Plutonium

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neptuniumplutoniumamericium
Sm

Pu

Atomic properties
Atomic number 94
Electron configuration [Rn] 5f6 7s2
Physical properties[1][2][3]
Melting point 640 °C (913 K)
Boiling point 3230 °C (3500 K)
Density 19.86 g cm−3
Electric resistivity 146 × 10−6 Ω cm
Chemical properties[4]
Electronegativity 1.28 (Pauling)
Ionization energy[5]
6.0258(2) eV,
581.40(2) kJ mol−1
Atomic radii[2][6][7]
Covalent radius 187 pm
Metallic radius 159 pm
Ionic radius 85 pm (Pu6+, Oh)
100 pm (Pu4+, Oh)
Thermodynamic properties[1][8]
Enthalpy change of fusion 2.73(10) kJ mol−1
Enthalpy change of vaporization 347.7(21) kJ mol−1
Molar heat capacity (Cp) 31.6 J K−1 mol−1
Miscellaneous
CAS number 7440-07-5
EC number 231-117-7
Where appropriate, and unless otherwise stated, data are given for 100 kPa (1 bar) and 298.15 K (25 °C).

Plutonium (symbol: Pu) is a chemical element, a member of the actinoid series. All isotopes of plutonium are unstable: trace amounts of the longest-lived isotope, plutonium-244 (t½ = 80.0(9) × 106 a) have been found in bastnasite ores,[9] and trace amounts of plutonium-239 (t½ = 24.11(3) × 103 a) are naturally formed by the capture of neutrons by uranium-238.[10][11] Apart from these traces, plutonium is prepared artificially in nuclear reactors: about 2000 tonnes has been prepared in this way.[12]

Plutonium was first prepared in 1940 by Glenn Seaborg and Edwin McMillan at the University of California Radiation Laboratory, by the deuteron bombardment of uranium-238.[13] It was named after the planet Pluto, by analogy with uranium, named after the planet Uranus, and neptunium, named after the planet Neptune.[14]

Notes and references

Notes

References

  1. 1.0 1.1 Clark, David L.; Hecker, Siegfried S.; Jarvinen, Gordon D.; Neu, Mary P. Plutonium. In The Chemistry of the Actinide and Transactinide Elements, 3rd ed.; Morss, Lester R.; Edelstein, Norman M.; Fuger, Jean, Eds.; Springer: Dordrecht, the Netherlands, 2006; Vol. 2, Chapter 7, pp 813–1264. doi:10.1007/1-4020-3598-5_7, <http://radchem.nevada.edu/classes/rdch710/files/plutonium.pdf>.
  2. 2.0 2.1 Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 1450–86. ISBN 0-08-022057-6.
  3. Electrical resistivities. In Kaye & Laby Tables of Physical & Chemical Constants, 16th ed., 1995; Chapter 2.6.1, <http://www.kayelaby.npl.co.uk/general_physics/2_6/2_6_1.html>. (accessed 4 April 2011).
  4. Allred, A. L. Electronegativity values from thermochemical data. J. Inorg. Nucl. Chem. 1961, 17 (3–4), 215–21. DOI: 10.1016/0022-1902(61)80142-5.
  5. Köhler, S.; Deißenberger, R.; Eberhardt, K.; Erdmann, N.; Herrmann, G.; Huber, G.; Kratz, J. V.; Nunnemann, M., et al. Determination of the first ionization potential of actinide elements by resonance ionization mass spectroscopy. Spectrochim. Acta, Part B 1997, 52 (6), 717–26. DOI: 10.1016/S0584-8547(96)01670-9.
  6. Cordero, Beatriz; Gómez, Verónica; Platero-Prats, Ana E.; Revés, Marc; Echeverría, Jorge; Cremades, Eduard; Barragán, Flavia; Alvarez, Santiago Covalent radii revisited. Dalton Trans. 2008 (5), 2832–38. DOI: 10.1039/b801115j.
  7. Shannon, R. D. Revised effective ionic radii and systematic studies of interatomic distances in halids and chalcogenides. Acta Crystallogr. A 1976, 32 (5), 751–67. DOI: 10.1107/S0567739476001551.
  8. Oetting, F. L.; Rand, M. H.; Ackerman, R. J. The Chemical Thermodynamics of Actinide Elements and Compounds; IAEA: Vienna, 1976; Vol. 1. ISBN 9201490763.
  9. Hoffman, D. C.; Lawrence, F. O.; Mewherter, J. L.; Rourke, F. M. Detection of Plutonium-244 in Nature. Nature 1971, 234, 132–34. DOI: 10.1038/234132a0.
  10. Seaborg, Glenn T.; Perlman, Morris L. Search for Elements 94 and 93 in Nature. Presence of 94239 in Pitchblende. J. Am. Chem. Soc. 1948, 70 (4), 1571–73. DOI: 10.1021/ja01184a083.
  11. Garner, C. S.; Bonner, N. A.; Seaborg, G. T. Search for Elements 94 and 93 in Nature. Presence of 94239 in Carnotite. J. Am. Chem. Soc. 1948, 70 (10), 3453–54. DOI: 10.1021/ja01190a069.
  12. Albright, David; Kramer, Kimberly Fissile Material: Stockpiles Still Growing. Bull. At. Sci. 2004, 60 (6), 14–16. DOI: 10.2968/060006005.
  13. Seaborg, G. T.; Wahl, A. C.; Kennedy, J. W. Radioactive Element 94 from Deuterons on Uranium. Phys. Rev. 1946, 69 (7–8), 367. DOI: 10.1103/PhysRev.69.367.
  14. Seaborg, Glenn T.; Wahl, Arthur C. The Chemical Properties of Elements 94 and 93. J. Am. Chem. Soc. 1948, 70 (3), 1128–34. DOI: 10.1021/ja01183a076.

Further reading

  • Lemire, R. J.; Fuger, J.; Nitsche, H.; Potter, P.; Rand, M. H.; Rydberg, J.; Spahiu, K.; Sullivan, J. C., et al. Chemical Thermodynamics of Neptunium and Plutonium; Elsevier: Amsterdam, 2001. ISBN 044450379X.

External links

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