Difference between revisions of "Thorium"

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|below = —
 
|below = —
 
|atomic-number = 90
 
|atomic-number = 90
 +
|atomic-weight = 232.038 06(2)
 
|configuration = [Rn] 6d<sup>2</sup> 7s<sup>2</sup>
 
|configuration = [Rn] 6d<sup>2</sup> 7s<sup>2</sup>
 
|phys-ref = <ref name="WFD">{{citation | last1 = Wickleder | first1 = Mathias S. | last2 = Fourest | first2 = Blandine | last3 = Dorhout | first3 = Peter K. | contribution = Thorium | 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 = 3 | pages = 52–160 | url = http://radchem.nevada.edu/classes/rdch710/files/thorium.pdf | doi = 10.1007/1-4020-3598-5_3}}.</ref><ref name="G&E">{{Greenwood&Earnshaw1st|pages=1450–86}}.</ref>
 
|phys-ref = <ref name="WFD">{{citation | last1 = Wickleder | first1 = Mathias S. | last2 = Fourest | first2 = Blandine | last3 = Dorhout | first3 = Peter K. | contribution = Thorium | 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 = 3 | pages = 52–160 | url = http://radchem.nevada.edu/classes/rdch710/files/thorium.pdf | doi = 10.1007/1-4020-3598-5_3}}.</ref><ref name="G&E">{{Greenwood&Earnshaw1st|pages=1450–86}}.</ref>
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|density = 11.72 g cm<sup>−3</sup>
 
|density = 11.72 g cm<sup>−3</sup>
 
|resistivity = 15.7{{e|−6}} Ω cm
 
|resistivity = 15.7{{e|−6}} Ω cm
−
|chem-ref =  
+
|chem-ref = <ref>{{Pauling3rd|pages=88–95}}.</ref>
−
|electronegativity =  
+
|electronegativity = 1.3 (Pauling)
−
|IE-ref = <ref>{{citation | last1 = Köhler | first1 = S. | last2 = Deißenberger | first2 = R. | last3 = Eberhardt | first3 = K. | last4 = Erdmann | first4 = N. | last5 = Herrmann | firat5 = G. | last6 = Huber | first6 = G. | last7 = Kratz | first7 = J. V. | last8 = Nunnemann | first8 = M. | last9 = Passler | first9 = G. | last10 = Rao | first10 = P. M. | last11 = Riegel | first11 = J. | last12 = Trautmann | first12 = N. | last13 = Wendt | first13 = K. | year = 1997 | title = Determination of the first ionization potential of actinide elements by resonance ionization mass spectroscopy  | journal = Spectrochim. Acta, Part B | volume = 52 | issue = 6 | pages = 717–26 | doi = 10.1016/S0584-8547(96)01670-9}}.</ref>
+
|IE-ref = <ref>{{citation | last1 = Köhler | first1 = S. | last2 = Deißenberger | first2 = R. | last3 = Eberhardt | first3 = K. | last4 = Erdmann | first4 = N. | last5 = Herrmann | firat5 = G. | last6 = Huber | first6 = G. | last7 = Kratz | first7 = J. V. | last8 = Nunnemann | first8 = M. | last9 = Passler | first9 = G. | last10 = Rao | first10 = P. M. | last11 = Riegel | first11 = J. | last12 = Trautmann | first12 = N. | last13 = Wendt | first13 = K. | year = 1997 | title = Determination of the first ionization potential of actinide elements by resonance ionization mass spectroscopy  | journal = Spectrochim. Acta, Part B | volume = 52 | issue = 6 | pages = 717–26 | doi = 10.1016/S0584-8547(96)01670-9}}.</ref><ref>{{Moore (1970)}}.</ref>
−
|IE1 = 6.3067(2) eV<br/>608.50(2) kJ mol<sup>−1</sup>
+
|IE1 = 6.3067(2) eV,<br/>608.50(2) kJ mol<sup>−1</sup>
−
|IE2 =  
+
|IE2 = 11.8 eV,<br/>1131 kJ mol<sup>−1</sup>
−
|IE3 =  
+
|IE3 = 20.0 eV,<br/>1916 kJ mol<sup>−1</sup>
 +
|IE4 = 28.75 eV,<br/>2760 kJ mol<sup>−1</sup>
 
|EA-ref =  
 
|EA-ref =  
 
|EA1 =  
 
|EA1 =  
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'''Thorium''' (symbol: '''Th''') is a member of the [[actinoid]] series of [[chemical element]]s. Although all [[isotope]]s of thorium are [[Radioactivity|unstable]], [[thorium-232]] has a sufficiently long [[half-life]] (14 billion years) that a substantial amount of primordial thorium has survived since the formation of the Solar System. The natural material is only very slightly radioactive, and thorium and its compounds have a number of commercial uses, although some precautions must be taken over its decay products.
 
'''Thorium''' (symbol: '''Th''') is a member of the [[actinoid]] series of [[chemical element]]s. Although all [[isotope]]s of thorium are [[Radioactivity|unstable]], [[thorium-232]] has a sufficiently long [[half-life]] (14 billion years) that a substantial amount of primordial thorium has survived since the formation of the Solar System. The natural material is only very slightly radioactive, and thorium and its compounds have a number of commercial uses, although some precautions must be taken over its decay products.
  
−
Thorium was identified as a new element in 1828, and named after Thor, the Norse god of strength. Its chemistry resembles that of [[zirconium]] and [[hafnium]], with a preponderance of the +4 [[oxidation state]], and [[periodic table]]s from before the Second World War often placed thorium as a [[transition metal]].
+
Thorium was identified as a new element in 1828, and named after Thor, the Norse god of strength. Its chemistry resembles that of [[zirconium]] and [[hafnium]], with a preponderance of the +4 [[oxidation state]], and [[periodic table]]s from before the Second World War often placed thorium as a [[transition metal]].<ref name="EB11">{{EB11 | article = Thorium | volume = 26 | pages = 878–79}}.</ref>
  
 
==Discovery and history==
 
==Discovery and history==
 
Thorium was first identified in a sample of a new mineral (now called [[thorite]]) from the island of Løvøy in Vestfold, Norway. The sample was collected by the Lutheran pastor and amateur mineralogist Hans Morten Thrane Esmark; unable to identify it, he sent it to Christiana (modern-day Oslo) where his father Jens Esmark was professor of mineralogy and geology at the university. When Esmark Sr. had no more success than his son, he passed the sample on to the reknowned Swedish chemist [[Jöns Jacob Berzelius]], who correctly ascertained that the mineral contained a new chemical element.<ref>{{citation | first = J. J. | last = Berzelius | authorlink = Jöns Jacob Berzelius | title = Ueber den Thorit, ein neues Mineral, und eine darin enthaltene neue Erde, die Thorerde | journal = Ann. Phys. Chem. | year = 1829 | volume = 91 | issue = 4 | pages = 633–34 | doi = 10.1002/andp.18290910412}}.</ref><ref>{{citation | last = Berzelius | first = J. J. | authorlink = Jöns Jacob Berzelius | year = 1829 | title = Undersökning af ett nytt mineral (Thorit), som innehåller en förut obekant jord | journal = K. Sven. Vetenskapsakad. Handl. | volume = 9 | pages = 1–30}}; {{citation | title = Untersuchung eines neuen Minerals und einer darin enthaltenen zuvor unbekannten Erde | journal = Ann. Phys. Chem. | year = 1829 | volume = 92 | issue = 7 | pages = 385–415 | doi = 10.1002/andp.18290920702}}.</ref>
 
Thorium was first identified in a sample of a new mineral (now called [[thorite]]) from the island of Løvøy in Vestfold, Norway. The sample was collected by the Lutheran pastor and amateur mineralogist Hans Morten Thrane Esmark; unable to identify it, he sent it to Christiana (modern-day Oslo) where his father Jens Esmark was professor of mineralogy and geology at the university. When Esmark Sr. had no more success than his son, he passed the sample on to the reknowned Swedish chemist [[Jöns Jacob Berzelius]], who correctly ascertained that the mineral contained a new chemical element.<ref>{{citation | first = J. J. | last = Berzelius | authorlink = Jöns Jacob Berzelius | title = Ueber den Thorit, ein neues Mineral, und eine darin enthaltene neue Erde, die Thorerde | journal = Ann. Phys. Chem. | year = 1829 | volume = 91 | issue = 4 | pages = 633–34 | doi = 10.1002/andp.18290910412}}.</ref><ref>{{citation | last = Berzelius | first = J. J. | authorlink = Jöns Jacob Berzelius | year = 1829 | title = Undersökning af ett nytt mineral (Thorit), som innehåller en förut obekant jord | journal = K. Sven. Vetenskapsakad. Handl. | volume = 9 | pages = 1–30}}; {{citation | title = Untersuchung eines neuen Minerals und einer darin enthaltenen zuvor unbekannten Erde | journal = Ann. Phys. Chem. | year = 1829 | volume = 92 | issue = 7 | pages = 385–415 | doi = 10.1002/andp.18290920702}}.</ref>
  
−
Thorium remained something of a curiosity until the invention of the incandescent gas mantle in 1885 by [[Carl Auer von Welsbach]].
+
Thorium remained something of a curiosity until the invention of the incandescent gas mantle in 1885 by [[Carl Auer von Welsbach]]. The cover of [[thorium dioxide]] (with 1% [[cerium dioxide]]) over and around the gas flame increased the light output tenfold through [[candoluminescence]], and led to a huge expansion of public lighting in the late nineteenth and early twentieth centuries.<ref>{{EB11 | first = Vivian Byam | last = Lewes | article = Lighting, Gas | volume = 16 | pages = 655–59}}.</ref>
  
 
==Occurance and extraction==
 
==Occurance and extraction==
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[[Category:Chemical elements]]
 
[[Category:Chemical elements]]
 
[[Category:Actinoids]]
 
[[Category:Actinoids]]
 +
 +
{{CC-BY-3.0}}

Latest revision as of 14:27, 14 April 2011

actinium ← thorium → protactinium
Ce
↑
Th
↓
—
Atomic properties
Atomic number 90
Standard atomic weight 232.038 06(2)
Electron configuration [Rn] 6d2 7s2
Physical properties[1][2]
Melting point 1750 °C (2023 K)
Boiling point 4850 °C (5123 K)
Density 11.72 g cm−3
Electric resistivity 15.7 × 10−6 Ω cm
Chemical properties[3]
Electronegativity 1.3 (Pauling)
Ionization energies[4][5]
1st 6.3067(2) eV,
608.50(2) kJ mol−1
2nd 11.8 eV,
1131 kJ mol−1
3rd 20.0 eV,
1916 kJ mol−1
4th 28.75 eV,
2760 kJ mol−1
Atomic radii[1][6][7]
Covalent radius 206 pm
Metallic radius 180 pm
Ionic radius 108 pm (Th4+, Oh)
Thermodynamic properties[1][8]
Standard entropy 51.8(5) J K−1 mol−1
Enthalpy change of fusion 14 kJ mol−1
Enthalpy change of vaporization 602(6) kJ mol−1
Miscellaneous
CAS number 7440-29-1
EC number 231-139-7
Where appropriate, and unless otherwise stated, data are given for 100 kPa (1 bar) and 298.15 K (25 °C).
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Thorium (symbol: Th) is a member of the actinoid series of chemical elements. Although all isotopes of thorium are unstable, thorium-232 has a sufficiently long half-life (14 billion years) that a substantial amount of primordial thorium has survived since the formation of the Solar System. The natural material is only very slightly radioactive, and thorium and its compounds have a number of commercial uses, although some precautions must be taken over its decay products.

Thorium was identified as a new element in 1828, and named after Thor, the Norse god of strength. Its chemistry resembles that of zirconium and hafnium, with a preponderance of the +4 oxidation state, and periodic tables from before the Second World War often placed thorium as a transition metal.[9]

Discovery and history

Thorium was first identified in a sample of a new mineral (now called thorite) from the island of Løvøy in Vestfold, Norway. The sample was collected by the Lutheran pastor and amateur mineralogist Hans Morten Thrane Esmark; unable to identify it, he sent it to Christiana (modern-day Oslo) where his father Jens Esmark was professor of mineralogy and geology at the university. When Esmark Sr. had no more success than his son, he passed the sample on to the reknowned Swedish chemist Jöns Jacob Berzelius, who correctly ascertained that the mineral contained a new chemical element.[10][11]

Thorium remained something of a curiosity until the invention of the incandescent gas mantle in 1885 by Carl Auer von Welsbach. The cover of thorium dioxide (with 1% cerium dioxide) over and around the gas flame increased the light output tenfold through candoluminescence, and led to a huge expansion of public lighting in the late nineteenth and early twentieth centuries.[12]

Occurance and extraction

Notes and references

Notes

References

  1. ↑ 1.0 1.1 1.2 Wickleder, Mathias S.; Fourest, Blandine; Dorhout, Peter K. Thorium. 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 3, pp 52–160. doi:10.1007/1-4020-3598-5_3, <http://radchem.nevada.edu/classes/rdch710/files/thorium.pdf>.
  2. ↑ Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 1450–86. ISBN 0-08-022057-6.
  3. ↑ Pauling, Linus The Nature of the Chemical Bond, 3rd ed.; Ithaca, NY, 1960; pp 88–95. ISBN 0-8014-0333-2.
  4. ↑ Köhler, S.; Deißenberger, R.; Eberhardt, K.; Erdmann, N.; Herrmann; 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.
  5. ↑ 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>.
  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. ↑ Thorium. In NIST Chemistry WebBook; National Institute for Standards and Technology, <http://webbook.nist.gov/cgi/inchi/InChI%3D1S/Th>. (accessed 10 January 2011).
  9. ↑ Thorium. In Encyclopædia Britannica, 11th ed.; University Press: Cambridge, 1911; Vol. 26, pp 878–79.
  10. ↑ Berzelius, J. J. Ueber den Thorit, ein neues Mineral, und eine darin enthaltene neue Erde, die Thorerde. Ann. Phys. Chem. 1829, 91 (4), 633–34. DOI: 10.1002/andp.18290910412.
  11. ↑ Berzelius, J. J. Undersökning af ett nytt mineral (Thorit), som innehåller en förut obekant jord. K. Sven. Vetenskapsakad. Handl. 1829, 9, 1–30; Untersuchung eines neuen Minerals und einer darin enthaltenen zuvor unbekannten Erde. Ann. Phys. Chem. 1829, 92 (7), 385–415. DOI: 10.1002/andp.18290920702.
  12. ↑ Lewes, Vivian Byam Lighting, Gas. In Encyclopædia Britannica, 11th ed.; University Press: Cambridge, 1911; Vol. 16, pp 655–59.

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