| The Columbia Encyclopedia, Sixth Edition. 2001-07. |
| |
| ununbium |
| |
| |
(y n n´b  m) (KEY) , artificially produced radioactive chemical element; symbol Uub; at. no. 112; mass number of most stable isotope 285; m.p., b.p., sp. gr., and valence unknown. Situated in Group 12 of the periodic table, it is expected to have properties similar to those of zinc, cadmium, and mercury. | 1 | | In 1996 an international research team led by Peter Armbruster and Sigurd Hofmann at the Institute for Heavy Ion Research at Darmstadt, Germany bombarded lead-208 atoms with high-energy zinc-70 ions. In a two-week experiment, one of the resultant atoms was unambiguously identified as an isotope of element 112 with mass number 277 and a half-life of 280 microseconds. No name has yet been adopted for element 112, which is therefore called ununbium, from the Latin roots un for one and bi for two, under a convention for neutral temporary names proposed by the International Union of Pure and Applied Chemistry (IUPAC) in 1980. | 2 | | See also synthetic elements; transactinide elements; transuranium elements. | 3 |
| |
| | | The Columbia Encyclopedia, Sixth Edition. Copyright © 2007 Columbia University Press. |
|
|
