seaborgium , artificially produced radioactive chemical element; symbol Sg; at. no. 106; mass number of most stable isotope 266; m.p., b.p., sp. gr., and valence unknown. Situated in Group 6 of the periodic table , it is expected to have properties similar to those of tungsten . The discovery of element 106 took place almost simultaneously in two different laboratories. In June, 1974, a Soviet team led by G. N. Flerov at the Joint Institute for Nuclear Research at Dubna reported bombarding lead-207 and lead-208 atoms with chromium-54 ions to produce an isotope with mass number 259 and a half-life of 7 msec. In Sept., 1974, an American research team led by A. Ghiorso at the Lawrence Berkeley National Laboratory reported bombarding californium-249 atoms with oxygen-18 ions to create an isotope with mass number 263 and a half-life of 0.9 sec. Because their work was independently confirmed first, the Americans suggested the name seaborgium to honor the American chemist Glenn T. Seaborg . An international committee decided in 1992 that the Berkeley and Dubna laboratories should share credit for the discovery. The syntheses of at least six isotopes of seaborgium, with half-lives ranging from 0.4 msec (Sg-260) to 30 sec (Sg-266), have been confirmed. In 1994 a committee of the International Union of Pure and Applied Chemistry (IUPAC), convened to resolve naming disputes for the transactinide elements , recommended that element 106 be named rutherfordium . In 1997,...
seaborgium , artificially produced radioactive chemical element; symbol Sg; at. no. 106; mass number of most stable isotope 266; m.p., b.p., sp. gr., and valence unknown. Situated in Group 6 of the periodic table , it is expected to have properties similar to those of tungsten . The discovery of element 106 took place almost simultaneously in two different laboratories. In June, 1974, a Soviet team led by G. N. Flerov at the Joint Institute for Nuclear Research at Dubna reported bombarding lead-207 and lead-208 atoms with chromium-54 ions to produce an isotope with mass number 259 and a half-life of 7 msec. In Sept., 1974, an American research team led by A. Ghiorso at the Lawrence Berkeley National Laboratory reported bombarding californium-249 atoms with oxygen-18 ions to create an isotope with mass number 263 and a half-life of 0.9 sec. Because their work was independently confirmed first, the Americans suggested the name seaborgium to honor the American chemist Glenn T. Seaborg . An international committee decided in 1992 that the Berkeley and Dubna laboratories should share credit for the discovery. The syntheses of at least six isotopes of seaborgium, with half-lives ranging from 0.4 msec (Sg-260) to 30 sec (Sg-266), have been confirmed. In 1994 a committee of the International Union of Pure and Applied Chemistry (IUPAC), convened to resolve naming disputes for the transactinide elements , recommended that element 106 be named rutherfordium . In 1997,...
