Difference between revisions of "Actinium"

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|atomic-number = 89
 
|atomic-number = 89
 
|configuration = [Rn] 6d<sup>1</sup> 7s<sup>2</sup>
 
|configuration = [Rn] 6d<sup>1</sup> 7s<sup>2</sup>
−
|phys-ref = <ref name="G&E">{{Greenwood&Earnshaw1st|pages=1102–10}}.</ref>
+
|phys-ref = <ref name="K&M">{{citation | last1 = Kirby | first1 = H. W. | last2 = Morss | first2 = L. R. | contribution = Actinium | title = The Chemistry of the Actinide and Transactinide Elements | editor1-first = Lester R. | editor1-last = Morss | editor2-first = Norman M. | editor2-last = Edelstein | editor3-first = Jean | editor3-last = Fuger | edition = 3rd | year = 2006 | volume = 1 | publisher = Springer | location = Dordrecht, the Netherlands | chapter = 2 | pages = 18–51 | url = http://radchem.nevada.edu/classes/rdch710/files/actinium.pdf | doi = 10.1007/1-4020-3598-5_2}}.</ref><ref group="note" name="est">Many of the properties of actinium are only known through estimation and/or extrapolation. Several estimates of the melting point and thermodynamic properties have been made; the boiling point was estimated on the basis of vapour pressure measurements; the electronegativity was estimated on the basis of periodic trends. The density and ionic radii were directly determined.</ref>
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|melting-point = 817&nbsp;°C (1090&nbsp;K)
+
|melting-point = 1050&nbsp;°C (1350&nbsp;K)
−
|boiling-point = 2470&nbsp;°C (2743&nbsp;K)
+
|boiling-point = 3300&nbsp;°C (3600&nbsp;K)
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|density =  
+
|density = 10.07 g cm<sup>−3</sup>
 
|resistivity =  
 
|resistivity =  
−
|chem-ref =  
+
|chem-ref = <ref>{{Pauling3rd}}.</ref><ref group="note" name="est"/>
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|electronegativity =  
+
|electronegativity = 1.3 (Pauling)
 
|IE-ref = <ref>{{citation | last = Sugar | first = Jack | title = Ionization energies of the neutral actinides | journal = J. Chem. Phys. | year = 1973 | volume = 59 | pages = 788–91 | doi = 10.1063/1.1680091}}. {{citation | last = Sugar | first = Jack | title = Revised ionization energies of the neutral actinides | journal = J. Chem. Phys. | year = 1974 | volume = 60 | page = 4103 | doi = 10.1063/1.1680874}}.</ref><ref>{{NSRDS-NBS 34}}.</ref>
 
|IE-ref = <ref>{{citation | last = Sugar | first = Jack | title = Ionization energies of the neutral actinides | journal = J. Chem. Phys. | year = 1973 | volume = 59 | pages = 788–91 | doi = 10.1063/1.1680091}}. {{citation | last = Sugar | first = Jack | title = Revised ionization energies of the neutral actinides | journal = J. Chem. Phys. | year = 1974 | volume = 60 | page = 4103 | doi = 10.1063/1.1680874}}.</ref><ref>{{NSRDS-NBS 34}}.</ref>
 
|IE1 = 5.17(12) eV<br/>499(12) kJ mol<sup>−1</sup>
 
|IE1 = 5.17(12) eV<br/>499(12) kJ mol<sup>−1</sup>
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|EA-ref =  
 
|EA-ref =  
 
|EA1 =  
 
|EA1 =  
−
|thermo-ref = <ref name="G&E"/>
+
|thermo-ref = <ref name="K&M"/><ref name="G&E">{{Greenwood&Earnshaw1st|pages=1102–10}}.</ref>
 
|entropy =  
 
|entropy =  
 
|enthalpy-vaporization = 293 kJ mol<sup>−1</sup>
 
|enthalpy-vaporization = 293 kJ mol<sup>−1</sup>
−
|enthalpy-atomization =  
+
|enthalpy-atomization = 406 kJ mol<sup>−1</sup>
 
|entropy-atomization =  
 
|entropy-atomization =  
 
|enthalpy-fusion = 10.5 kJ mol<sup>−1</sup>
 
|enthalpy-fusion = 10.5 kJ mol<sup>−1</sup>
 
|radius-ref = <ref>{{Cordero et al. (2008)}}.</ref><ref>{{Shannon (1976)}}.</ref>
 
|radius-ref = <ref>{{Cordero et al. (2008)}}.</ref><ref>{{Shannon (1976)}}.</ref>
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|metallic-radius =  
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|metallic-radius = 188 pm
 
|covalent-radius = 215 pm
 
|covalent-radius = 215 pm
 
|ionic-radius = 126 pm (Ac<sup>3+</sup>, ''O<sub>h</sub>'')
 
|ionic-radius = 126 pm (Ac<sup>3+</sup>, ''O<sub>h</sub>'')
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===References===
 
===References===
 
{{reflist}}
 
{{reflist}}
−
 
−
===Further reading===
 
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*{{citation | last1 = Kirby | first1 = H. W. | last2 = Morss | first2 = L. R. | contribution = Actinium | title = The Chemistry of the Actinide and Transactinide Elements | editor1-first = Lester R. | editor1-last = Morss | editor2-first = Norman M. | editor2-last = Edelstein | editor3-first = Jean | editor3-last = Fuger | edition = 3rd | year = 2006 | volume = 1 | publisher = Springer | location = Dordrecht, the Netherlands | chapter = 2 | pages = 18–51 | url = http://radchem.nevada.edu/classes/rdch710/files/actinium.pdf | doi = 10.1007/1-4020-3598-5_2}}.
 
  
 
==External links==
 
==External links==

Revision as of 17:35, 3 April 2011

radium ← actinium → thorium
La
↑
Ac
↓
—
Atomic properties
Atomic number 89
Electron configuration [Rn] 6d1 7s2
Physical properties[1][note 1]
Melting point 1050 °C (1350 K)
Boiling point 3300 °C (3600 K)
Density 10.07 g cm−3
Chemical properties[2][note 1]
Electronegativity 1.3 (Pauling)
Ionization energies[3][4]
1st 5.17(12) eV
499(12) kJ mol−1
2nd 12.06 eV
1164 kJ mol−1
Atomic radii[5][6]
Covalent radius 215 pm
Metallic radius 188 pm
Ionic radius 126 pm (Ac3+, Oh)
Thermodynamic properties[1][7]
Enthalpy change of atomization 406 kJ mol−1
Enthalpy change of fusion 10.5 kJ mol−1
Enthalpy change of vaporization 293 kJ mol−1
Miscellaneous
CAS number 7440-34-8
Where appropriate, and unless otherwise stated, data are given for 100 kPa (1 bar) and 298.15 K (25 °C).
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Actinium (symbol: Ac) is a chemical element, one of the transition metals and also an actinoid. All isotopes of actinium are unstable, with half-lives of less than 22 years:[8] however, actinium-227 (t½ = 21.772(3) a) is formed as a decay product of uranium-235 (t½ = 704(1) × 106 a) and so small amounts of actinium are present in all samples of natural uranium.

Notes and references

Notes

  1. ↑ 1.0 1.1 Many of the properties of actinium are only known through estimation and/or extrapolation. Several estimates of the melting point and thermodynamic properties have been made; the boiling point was estimated on the basis of vapour pressure measurements; the electronegativity was estimated on the basis of periodic trends. The density and ionic radii were directly determined.

References

  1. ↑ 1.0 1.1 Kirby, H. W.; Morss, L. R. Actinium. 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. 1, Chapter 2, pp 18–51. doi:10.1007/1-4020-3598-5_2, <http://radchem.nevada.edu/classes/rdch710/files/actinium.pdf>.
  2. ↑ Pauling, Linus The Nature of the Chemical Bond, 3rd ed.; Ithaca, NY, 1960. ISBN 0-8014-0333-2.
  3. ↑ Sugar, Jack Ionization energies of the neutral actinides. J. Chem. Phys. 1973, 59, 788–91. DOI: 10.1063/1.1680091. Sugar, Jack Revised ionization energies of the neutral actinides. J. Chem. Phys. 1974, 60, 4103. DOI: 10.1063/1.1680874.
  4. ↑ Moore, Charlotte E. Ionization potentials and ionization limits derived from the analyses of optical spectra. Natl. Stand. Ref. Data Ser., (U.S. Natl. Bur. Stand.) 1970, 34, 1–22, <http://www.nist.gov/data/nsrds/NSRDS-NBS34.pdf>.
  5. ↑ 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.
  6. ↑ 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.
  7. ↑ Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 1102–10. ISBN 0-08-022057-6.
  8. ↑ Audi, G.; Bersillon, O.; Blachot, J.; Wapstra, A. H. The NUBASE evaluation of nuclear and decay properties. Nucl. Phys. A 2003, 729, 3–128. doi:10.1016/j.nuclphysa.2003.11.001, <http://amdc.in2p3.fr/nubase/Nubase2003.pdf>.

External links

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