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=" | + | |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> |
− | |melting-point = | + | |melting-point = 1050 °C (1350 K) |
− | |boiling-point = | + | |boiling-point = 3300 °C (3600 K) |
− | |density = | + | |density = 10.07 g cm<sup>−3</sup> |
|resistivity = | |resistivity = | ||
− | |chem-ref = | + | |chem-ref = <ref>{{Pauling3rd}}.</ref><ref group="note" name="est"/> |
− | |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> | ||
− | |metallic-radius = | + | |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}} | ||
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==External links== | ==External links== |
Revision as of 18:35, 3 April 2011
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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
- ↑ 1.0 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
- ↑ 1.0 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>.
- ↑ Pauling, Linus The Nature of the Chemical Bond, 3rd ed.; Ithaca, NY, 1960. ISBN 0-8014-0333-2.
- ↑ 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.
- ↑ 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>.
- ↑ 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.
- ↑ 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.
- ↑ Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 1102–10. ISBN 0-08-022057-6.
- ↑ 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
See also the corresponding article on Wikipedia. |
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