Heaviest known element created

U.S. and Russian researchers said Monday they had created element 118, the heaviest known element.

It is the fifth ultraheavy element produced by the team at Lawrence Livermore National Laboratory in Livermore, Calif., and the Joint Institute for Nuclear Research in Dubna, Russia, which has come to dominate the creation of rare, short-lived elements.

Although they produced only three atoms of element 118, and each lasted for less than one-thousandth of a second, the team said there was less than one chance in 10,000 that there was a mistake in identification.

A team at Lawrence Berkeley National Laboratory in Berkeley, Calif., announced in 1999 that it had created element 118 by a different route, but those results were subsequently shown to have been fabricated by physicist Victor Ninov, who was later fired.

The findings will be published today in the journal Physical Review C.

The discovery has no immediate application, but it brings researchers closer to discovering what theoretical physicists have described as an "island of stability" — a group of ultraheavy elements that may survive minutes or even hours, compared with the fractions of a second now seen with the heaviest creations. That would allow researchers to begin to understand the chemistry of the elements, perhaps even to discover some unique chemical properties.

Only 92 elements exist in nature.

The team used a cyclotron at Dubna to bombard a target of the man-made element californium-249 with calcium ions.

Each atom of the new element had 118 protons and 179 neutrons in its nucleus, giving it an atomic weight of 297. If confirmed, the still-unnamed element would fall directly below radon in the periodic table of the elements.