Difference between revisions of "Berkelium"

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|radius-ref = <ref name="Peterson"/><ref>Shannon and Prewitt, 1969</ref><ref>{{Shannon (1976)}}.</ref>
 
|radius-ref = <ref name="Peterson"/><ref>Shannon and Prewitt, 1969</ref><ref>{{Shannon (1976)}}.</ref>
 
|metallic-radius = 170 pm
 
|metallic-radius = 170 pm
|ionic-radius = 96 pm (Bk<sup>3+</sup>, ''O<sub>h</sub>'')<br/>83 pm (Bk<sup>4+</sup>, ''O<sub>h</sub>'')
+
|ionic-radius = 96 pm (Bk<sup>3+</sup>, ''O<sub>h</sub>'')<ref group="Note" name="radius">The quoted atomic radii are based on the usual convention that ''r''(O<sup>2−</sub>, ''O<sub>h</sub>'')&nbsp;= 140&nbsp;pm; on the alternative convention of ''r''(F<sup>−</sub>, ''O<sub>h</sub>'')&nbsp;= 119&nbsp;pm, the value would be 110&nbsp;pm for octahedral Bk<sup>3+</sup>.</ref><br/>83 pm (Bk<sup>4+</sup>, ''O<sub>h</sub>'')
 
|thermo-ref = <ref name="Ward"/><ref>Ward and Hill, 1976</ref>
 
|thermo-ref = <ref name="Ward"/><ref>Ward and Hill, 1976</ref>
 
|entropy = 76.2(13) J K<sup>−1</sup> mol<sup>−1</sup>
 
|entropy = 76.2(13) J K<sup>−1</sup> mol<sup>−1</sup>

Revision as of 09:01, 26 September 2010

curiumberkeliumcalifornium
Tb

Bk

Atomic properties
Atomic number 97
Electron configuration [Rn] 5f9 7s2
Physical properties[1][2][3]
Melting point 1272(22) K (999(22) °C)[Note 1]
Boiling point 2900(50) K (2625(50) °C)
Density 14.78 g cm−3
Chemical properties[4]
Electronegativity 1.3 (Pauling)
Ionization energy[5][6]
6.1979(2) eV
598.01(2) kJ mol−1
Atomic radii[3][7][8]
Metallic radius 170 pm
Ionic radius 96 pm (Bk3+, Oh)[Note 2]
83 pm (Bk4+, Oh)
Thermodynamic properties[2][9]
Standard entropy 76.2(13) J K−1 mol−1
Enthalpy change of atomization 310(6) kJ mol−1
Enthalpy change of fusion 7.92 kJ mol−1
Miscellaneous
CAS number 7440-40-6
Where appropriate, and unless otherwise stated, data are given for 100 kPa (1 bar) and 298.15 K (25 °C).

Berkelium (symbol: Bk) is a synthetic chemical element and a member of the actinoid series. It is named after the city of Berkeley, California, the location of the University of California Radiation Laboratory where it was discovered in 1949.

Notes and references

Notes

  1. The melting point quoted here is the weighted mean of the values found by Fahey et al. (1972)[1] and Ward et al. (1982).[2]
  2. The quoted atomic radii are based on the usual convention that r(O2−, Oh) = 140 pm; on the alternative convention of r(F−, Oh) = 119 pm, the value would be 110 pm for octahedral Bk3+.

References

  1. 1.0 1.1 Fahey et al., 1972
  2. 2.0 2.1 2.2 Ward et al., 1982
  3. 3.0 3.1 Peterson et al., 1971
  4. Pauling, Linus The Nature of the Chemical Bond, 3rd ed.; Ithaca, NY, 1960. ISBN 0-8014-0333-2.
  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. Erdmann, N.; Nunnemann, M.; Eberhardt, K.; Herrmann, G.; Huber, G.; Köhler, S.; Kratz, J. V.; Passler, G., et al. Determination of the first ionization potential of nine actinide elements by resonance ionization mass spectroscopy (RIMS). J. Alloys Compd. 1998, 271–273, 837–40. DOI: 10.1016/S0925-8388(98)00229-1.
  7. Shannon and Prewitt, 1969
  8. 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.
  9. Ward and Hill, 1976

External links

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