Difference between revisions of "Boron"

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{{Infobox element
 
{{Infobox element
−
|name = hydrogen
+
|name = boron
−
|symbol = H
+
|symbol = B
 
|left = [[beryllium]]
 
|left = [[beryllium]]
 
|right = [[carbon]]
 
|right = [[carbon]]
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|atomic-number = 5
 
|atomic-number = 5
 
|atomic-weight = 10.811(7)
 
|atomic-weight = 10.811(7)
−
|configuration = 1s<sup>2</sup> 2s<sup>2</sup> 2p<sup>1</sup>
+
|configuration = [He] 2s<sup>2</sup> 2p<sup>1</sup>
−
|phys-ref = <ref name="NIST">{{NIST chemistry | name = Boron | id = InChI=1S/B | accessdate = 2010-09-21}}.</ref>
+
|phys-ref = <ref name="NIST">{{NIST chemistry | name = Boron | id = InChI=1S/B | accessdate = 2010-09-21}}.</ref><ref name="G&E">{{Greenwood&Earnshaw1st|pages=155–242}}.</ref>
−
|melting-point = ''ca.'' 2300&nbsp;°C
+
|melting-point = ''ca.'' 2300&nbsp;°C (2573&nbsp;K)
−
|boiling-point = ''ca.'' 2550&nbsp;°C
+
|boiling-point = ''ca.'' 2550&nbsp;°C (2823&nbsp;K)
−
|chem-ref = <ref>{{Allred (1961)}}.</ref>
+
|density = 2.35 g cm<sup>−3</sup>
 +
|resistivity = 0.67 MΩ cm
 +
|chem-ref = <ref name="G&E"/><ref>{{Allred (1961)}}.</ref>
 
|electronegativity = 2.04 (Pauling)
 
|electronegativity = 2.04 (Pauling)
 
|solubility = insoluble
 
|solubility = insoluble
−
|IE-ref = <ref>{{NSRDS-NBS 34}}.</ref>
+
|IE-ref = <ref>{{citation | first1 = B. | last1 = Edlén | first2 = A. | last2 = Ölme | first3 = G. | last3 = Herzberg | first4 = J. W. C. | last4 = Johns | title = Ionization Potential of Boron, and the Isotopic and Fine Structure of 2s2p<sup>2</sup> <sup>2</sup>''D'' | journal = J. Opt. Soc. Am. | volume = 60 | issue = 7 | pages = 889–91 | year = 1970 | doi = 10.1364/JOSA.60.000889}}.</ref><ref>{{citation | last1 = Brown | first1 = C. M. | last2 = Tilford | first2 = S. G. | last3 = Ginter | first3 = M. L. | title = Absorption spectrum of B&nbsp;I in the 1350–1900-Å region | journal = J. Opt. Soc. Am. | year = 1974 | volume = 64 | issue = 6 | pages = 877–79 | doi = 10.1364/JOSA.64.000877}}.</ref><ref>{{NSRDS-NBS 34}}.</ref>
 
|IE1 = 8.298 024(18) eV<br/>800.6377(17) kJ mol<sup>−1</sup>
 
|IE1 = 8.298 024(18) eV<br/>800.6377(17) kJ mol<sup>−1</sup>
 
|IE2 = 25.154 eV<br/>2427.0 kJ mol<sup>−1</sup>
 
|IE2 = 25.154 eV<br/>2427.0 kJ mol<sup>−1</sup>
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|EA-ref = <ref>{{citation | last1 = Scheer | first1 = Michael | last2 = Bilodeau | first2 = René C. | last3 = Haugen | first3 = Harold K. | title = Negative ion of boron: An experimental study of the <sup>3</sup>''P'' ground state | journal = Phys. Rev. Lett. | year = 1998 | volume = 80 | issue = 12 | pages = 2562–65 | doi = 10.1103/PhysRevLett.80.2562}}.</ref>
 
|EA-ref = <ref>{{citation | last1 = Scheer | first1 = Michael | last2 = Bilodeau | first2 = René C. | last3 = Haugen | first3 = Harold K. | title = Negative ion of boron: An experimental study of the <sup>3</sup>''P'' ground state | journal = Phys. Rev. Lett. | year = 1998 | volume = 80 | issue = 12 | pages = 2562–65 | doi = 10.1103/PhysRevLett.80.2562}}.</ref>
 
|EA1 = 0.279 743(44) eV<br/>26.9910(42) kJ mol<sup>−1</sup>
 
|EA1 = 0.279 743(44) eV<br/>26.9910(42) kJ mol<sup>−1</sup>
−
|radius-ref = <ref>{{Cordero et al. (2008)}}.</ref>
+
|radius-ref = <ref>{{Cordero et al. (2008)}}.</ref><ref>{{Shannon (1976)}}.</ref>
 
|covalent-radius = 84 pm
 
|covalent-radius = 84 pm
−
|thermo-ref = <ref>{{CODATA thermo}}.</ref>
+
|ionic-radius = 25 pm (B<sup>3+</sup>, ''T<sub>d</sub>'')<br/>41 pm (B<sup>3+</sup>, ''O<sub>h</sub>'')
 +
|thermo-ref = <ref name="NIST"/><ref>{{CODATA thermo}}.</ref>
 
|entropy = 5.90(8) J K<sup>−1</sup> mol<sup>−1</sup>
 
|entropy = 5.90(8) J K<sup>−1</sup> mol<sup>−1</sup>
 
|enthalpy-atomization = 565(5) kJ mol<sup>−1</sup>
 
|enthalpy-atomization = 565(5) kJ mol<sup>−1</sup>
 
|entropy-atomization = 147.54(8) J K<sup>−1</sup> mol<sup>−1</sup>
 
|entropy-atomization = 147.54(8) J K<sup>−1</sup> mol<sup>−1</sup>
 +
|enthalpy-fusion = 48.93 kJ mol<sup>−1</sup>
 
|CAS-number = 7440-42-8
 
|CAS-number = 7440-42-8
 
|EC-number = 231-151-2
 
|EC-number = 231-151-2

Latest revision as of 10:11, 27 December 2010

beryllium ← boron → carbon
–
↑
B
↓
Al
Atomic properties
Atomic number 5
Standard atomic weight 10.811(7)
Electron configuration [He] 2s2 2p1
Physical properties[1][2]
Melting point ca. 2300 °C (2573 K)
Boiling point ca. 2550 °C (2823 K)
Density 2.35 g cm−3
Electric resistivity 0.67 MΩ cm
Chemical properties[2][3]
Electronegativity 2.04 (Pauling)
Solubility in water insoluble
Ionization energies[4][5][6]
1st 8.298 024(18) eV
800.6377(17) kJ mol−1
2nd 25.154 eV
2427.0 kJ mol−1
3rd 37.930 eV
3659.7 kJ mol−1
4th 259.368 eV
25025.2 kJ mol−1
5th 340.217 eV
32826.0 kJ mol−1
Total 670.967 eV
64738.5 kJ mol−1
Electron affinity[7]
0.279 743(44) eV
26.9910(42) kJ mol−1
Atomic radii[8][9]
Covalent radius 84 pm
Ionic radius 25 pm (B3+, Td)
41 pm (B3+, Oh)
Thermodynamic properties[1][10]
Standard entropy 5.90(8) J K−1 mol−1
Enthalpy change of atomization 565(5) kJ mol−1
Entropy change of atomization 147.54(8) J K−1 mol−1
Enthalpy change of fusion 48.93 kJ mol−1
Miscellaneous
CAS number 7440-42-8
EC number 231-151-2
Where appropriate, and unless otherwise stated, data are given for 100 kPa (1 bar) and 298.15 K (25 °C).
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Boron (symbol: B) is a chemical element.

Notes and references

Notes

References

  1. ↑ 1.0 1.1 Boron. In NIST Chemistry WebBook; National Institute for Standards and Technology, <http://webbook.nist.gov/cgi/inchi/InChI%3DInChI=1S/B>. (accessed 21 September 2010).
  2. ↑ 2.0 2.1 Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 155–242. ISBN 0-08-022057-6.
  3. ↑ 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.
  4. ↑ Edlén, B.; Ölme, A.; Herzberg, G.; Johns, J. W. C. Ionization Potential of Boron, and the Isotopic and Fine Structure of 2s2p2 2D. J. Opt. Soc. Am. 1970, 60 (7), 889–91. DOI: 10.1364/JOSA.60.000889.
  5. ↑ Brown, C. M.; Tilford, S. G.; Ginter, M. L. Absorption spectrum of B I in the 1350–1900-Å region. J. Opt. Soc. Am. 1974, 64 (6), 877–79. DOI: 10.1364/JOSA.64.000877.
  6. ↑ 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>.
  7. ↑ Scheer, Michael; Bilodeau, René C.; Haugen, Harold K. Negative ion of boron: An experimental study of the 3P ground state. Phys. Rev. Lett. 1998, 80 (12), 2562–65. DOI: 10.1103/PhysRevLett.80.2562.
  8. ↑ 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.
  9. ↑ 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.
  10. ↑ Cox, J. D.; Wagman, D. D.; Medvedev, V. A. CODATA Key Values for Thermodynamics; Hemisphere: New York, 1989. ISBN 0891167587, <http://www.codata.org/resources/databases/key1.html>.

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