Z = 120, because of the shortening half-lives until around Z = 124, the increasing contribution of spontaneous fission instead of alpha decay from Z = 122 onward until it dominates from Z = 125, and the proton drip line around Z = 130. The white ring denotes the expected location of the island of stability; the two squares outlined in white denote 291Cn and 293Cn, predicted to be the longest-lived nuclides on the island with half-lives of centuries or millennia.[6]

No superactinide has ever been observed, and it is not known whether the existence of such a heavy atom is physically possible. The stability of nuclei decreases greatly with the increase in atomic number after plutonium, the heaviest primordial element, so that all isotopes with an atomic number above 101 decay radioactively with a half-life under a day, with an exception of dubnium-268. No elements with atomic numbers above 82 (after lead) have stable isotopes.[16] Nevertheless, because of reasons not very well understood yet, there is a slight increased nuclear stability around atomic numbers 110–114, which leads to the appearance of what is known in nuclear physics as the "island of stability". This concept, proposed by University of California professor Glenn Seaborg, explains why superheavy elements last longer than predicted.[17]

In this region of the periodic table, N = 184 and N = 228 have been suggested as closed neutron shells, and various atomic numbers have been proposed as closed proton shells, such as Z = 114, 120, 122, 124, and 126. The island of stability would be characterized by longer half-lives of nuclei located near these magic numbers, though the extent of stabilizing effects is uncertain due to predictions of weakening of the proton shell closures and possible loss of double magicity.[18] More recent research predicts the island of stability to instead be centered at beta-stable copernicium isotopes 291Cn and 293Cn,[6] which would place unbipentium well above the island and result in short half-lives regardless of shell effects.

The layered model of the atomic nucleus predicts the existence of magic numbers[19] per type of nucleons due to the stratification of neutrons and protons in quantum energy levels in the nucleus postulated by this model, as is what it happens for the electrons at the level of the atom; one of these magic numbers is 126, observed for neutrons but not yet for protons, while the following magic number, 184, has never been observed: nuclides with around 126 protons are expected to be (unbihexium) and 184 neutrons are appreciably more stable than neighboring nuclides, with perhaps half-lives greater than a second, which would constitute an "island of stability". The difficulty is that, for superheavy atoms, the determination of the magic numbers seems more delicate than for the light atoms,[20] so that, according to the models, the following magic number should be sought for Z between 114 and 126. The unbipentium is one of the elements that would be possible to produce, with current techniques, in the island of stability; the particular stability of these isotopes would be due to a quantum coupling effect of ω[21] mesons, one of the nine so-called “tasteless” mesons.

Chemical properties[edit]

Unbipentium is expected to be the fifth member of a superactinide series. It should have similarities to promethium and neptunium. It is also predicted to be the fifth member of a new block of valence g-electron atoms,[22] although the 5g orbital is not expected to start filling until unbipentium. In the superactinide series, the Aufbau principle is expected to break down due to relativistic effects, and an overlap of the 5g, 6f, 7d, and 8p orbitals is expected, rendering predictions of chemical and atomic properties of these elements very difficult.[22]

Synthesis attempts[edit]

The synthesis of unbipentium was first attempted in 1977 by bombarding a target of americium-238 with zinc-65 ions at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany:

  • 243Am + 66,68Zn → 309,311Ubp

No atoms were identified.[23]

Notes[edit]

See also[edit]

References[edit]

  1. ^ Oganessian, YT; et al. (2002). "Element 118: results from the first 249
    Cf
     + 48
    Ca
     experiment"    . Communication of the Joint Institute for Nuclear Research. Archived from the original on 22 July 2011.
  2. ^ "Livermore scientists team with Russia to discover element 118". Livermore press release. 3 December 2006. Retrieved 18 January 2008.
  3. ^ a b Oganessian, Yu. Ts.; Abdullin, F. Sh.; Bailey, P. D.; et al. (2010). "Synthesis of a New Element with Atomic Number Z = 117". Physical Review Letters. 104 (14): 142502-1–142502-4. Bibcode:2010PhRvL.104n2502O. doi:10.1103/PhysRevLett.104.142502. PMID 20481935.
  4. ^ Roberto, JB (2015). "Actinide Targets for Super-Heavy Element Research" (PDF). cyclotron.tamu.edu. Texas A & M University. Retrieved 30 October 2018.
  5. ^ Hagino, Kouichi; Hofmann, Sigurd; Miyatake, Hiroari; Nakahara, Hiromichi (2012). "平成23年度 研究業績レビュー（中間レビュー）の実施について" (PDF). www.riken.jp. RIKEN. Retrieved 5 May 2017.
  6. ^ a b c d 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. 420 (1): 012001. arXiv:1207.5700. Bibcode:2013JPhCS.420a2001Z. doi:10.1088/1742-6596/420/1/012001. S2CID 55434734.
  7. ^ Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements (New ed.). New York, NY: Oxford University Press. p. 588. ISBN 978-0-19-960563-7.
  8. ^ See Systematic element name
  9. ^ a b http://biosphere.biologydaily.com/biology/Unbipentium
  10. ^ http://nicedefinition.com/Definition/Word/unbipentium/unbipentium.aspx
  11. ^ "Unbipentium — definition, examples, related words and more at Wordnik".
  12. ^ Fricke, B.; Greiner, W.; Waber, J. T. (1971). "The continuation of the periodic table up to Z = 172. The chemistry of superheavy elements" (PDF). Theoretica Chimica Acta. 21 (3): 235–260. doi:10.1007/BF01172015. S2CID 117157377.
  13. ^ Nefedov, V.I.; Trzhaskovskaya, M.B.; Yarzhemskii, V.G. (2006). "Electronic Configurations and the Periodic Table for Superheavy Elements" (PDF). Doklady Physical Chemistry. 408 (2): 149–151. doi:10.1134/S0012501606060029. ISSN 0012-5016. S2CID 95738861.
  14. ^ 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.
  15. ^ Hoffman, Lee & Pershina 2006, p. 1724.
  16. ^ Marcillac, Pierre de; Noël Coron; Gérard Dambier; Jacques Leblanc; Jean-Pierre Moalic (April 2003). "Experimental detection of α-particles from the radioactive decay of natural bismuth". Nature. 422 (6934): 876–878. Bibcode:2003Natur.422..876D. doi:10.1038/nature01541. PMID 12712201. S2CID 4415582.
  17. ^ Considine, Glenn D.; Kulik, Peter H. (2002). Van Nostrand's scientific encyclopedia (9 ed.). Wiley-Interscience. ISBN 978-0-471-33230-5. OCLC 223349096.
  18. ^ Koura, H.; Chiba, S. (2013). "Single-Particle Levels of Spherical Nuclei in the Superheavy and Extremely Superheavy Mass Region". Journal of the Physical Society of Japan. 82 (1): 014201. Bibcode:2013JPSJ...82a4201K. doi:10.7566/JPSJ.82.014201.
  19. ^ Encyclopaedia Britannica : article « Magic Number », § « The magic numbers for nuclei ».
  20. ^ Article ([[Special:EditPage/{{{1}}}|edit]] | [[Talk:{{{1}}}|talk]] | [[Special:PageHistory/{{{1}}}|history]] | [[Special:ProtectPage/{{{1}}}|protect]] | [[Special:DeletePage/{{{1}}}|delete]] | [{{fullurl:Special:Whatlinkshere/{{{1}}}|limit=999}} links] | [{{fullurl:{{{1}}}|action=watch}} watch] | logs | views)
  21. ^ Article ([[Special:EditPage/{{{1}}}|edit]] | [[Talk:{{{1}}}|talk]] | [[Special:PageHistory/{{{1}}}|history]] | [[Special:ProtectPage/{{{1}}}|protect]] | [[Special:DeletePage/{{{1}}}|delete]] | [{{fullurl:Special:Whatlinkshere/{{{1}}}|limit=999}} links] | [{{fullurl:{{{1}}}|action=watch}} watch] | logs | views)
  22. ^ a b Seaborg (c. 2006). "transuranium element (chemical element)". Encyclopædia Britannica. Retrieved 2010-03-16.
  23. ^ Hofmann, Sigurd (2002). On Beyond Americium. Taylor & Francis. p. 105. ISBN 978-0-415-28496-7.

Extended periodic table[edit]

Retrieved from "https://en.wikipedia.org/w/index.php?title=User:Praseodymium-141/Unbipentium&oldid=1195499984"