Two at One Blow: The New Chemical Elements 110 and 111

摘要

Nothing significant has happened at the very end of the periodic table for about a decade, since a research group around Peter Armbrustcr, Sigurd Hofmann, and Gottfried Miinzen-berg produced and identified the three then heaviest chemical elements—element 107 in February 1981. 109 in August 1982, and 108 in March 1984--at the heavy-ion accelerator UNILAC of the Gesellschaft fur Schwerionenforschung (GS1) in Darmstadt (Germany). Rather, scepticism about progress beyond this limit seemed to be appropriate. "Their synthesis [of the heaviest nuclei] is strongly hindered -much more than was initially anticipated. It is this hindrance rather than the decreasing nuclear stability which seems to presently limit the extent of the periodic table: even heavier elements should be able to exist, but no way has yet been found to produce them" is pointed out in 1988 in a report in this journal. Nuclear properties are the key when the limit of the periodic table is approached. The electron shell does not play a role here, but it is decisive, of course, if we ask where the heaviest elements are located in the periodic table and whether its systematics continues consistently up to this point.