Jump to content

Moscovium: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
[pending revision][pending revision]
← Previous editNext edit →
Content deleted Content added
VisualWikitext
Revert to revision 575590036 dated 2013-10-03 15:12:18 by Edgar181 using popups
Line 69: Line 69:


===Hot fusion===
===Hot fusion===
Hot fusion reactions are processes that create compound nuclei at high excitation energy (~40–50 MeV, hence "hot"), leading to a reduced probability of survival from fission. The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing <sup>48</sup>Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as "warm" fusion reactions. This leads, in part, to relatively high yields from these reactions.
Hot fusion reactions are processes that create compound nuclei at high excitation energy (~40–50 MeV, therefore "hot"), leading to a reduced probability of survival from fission. The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing <sup>48</sup>Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as "warm" fusion reactions. This leads, in part, to relatively high yields from these reactions.


;<sup>238</sup>U(<sup>51</sup>V,''x''n)<sup>289−''x''</sup>Uup
;<sup>238</sup>U(<sup>51</sup>V,''x''n)<sup>289−''x''</sup>Uup

Revision as of 14:03, 8 October 2013

"Uup" and "UUp" redirect here. For the political party, see Ulster Unionist Party.
"Element 115" redirects here. For fictional and conspiracy references to element 115, see Materials science in science fiction.
Moscovium, 115Mc
Moscovium
Pronunciation/mɒˈskoʊviəm/ ​(mos-SKOH-vee-əm)
Mass number[290] (data not decisive)[a]
Moscovium 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
Bi
↑
Mc
↓
—
flerovium ← moscovium → livermorium
Atomic number (Z)115
Groupgroup 15 (pnictogens)
Periodperiod 7
Block  p-block
Electron configuration[Rn] 5f14 6d10 7s2 7p3 (predicted)[3]
Electrons per shell2, 8, 18, 32, 32, 18, 5 (predicted)
Physical properties
Phase at STPsolid (predicted)[3]
Melting point670 K ​(400 °C, ​750 °F) (predicted)[3][4]
Boiling point~1400 K ​(~1100 °C, ​~2000 °F) (predicted)[3]
Density (near r.t.)13.5 g/cm3 (predicted)[4]
Heat of fusion5.90–5.98 kJ/mol (extrapolated)[5]
Heat of vaporization138 kJ/mol (predicted)[4]
Atomic properties
Oxidation states(+1), (+3) (predicted)[3][4]
Ionization energies
  • 1st: 538.3 kJ/mol (predicted)[6]
  • 2nd: 1760 kJ/mol (predicted)[4]
  • 3rd: 2650 kJ/mol (predicted)[4]
  • (more)
Atomic radiusempirical: 187 pm (predicted)[3][4]
Covalent radius156–158 pm (extrapolated)[5]
Other properties
Natural occurrencesynthetic
CAS Number54085-64-2
History
NamingAfter Moscow region
DiscoveryJoint Institute for Nuclear Research and Lawrence Livermore National Laboratory (2003)
Isotopes of moscovium
Main isotopes Decay
abun­dance half-life (t1/2) mode pro­duct
286Mc synth 20 ms[7] α 282Nh
287Mc synth 38 ms α 283Nh
288Mc synth 193 ms α 284Nh
289Mc synth 250 ms[8][9] α 285Nh
290Mc synth 650 ms[8][9] α 286Nh
 Category: Moscovium
| references
Ununpentium
Common English pronunciation of ununpentium
Problems playing this file? See media help.

Ununpentium is the temporary name of a synthetic superheavy element in the periodic table that has the temporary symbol Uup and has the atomic number 115.

It is placed as a heavier homologue to bismuth and the heaviest member of group 15 (VA). It was first observed in 2003 and about 50 atoms of ununpentium have been synthesized to date, with about 25 direct decays of the parent element having been detected. Four consecutive isotopes are currently known, 287–290Uup, with 289Uup having the longest measured half-life of ~200 ms.[10] On August 27, 2013, researchers at GSI from Lund University in Sweden reported confirming the existence of the element.[11][12] On September 10, 2013, researchers from the same research group working in Darmstadt, Germany reported synthesis as well. [13]

History

Discovery profile

Simulation of an accelerated calcium-48 ion about to collide with an americium-243 target atom.

On February 2, 2004, synthesis of ununpentium was reported in Physical Review C by a team composed of Russian scientists at the Joint Institute for Nuclear Research in Dubna, and American scientists at the Lawrence Livermore National Laboratory.[14][15] The team reported that they bombarded americium-243 with calcium-48 ions to produce four atoms of ununpentium. These atoms, they report, decayed by emission of alpha-particles to ununtrium in approximately 100 milliseconds.

48
20Ca
 + 243
95Am
 → The element ununpentium does not exist.*
 → The element ununpentium does not exist. + 3 n → The element ununtrium does not exist. + α

The Dubna–Livermore collaboration has strengthened their claim for the discovery of ununpentium by conducting chemical experiments on the decay daughter 268Db. In experiments in June 2004 and December 2005, the dubnium isotope was successfully identified by milking the Db fraction and measuring any SF activities.[16][17] Both the half-life and decay mode were confirmed for the proposed 268Db which lends support to the assignment of Z=115 to the parent nuclei.

Sergei Dmitriev from the Flerov Laboratory of Nuclear Reactions (FLNR) in Dubna, Russia, has formally put forward their claim of discovery of ununpentium to the IUPAC/IUPAP Joint Working Party (JWP).[18] In 2011, the IUPAC evaluated the Dubna–Livermore results and concluded that they did not meet the criteria for discovery.[19]

Naming

Ununpentium is historically known as eka-bismuth. Ununpentium is a temporary IUPAC systematic element name derived from the digits 115, where "un-" represents Latin unum. "Pent-" represents the Greek word for 5, and it was chosen because the Latin word for 5 ("quin")[20] starts with 'q', which would have caused confusion with flerovium (previously known as ununquadium), element 114. Research scientists usually refer to the element simply as element 115.[21]

Current and future experiments

The team at Dubna are currently running another series of experiments on the 243Am(48Ca,xn) reaction. They are attempting to complete the 4n excitation function and confirm the data for 287Uup. They are also hoping to identify some decays from the 2n and 5n exit channels. This reaction will run until the Christmas shutdown.

The FLNR also have future plans to study light isotopes of element 115 using the reaction 241Am + 48Ca.[22]

A team of researchers at Lund University announced they had corroborated the 2004 findings in August 2013 by shooting calcium ions into a thin film of americium.[23][24] Researchers at the GSI Helmholtz in Darmstadt, Germany reported discovery of ununpentium using the same reaction just two weeks later, on September 10, 2013.[13]

Nucleosynthesis

Target-projectile combinations

The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with Z=115. Each entry is a combination for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.

Target Projectile CN Attempt result
208Pb 75As 283Uup Reaction yet to be attempted
232Th 55Mn 287Uup Reaction yet to be attempted
238U 51V 289Uup Failure to date
237Np 50Ti 287Uup Reaction yet to be attempted
244Pu 45Sc 289Uup Reaction yet to be attempted
243Am 48Ca 291Uup[25][26] Successful reaction
241Am 48Ca 289Uup Planned Reaction
248Cm 41K 289Uup Reaction yet to be attempted
249Bk 40Ar 289Uup Reaction yet to be attempted
249Cf 37Cl 286Uup Reaction yet to be attempted

Hot fusion

Hot fusion reactions are processes that create compound nuclei at high excitation energy (~40–50 MeV, therefore "hot"), leading to a reduced probability of survival from fission. The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing 48Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as "warm" fusion reactions. This leads, in part, to relatively high yields from these reactions.

238U(51V,xn)289−xUup

There are strong indications that this reaction was performed in late 2004 as part of a uranium(IV) fluoride target test at the GSI. No reports have been published, suggesting that no product atoms were detected, as anticipated by the team.[27]

243Am(48Ca,xn)291−xUup (x=2,3,4)

This reaction was first performed by the team in Dubna in July–August 2003. In two separate runs, they were able to detect 3 atoms of 288Uup and a single atom of 287Uup. The reaction was studied further in June 2004 in an attempt to isolate the descendant 268Db from the 288Uup decay chain. After chemical separation of a +4/+5 fraction, 15 SF decays were measured with a lifetime consistent with 268Db. In order to prove that the decays were from dubnium-268, the team repeated the reaction in August 2005 and separated the +4 and +5 fractions and further separated the +5 fractions into tantalum-like and niobium-like ones. Five SF activities were observed, all occurring in the +5 fractions and none in the tantalum-like fractions, proving that the product was indeed isotopes of dubnium.

In a series of experiments between October 2010 – February 2011, scientists at the FLNR studied this reaction at a range of excitation energies. They were able to detect 21 atoms of 288Uup and one atom of 289Uup, from the 2n exit channel. This latter result was used to support the synthesis of ununseptium. The 3n excitation function was completed with a maximum at ~8 pb. The data was consistent with that found in the first experiments in 2003.

Isotopes and nuclear properties

Chronology of isotope discovery
Isotope Year discovered Discovery reaction
287Uup 2003 243Am(48Ca,4n)
288Uup 2003 243Am(48Ca,3n)
289Uup 2009 249Bk(48Ca,4n)[10]
290Uup 2009 249Bk(48Ca,3n)[10]

Chemical properties

Extrapolated chemical properties

Oxidation states

Ununpentium is projected to be the third member of the 7p series of chemical elements and the heaviest member of group 15 (VA) in the Periodic Table, below bismuth. In this group, each member is known to portray the group oxidation state of +V but with differing stability. For nitrogen, the +V state is very difficult to achieve due to the lack of low-lying d-orbitals and the inability of the small nitrogen atom to accommodate five ligands. The +V state is well represented for phosphorus, arsenic, and antimony. However, for bismuth it is rare due to the reluctance of the 6s2 electrons to participate in bonding. This effect is known as the "inert pair effect" and is commonly linked to relativistic stabilisation of the 6s-orbitals. It is expected that ununpentium will continue this trend and portray only +III and +I oxidation states. Nitrogen(I) and bismuth(I) are known but rare and ununpentium(I) is likely to show some unique properties.[28] Because of spin-orbit coupling, flerovium may display closed-shell or noble gas-like properties; if this is the case, ununpentium will likely be monovalent as a result, since the cation Uup+ will have the same electron configuration as flerovium.

Chemistry

Ununpentium should display eka-bismuth chemical properties and should therefore form a sesquioxide, Uup2O3, and analogous chalcogenides, Uup2S3, Uup2Se3 and Uup2Te3. It should also form trihydrides and trihalides, i.e. UupH3, UupF3, UupCl3, UupBr3 and UupI3. If the +V state is accessible, it is likely that it is only possible in the fluoride, UupF5.[29][failed verification]

Stability

Main article: Island of stability

All the reported above isotopes of element 115, obtained by nuclear collisions of lighter nuclei, are severely neutron-deficient, because the proportion of neutrons to protons needed for maximum stability increases with atomic number. The most stable isotope will probably be 299Uup, with 184 neutrons, a known "magic" closed-shell number conferring exceptional stability, making it (with one further proton outside the "magic number" of 114 protons) both the chemical and the nuclear homolog of 209Bi; but the technology required to add the required neutrons presently does not exist. This is because no known combination of target and projectile can result in the required neutrons. It has been suggested[by whom?] that such a neutron-rich isotope could be formed by quasifission (fusion followed by fission) of a massive nucleus, multi-nucleon transfer reactions in collisions of actinide nuclei, or by the alpha decay of a massive nucleus (although this would depend on the stability of the parent nuclei towards spontaneous fission).

References

  1. ^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
  2. ^ Oganessian, Yu. Ts.; Utyonkov, V. K.; Kovrizhnykh, N. D.; et al. (2022). "New isotope 286Mc produced in the 243Am+48Ca reaction". Physical Review C. 106 (64306): 064306. Bibcode:2022PhRvC.106f4306O. doi:10.1103/PhysRevC.106.064306. S2CID 254435744.
  3. ^ a b c d e f 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.
  4. ^ a b c d e f g Fricke, Burkhard (1975). "Superheavy elements: a prediction of their chemical and physical properties". Recent Impact of Physics on Inorganic Chemistry. Structure and Bonding. 21: 89–144. doi:10.1007/BFb0116498. ISBN 978-3-540-07109-9. Retrieved 4 October 2013.
  5. ^ a b Bonchev, Danail; Kamenska, Verginia (1981). "Predicting the Properties of the 113–120 Transactinide Elements". Journal of Physical Chemistry. 85 (9). American Chemical Society: 1177–1186. doi:10.1021/j150609a021.
  6. ^ 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.
  7. ^ Kovrizhnykh, N. (27 January 2022). "Update on the experiments at the SHE Factory". Flerov Laboratory of Nuclear Reactions. Retrieved 28 February 2022.
  8. ^ a b Oganessian, Yuri Ts.; Abdullin, F. Sh.; Bailey, P. D.; et al. (2010-04-09). "Synthesis of a New Element with Atomic Number Z=117". Physical Review Letters. 104 (142502). American Physical Society: 142502. Bibcode:2010PhRvL.104n2502O. doi:10.1103/PhysRevLett.104.142502. PMID 20481935.
  9. ^ a b Oganessian, Y.T. (2015). "Super-heavy element research". Reports on Progress in Physics. 78 (3): 036301. Bibcode:2015RPPh...78c6301O. doi:10.1088/0034-4885/78/3/036301. PMID 25746203. S2CID 37779526.
  10. ^ a b c Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1103/PhysRevLett.104.142502, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1103/PhysRevLett.104.142502 instead.
  11. ^ "Existence of new element confirmed". Lund University. 27 August 2013. Retrieved 27 August 2013.
  12. ^ Staff (27 August 2013). "Scientists say existence of new element confirmed". Associated Press. Retrieved 27 August 2013.
  13. ^ a b "Phys. Rev. Lett. 111, 112502 (2013): Spectroscopy of Element 115 Decay Chains". Prl.aps.org. Retrieved 2013-09-28.
  14. ^ Oganessian, Yu. Ts.; Utyonkoy, V. K.; Lobanov, Yu. V.; et al. (2004). "Experiments on the synthesis of element 115 in the reaction 243Am(48Ca,xn)291−x115". Physical Review C. 69 (2): 021601. Bibcode:2004PhRvC..69b1601O. doi:10.1103/PhysRevC.69.021601.
  15. ^ Oganessian; et al. (2003). "Experiments on the synthesis of element 115 in the reaction 243Am(48Ca,xn)291−x115" (PDF). JINR preprints. {{cite journal}}: Explicit use of et al. in: |author= (help)
  16. ^ Dmitriev, S. N.; Utyonkov, V. K.; Shishkin, S. V.; et al. (2005). "Results of the Experiment for Chemical Identification of Db as a Decay Product of Element 115". In Penionzhkevich, Yu. E.; Cherepanov, E. A. (eds.). International Symposium on Exotic Nuclei: Peterhof, Russia, July 5-12, 2004 (PDF). Hackensack: World Scientific. pp. 285–294. Bibcode:2005exnu.conf..285D. doi:10.1142/9789812701749_0040. ISBN 9789812701749. OCLC 77501503. {{cite book}}: |first2= missing |last2= (help)
  17. ^ Oganessian, Yu. Ts.; Utyonkov, V.; Dmitriev, S.; Lobanov, Yu.; Itkis, M.; Polyakov, A.; Tsyganov, Yu.; Mezentsev, A.; Yeremin, A. (2005). "Synthesis of elements 115 and 113 in the reaction 243Am+48Ca". Physical Review C. 72 (3): 034611. Bibcode:2005PhRvC..72c4611O. doi:10.1103/PhysRevC.72.034611. {{cite journal}}: Unknown parameter |displayauthors= ignored (|display-authors= suggested) (help)
  18. ^ "Project: Priority claims for the discovery of elements with atomic number greater than 111". IUPAC. Retrieved 2009-07-07.
  19. ^ Barber, Robert C.; Karol, Paul J.; Nakahara, Hiromichi; Vardaci, Emanuele; Vogt, Erich W. (2011). "Discovery of the elements with atomic numbers greater than or equal to 113 (IUPAC Technical Report)". Pure and Applied Chemistry. 83 (7): 1. doi:10.1351/PAC-REP-10-05-01.
  20. ^ Lewis, Charlton T. and Short, Charles. "quīni at A Latin Dictionary". Department of the Classics, Tufts University. Retrieved 2011-05-14.{{cite web}}: CS1 maint: multiple names: authors list (link)
  21. ^ Folden, Cody (31 January 2009). "The Heaviest Elements in the Universe" (PDF). Saturday Morning Physics at Texas A&M. Retrieved 9 March 2012.
  22. ^ "Study of heavy and superheavy nuclei (see experiment 1.5)". Flerov Laboratory of Nuclear Reactions.
  23. ^ "EXISTENCE OF NEW ELEMENT CONFIRMED". Lund University. 27 August 2013. Retrieved 27 August 2013.
  24. ^ "Spectroscopy of element 115 decay chains (Accepted for publication on Physical Review Letters on 9 August 2013)". Retrieved 2 September 2013.
  25. ^ Zagrebaev, V (2004). "Fusion-fission dynamics of super-heavy element formation and decay" (PDF). Nuclear Physics A. 734: 164. Bibcode:2004NuPhA.734..164Z. doi:10.1016/j.nuclphysa.2004.01.025.
  26. ^ Feng, Z; Jin, G; Li, J; Scheid, W (2009). "Production of heavy and superheavy nuclei in massive fusion reactions". Nuclear Physics A. 816: 33. arXiv:0803.1117. Bibcode:2009NuPhA.816...33F. doi:10.1016/j.nuclphysa.2008.11.003.
  27. ^ "List of experiments 2000–2006". Univerzita Komenského v Bratislave. Archived from the original on 2007-07-23.
  28. ^ Keller, O. L., Jr. (1974). "Predicted properties of the superheavy elements. III. Element 115, Eka-bismuth". Journal of Physical Chemistry. 78 (19): 1945. doi:10.1021/j100612a015. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)CS1 maint: multiple names: authors list (link)
  29. ^ WebElements – Bismuth Compounds


Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).

Retrieved from "https://en.wikipedia.org/w/index.php?title=Moscovium&oldid=576290681"