Researchers take an element off the table

Reach for your Magic Marker: The periodic table has lost an element.

Researchers at Lawrence Berkeley (Calif.) National Laboratory have retracted their claim from 2 years ago that they had created the heaviest member of the periodic table so far–element 118. The retraction dims hopes that scientists will soon find a cache of superheavy elements that would make uranium seem like a lightweight.

In 1999, the Berkeley team had reported the creation of three atoms of element 118 in a particle accelerator (SN: 6/12/99, p. 372; http://www.sciencenews.org/sn_arc99/6_12_99/fob2.htm.). At that time, the group concluded that each fleeting atom of element 118 rapidly decayed into other elements, including never-before-seen element 116.

“There really wasn’t any reason to disbelieve it,” comments Ken Moody of Lawrence Livermore (Calif.) National Laboratory. “They had a theoretical prediction . . . and it looked like what they found agreed with the theory.”

Now, in a statement prepared for Physical Review Letters, the journal that published the initial results, the researchers indicate that attempts by their lab and by facilities in Germany and Japan haven’t reproduced the 1999 results. “Right now, I think we’ve all kind of pushed to the limit, and it’s not happening,” says Berkeley team member Kenneth E. Gregorich.

Furthermore, reanalysis of the original data doesn’t show the production of 118 and its decay chain, says Gregorich. “All the isotopes in the decay chain from our claim, you can forget about,” he says. However, different experiments by researchers from Livermore and the Joint Institute for

Nuclear Research in Dubna, Russia, appear to have since created element 116 directly, he notes.

The Berkeley lab has launched an investigation to find out how the original data were misinterpreted, says Pier Oddone, the lab’s deputy director. “Some glitch happened in that analysis,” he says.

“It’ll be very interesting to find out what their investigation shows up, whether it’s a computer problem or something else,” says Moody, who worked on the Dubna-Livermore 116 experiments. “I’m hoping there will be some reasonable explanation that we can all learn from.

“It’s tough when an element disappears,” he adds.

Particle physicists had hailed 118’s apparent creation as a breakthrough that would lead quickly to many additional stable elements beyond the far end of the periodic table. Now, such prospects are less promising, says Gregorich.

Some researchers remain optimistic. The Berkeley team “came to the conclusion that they could not claim the synthesis of element 118, but of course it’s not a proof that 118 does not exist,” says Sigurd Hofmann of GSI, a research center in Darmstadt, Germany. “We hope that eventually these superheavies that 118 belongs to can be made.”

Perhaps, then, it would be better to use pencil, rather than ink, to cross out element 118.

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