| Seaborgium - Sg
CAS: 54038-81-2 Description: Classification: Transactinide Date of Discovery: 1974 Discoverer: Albert Ghiorso Name Origin: After Glenn T. Seaborg Other Name(s): Unnilhexium (Unh), Rutherfordium (Rf) |
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Atomic Number: 106
Number of Neutrons: 157 Atomic Mass: (263) amu Melting Point: Boiling Point: Density (293 K): Atomic volume: Electrical resistivity: Thermal conductivity: Enthalpy of atomization: Enthalpy of vaporization: Enthalpy of fusion: Specific heat capacity: |
Energy levels: 2-8-18-32-32-12-2
Electron configuration: [Rn]5f 146d47s2 Crystal Structure: Atomic radius: Covalent radius: Oxidation States: Electronegativity, Pauling: Electron affinity: First ionization energy: 2nd ionization energy: 3rd ionization energy: Polarizability: |
| Isotope | Atomic Mass | Half-life | Decay Mode | Spin |
| 259Sg | 259.1147 | 0.5 s |  , SF |
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| 260Sg | 260.11444 | 4 ms | , SF |
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| 261Sg | 261.1164 | 0.3 s | , SF |
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| 263Sg | 263.1186 | 0.8 s | SF, |
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| 265Sg | 265.121 | < 30 s | ; SF |
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| 266Sg | 266.122 | < 30 s | ; SF |
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Element 106 - The discovery of Element 106 took place in 1974 almost simultaneously at the Lawrence-Berkel Laboratory and at the Joint Institute for Nuclear Research at Dubna (near Moscow). The Berkeley Group, under direction of Ghiorso, used the Super-Heavy Ion Linear Accelerator (Super HILAC) as a source of heavy 18O ions to bombard a 259 µg target of 249Cf. This resulted in the production and positive identification of 263106, which decayed with a half-life of 0.9 ± 0.2 sec by the emission of alpha particles as follows:
263106  259104 255No
The Dubna Team, directed by Flerov and Organessian, produced heavy ions of 54Cr with their 310-cm heavy-ion cyclotron to bombard 207Pb and 208Pb and found a product that decayed with a half-life of 7 ms. They assigned 259106 to this isotope. Earlier, the IUPAC proposed a temporary name of unnilhexium for this element. The Berkeley Group, who first claimed positive identification, proposed the name seaborgium to Element 106. In 1994 the IUPAC recommended the name rutherfordium with the symbol Rf to this element; however, this name is being challenged by the Berkeley Group. The name rutherfordium had been used for many year for Element 104. It is now thought six isotopes of Element 106 have been identified. Two of the isotopes are believed to have half-lives of about 30 sec. LINKS: An Early History of LBNL by Dr. Glenn T. Seaborg "Seaborgium" Approved for Element 106 Return
Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998. |
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