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Roentgenium

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Roentgenium, 111Rg
Roentgenium
Pronunciation
Mass number[282] (unconfirmed: 286)
Roentgenium 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
Au
↑
Rg
↓
—
darmstadtium ← roentgenium → copernicium
Atomic number (Z)111
Groupgroup 11
Periodperiod 7
Block  d-block
Electron configuration[Rn] 5f14 6d9 7s2 (predicted)[1][2]
Electrons per shell2, 8, 18, 32, 32, 17, 2 (predicted)
Physical properties
Phase at STPsolid (predicted)[3]
Density (near r.t.)22–24 g/cm3 (predicted)[4][5]
Atomic properties
Oxidation states(−1), (+1), (+3), (+5), (+7) (predicted)[2][6][7]
Ionization energies
  • 1st: 1020 kJ/mol
  • 2nd: 2070 kJ/mol
  • 3rd: 3080 kJ/mol
  • (more) (all estimated)[2]
Atomic radiusempirical: 138 pm (predicted)[2][6]
Covalent radius121 pm (estimated)[8]
Other properties
Natural occurrencesynthetic
Crystal structure ​body-centered cubic (bcc)
Body-centered cubic crystal structure for roentgenium

(predicted)[3]
CAS Number54386-24-2
History
Namingafter Wilhelm Röntgen
DiscoveryGesellschaft für Schwerionenforschung (1994)
Isotopes of roentgenium
Main isotopes[9] Decay
abun­dance half-life (t1/2) mode pro­duct
279Rg synth 0.09 s[10] α87% 275Mt
SF13% –
280Rg synth 3.9 s α 276Mt
281Rg synth 11 s[11] SF86% –
α14% 277Mt
282Rg synth 130 s α 278Mt
283Rg synth 5.1 min?[12] SF –
286Rg synth 10.7 min?[13] α 282Mt
 Category: Roentgenium
| references

Roentgenium (Template:PronEng, /rʌntˈdʒɛniəm/[14]) is a chemical element in the periodic table that has the symbol Rg and atomic number 111.

Roentgenium
Common English pronunciation of roentgenium
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It is a synthetic element whose most stable known isotope has a mass of 283 and an estimated half-life of ten minutes.

Official discovery

Element 111 was officially discovered by Peter Armbruster, Gottfried Münzenberg, and their team working at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany on December 8, 1994.[15] Only three atoms of it were observed (all 272Rg), by the cold fusion between 64Ni ions and a 209Bi target in a linear accelerator:

209
83Bi + 64
28Ni → 272
111Rg + 1
0n

In 2001, the IUPAC/IUPAP Joint Working Party (JWP) from concluded that there was insufficient evidence for the discovery at that moment in time.[16] The GSI team repeated their experiment in 2000 and detected a further 3 atoms.[17][18] In their 2003 report, the JWP decided that the GSI team should be acknowledged as the discoverers. [19]

Proposed name

The name roentgenium (Rg) was proposed by the GSI team[20] and was accepted as a permanent name on November 1 2004 in honor of the German physicist Wilhelm Conrad Röntgen.[21] Previously the element was known under the temporary IUPAC systematic element name unununium (Template:PronEng or /ˌʌnəˈnʌniəm/[22]), Uuu. Some research has referred to it as eka-gold.


Electronic structure

Non-relativistic

Roentgenium has 6 full shells, 7s+5p+3d+2f=17 full subshells, and 111 orbitals:

Bohr model: 2, 8, 18, 32, 32, 18, 1

Quantum mechanical model: 1s22s22p63s23p64s23d10 4p65s24d105p66s24f145d10 6p67s15f146d10

Relativistic

The stable group 11 elements, copper, silver, and gold all have an outer electron configuration nd10(n+1)s1. For each of these elements, their first excited state has a configuration nd9(n+1)s2. Due to spin-orbit coupling between the s electrons, this state is split into a pair of energy levels. For copper, the difference in energy between the ground state and lowest excited state causes the metal to appear reddish. For silver, the energy gap widens and it become silvery. However, as Z increases, the excited levels are stabilised by relativistic effects and in gold the energy gap decreases again and it appears gold. For roentgenium, calculations indicate that the 6d97s2 level is stabilised to such an extent that it becomes the ground state. The resulting energy difference between the new ground state and the first excited state is similar to that of silver and roentgenium is expected to be silvery in appearance.[23]

Extrapolated chemical properties of eka-gold

Oxidation states

Element 111 is projected to be the ninth member of the 6d series of transition metals and the heaviest member of group 11 (IB) in the Periodic Table, below copper, silver, and gold. Each of the members of this group show different stable states. Copper forms a stable +II state, whilst silver is predominantly found as Ag(I) and gold as Au(III). Copper(I) and silver(II) are also relatively well-known. Roentgenium is therefore expected to predominantly form a stable +III state.

Chemistry

The heavier members of this group are well known for their lack of reactivity or noble character. Silver and gold are both inert to oxygen. They are both however attacked by the halogens. In addition, silver is attacked by sulfur and hydrogen sulfide, highlighting its higher reactivity compared to gold. Roentgenium is expected to be even more noble than gold and can be expected to be inert to oxygen and halogens. The most-likely reaction is with fluorine to form a trifluoride, RgF3.

History of synthesis of isotopes by cold fusion

209Bi(64Ni,xn)273−xRg (x=1)

First experiments to synthesize element 111 were performed by the Dubna team in 1986 using this cold fusion reaction. No atoms were identified that could be assigned to atoms of element 111 and a production cross-section limit of 4 pb was determined. After an upgrade of their facilities, the team at GSI successfully detected 3 atoms of 272Rg in their discovery experiment.[15] A further 3 atoms were synthesized in 2000.[17] The discovery of roentgenium was confirmed in 2003 when a team at RIKEN measured the decays of 14 atoms of 272Rg during the measurement of the 1n excitation function.[24]

208Pb(65Cu,xn)273−xRg (x=1)

In 2004, as part of their study of odd-Z projectiles in cold fusion reactions, the team at LBNL detected a single atom of 272Rg in this new reaction.[25][26]

History of synthesis of isotopes as decay products

Isotopes of roentgenium have also been observed in the decay of heavier elements. Observations to date are outlined in the table below:

Evaporation residue Observed Rg isotope
288115 280Rg [27]
287115 279Rg [27]
282113 278Rg [28]
278113 274Rg [28]

Chronology of isotope discovery

Isotope Year discovered Discoverer reaction
272Rg 1994 209Bi(64Ni,n)
273Rg unknown
274Rg 2004 209Bi(70Zn,n) [28]
275Rg unknown
276Rg unknown
277Rg unknown
278Rg 2006 237Np(48Ca,3n) [28]
279Rg 2003 243Am(48Ca,4n) [27]
280Rg 2003 243Am(48Ca,3n) [27]

Chemical yields of isotopes

Cold fusion

The table below provides cross-sections and excitation energies for cold fusion reactions producing roentgenium isotopes directly. Data in bold represents maxima derived from excitation function measurements. + represents an observed exit channel.

Projectile Target CN 1n 2n 3n
64Ni 209Bi 3.5 pb, 12.5 MeV
65Cu 208Pb 273Rg 1.7 pb, 13.2 MeV

Isotopes

Five isotopes of roentgenium are known. The longest-lived of these is 280Rg, which decays through alpha decay and has a halflife of 3.6 seconds. The shortest-lived isotope is 272Rg, which decays through alpha decay and has a halflife of 1.6 ms.

Isomerism in roentgenium nuclides

274Rg

Two atoms of 274Rg have been observed in the decay chains starting with 278Uut. The two events occur with different energies and with different lifetimes. In addition, the two entire decay chains appear to be different. This suggests the presence of two isomeric levels but further research is required.

272Rg

The direct production of 272Rg has provided four alpha lines at 11.37, 11.03, 10.82, and 10.40 MeV. The GSI measured a half-life of 1.6 ms whilst recent data from RIKEN has given a half-life of 3.8 ms. The conflicting data may be due to isomeric levels but the current data are insufficient to come to any firm assignments.

Future experiments

To date there has been no attempt to synthesise roentgenium in hot fusion reactions. It has been mentioned by the Dubna team that they could complete their Ca-48 projectile program by studying the reaction

231
91Pa + 48
20Ca → 279
111Rg → 276, 275, 274
111Rg

References

  1. ^ Turler, A. (2004). "Gas Phase Chemistry of Superheavy Elements" (PDF). Journal of Nuclear and Radiochemical Sciences. 5 (2): R19–R25. doi:10.14494/jnrs2000.5.R19.
  2. ^ a b c d 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.
  3. ^ a b Östlin, A.; Vitos, L. (2011). "First-principles calculation of the structural stability of 6d transition metals". Physical Review B. 84 (11): 113104. Bibcode:2011PhRvB..84k3104O. doi:10.1103/PhysRevB.84.113104.
  4. ^ Gyanchandani, Jyoti; Sikka, S. K. (10 May 2011). "Physical properties of the 6 d -series elements from density functional theory: Close similarity to lighter transition metals". Physical Review B. 83 (17): 172101. Bibcode:2011PhRvB..83q2101G. doi:10.1103/PhysRevB.83.172101.
  5. ^ Kratz; Lieser (2013). Nuclear and Radiochemistry: Fundamentals and Applications (3rd ed.). p. 631.
  6. ^ a b 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.
  7. ^ Conradie, Jeanet; Ghosh, Abhik (15 June 2019). "Theoretical Search for the Highest Valence States of the Coinage Metals: Roentgenium Heptafluoride May Exist". Inorganic Chemistry. 2019 (58): 8735–8738. doi:10.1021/acs.inorgchem.9b01139. PMID 31203606. S2CID 189944098.
  8. ^ Chemical Data. Roentgenium - Rg, Royal Chemical Society
  9. ^ 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.
  10. ^ http://www.jinr.ru/posts/both-neutron-properties-and-new-results-at-she-factory/
  11. ^ Oganessian, Yuri Ts.; Abdullin, F. Sh.; Alexander, C.; Binder, J.; et al. (2013-05-30). "Experimental studies of the 249Bk + 48Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope 277Mt". Physical Review C. 87 (054621). American Physical Society. Bibcode:2013PhRvC..87e4621O. doi:10.1103/PhysRevC.87.054621.
  12. ^ Hofmann, S.; Heinz, S.; Mann, R.; et al. (2016). "Remarks on the Fission Barriers of SHN and Search for Element 120". In Peninozhkevich, Yu. E.; Sobolev, Yu. G. (eds.). Exotic Nuclei: EXON-2016 Proceedings of the International Symposium on Exotic Nuclei. Exotic Nuclei. pp. 155–164. doi:10.1142/9789813226548_0024. ISBN 9789813226555.
  13. ^ Hofmann, S.; Heinz, S.; Mann, R.; et al. (2016). "Review of even element super-heavy nuclei and search for element 120". The European Physics Journal A. 2016 (52): 180. Bibcode:2016EPJA...52..180H. doi:10.1140/epja/i2016-16180-4. S2CID 124362890.
  14. ^ Roentgenium - Definitions from Dictionary.com
  15. ^ a b "The new element 111", Hofmann et al., Z. Phys. A., 1995, 350, 4. Retrieved on 2008-03-02/
  16. ^ "ON THE DISCOVERY OF THE ELEMENTS 110–112", Karol et al., Pure Appl. Chem., Vol. 73, No. 6, pp. 959–967, 2001. Retrieved on 2008-03-02
  17. ^ a b "New results on elements 111 and 112", Hofmann et al., Eur. Phys. J. A., 2002, 14, 2. Retrieved on 2008-03-02/
  18. ^ "New results on element 111 and 112", Hofmann et al., GSI report 2000. Retrieved on 2008-03-02
  19. ^ "ON THE CLAIMS FOR DISCOVERY OF ELEMENTS 110, 111, 112, 114, 116, AND 118*", Karol et al., Pure Appl. Chem., Vol. 75, No. 10, pp. 1601–1611, 2003. Retrieved on 2008-03-02
  20. ^ "NAME AND SYMBOL OF THE ELEMENT WITH ATOMIC NUMBER 111", Corish et al., IUPAC Provisional Recommendations. Retrieved on 2008-03-02
  21. ^ "Name and symbol of the element with atomic number 111", Corish et al., Pure Appl. Chem., 2004, Vol. 76, No. 12, pp. 2101-2103. Retrieved on 2008-03-02
  22. ^ [1]
  23. ^ "Gas Phase Chemistry of Superheavy Elements", Turler, A., Journal of Nuclear and Radiochemical Sciences, Vol. 5, No.2, pp. R19-R25, 2004. Retrieved on 2008-03-03
  24. ^ "Status of heavy element research using GARIS at RIKEN", Morita et al., Nucl. Phys. A734, 101 (2004). Retrieved on 2008-03-03
  25. ^ "Development of an Odd-Z-Projectile Reaction for Heavy Element Synthesis: 208Pb(64Ni,n)271Ds and 208Pb(65Cu,n)272111", Folden et al., Phys. Rev. Lett., 93, 212702 (2004). Retrieved on 2008-03-02
  26. ^ "Development of an Odd-Z-Projectile Reaction for Heavy Element Synthesis: 208Pb(64Ni,n)271Ds and 208Pb(65Cu,n)272111", Folden et al., LBNL repositories. Retrieved on 2008-03-02
  27. ^ a b c d see ununpentium for details
  28. ^ a b c d see ununtrium for details

See also

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