Gallium

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zinc ← gallium → germanium
Al
↑
Ga
↓
In
Atomic properties
Atomic number 31
Standard atomic weight 69.723(1)
Electron configuration [Ar] 3d10 4s2 4p1
Physical properties[2][3]
Melting point 29.770(4) °C (302.920(4) K)[note 1]
Boiling point 2403 °C (2676 K)
Density 5.904 g cm−3 (20 °C)
Electric resistivity 25.8 µΩ cm[note 2]
Chemical properties[3][4]
Electronegativity 1.81 (Pauling)
Solubility in water insoluble, unreactive
Ionization energies[5][6]
1st 5.999 30 eV
578.844 kJ mol−1
2nd 20.5141 eV
1979.32 kJ mol−1
3rd 30.71 eV
2963 kJ mol−1
Electron affinity[7]
0.430(30) eV
41.5(29) kJ mol−1
Atomic radii[3][8][9]
Covalent radius 122 pm
Metallic radius 135 pm[note 3]
Ionic radius 61 pm (Ga3+, Td)
76.0 pm (Ga3+, Oh)
Thermodynamic properties[2]
Standard entropy 40.83 J K−1 mol−1
Enthalpy change of fusion 5.58 kJ mol−1
Enthalpy change of vaporization 271.96 kJ mol−1
Miscellaneous
CAS number 7440-55-3
EC number 231-163-8
Where appropriate, and unless otherwise stated, data are given for 100 kPa (1 bar) and 298.15 K (25 °C).
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Gallium (symbol: Ga) is a chemical element in group 13 of the periodic table.

Notes and references

Notes

  1. ↑ The melting point of gallium is a defining point on the International Temperature Scale 1990 (ITS-90), with a value of 302.9146 K (29.7646 °C).[1]
  2. ↑ Value for liquid gallium at 30 °C. The electric resistivity of solid gallium is highly anisotropic: a 17.5 µΩ cm, b 8.20 µΩ cm, c 55.3 µΩ cm.[3]
  3. ↑ Gallium has a unique solid state structure, in which each gallium atom has one very close neighbour at 244 pm and six futher neighbours, two each at 270, 273 and 279 pm.[3]

References

  1. ↑ Preston-Thomas, H. The International Temperature Scale of 1990 (ITS-90). Metrologia 1990, 27 (1), 3–10. DOI: 10.1088/0026-1394/27/1/002, as corrected by Preston-Thomas, H. Erratum: The International Temperature Scale of 1990 (ITS-90). Metrologia 1990, 27 (2), 107. DOI: 10.1088/0026-1394/27/2/010.
  2. ↑ 2.0 2.1 Gallium. In NIST Chemistry WebBook; National Institute for Standards and Technology, <http://webbook.nist.gov/cgi/inchi/InChI%3D1S/Ga>. (accessed 27 December 2010).
  3. ↑ 3.0 3.1 3.2 3.3 3.4 Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 243–95. ISBN 0-08-022057-6.
  4. ↑ 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.
  5. ↑ Johansson, I.; Litzen, U. The term systems of the neutral gallium and indium atoms derived from new measurements in the infrared region. Ark. Fys. 1967, 34, 573.
  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. ↑ Williams, W. W.; Carpenter, D. L.; Covington, A. M.; Koepnick, M. C.; Calabrese, D.; Thompson, J. S. Laser photodetachment electron spectrometry of Ga−. J. Phys. B: At., Mol. Opt. Phys. 1998, 31 (8), L341–45. DOI: 10.1088/0953-4075/31/8/003.
  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.

External links

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