91av

THE celebrated discovery of the heaviest element ever found was just an
illusion. Red-faced scientists who thought they’d found element 118 in 1999 have
now backed down and retracted their claim.

The element—dubbed “ununoctium”—was supposedly discovered at
Lawrence Berkeley National Laboratory in California. A team led by Ken Gregorich
fired high-energy krypton ions at a lead target. Within the debris, they thought
they could see the telltale disintegration of element 118, containing 118
protons and 175 neutrons, along with its decay product, element 116
(91av, 19 June 1999, p 27).

The new elements decayed in a split second. But the fact that they popped up
at all backed theories, touted since the 1970s, that there’s an “island of
stability” for atoms with approximately 114 protons and 184 neutrons.

Scientists in Germany and Japan tried to replicate the results, but without
success. Prompted by this, Gregorich’s team reanalysed the original data with
different software. They failed to find any signs of the decay chains they
thought they’d seen in 1999. So they have withdrawn the claims in a note
submitted to Physical Review Letters, which carried the original
report. “We retract our published claim for the synthesis of element 118,” the
scientists say.

In a statement, the Berkeley lab director Charles Shanks said the team is
keen to put the record straight. “There are many lessons here,” he said. “The
path forward is to learn from the mistakes and to strengthen the resolve to find
the answers that nature still hides from us.”

“The search for the extremely heavy elements is very competitive—I
think there’s a great deal of pressure to succeed,” comments Mark Winter, a
chemist at the University of Sheffield. “But if they think the results aren’t
correct, they’ve done the right thing.” He says that it remains to be seen if
the elusive island of stability exists or not.