'Superheavy' Discovery

Updated August 5, 2020 | Infoplease Staff

New elements pave the way for isotopes

Source: Lawrence Berkeley Labs

Victor Ninov (left) and Ken Gregorich were part of the team to discover elements 118 and 116.

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Please note: Just three years after a group of Berkeley scientists announced the discovery of the heaviest known elementâelement 118, or ununoctiumâthey officially retracted the news, saying they had been in error. See Elusive Element for more.

On June 8, 1999, scientists at the U.S. Department of Energy's Lawrence Berkeley Laboratory in California announced pushing the limits of matter by creating elements 118 and its immediate decay product, element 116.

The new "superheavy" elements were discovered at Berkeley Laboratory's 88-inch cyclotron by bombarding targets of lead-208 with a high energy and high intensity beam of krypton-86 ionsâat an average current of 2 trillion ions per second.

A quick life

Within less than a millisecond after its creation, the nucleus of element 118 radioactively decays by emitting an alpha particle, leaving behind an isotope of element 116.

The second element, 116, has mass number 289, containing 116 protons and 173 neutrons. This daughter element 116 is also radioactive and alpha-decays into an isotope of element 114. The chain of successive alpha decays continues until at least element 106, Seaborgium.

What's it all mean?

Although both elements almost instantly decay into other elements, the announcement is important because it supports theories of an "island of stability" for nuclei (in which the decay lasts for a period of time instead of decaying instantly).

The success in producing the new superheavy elements opens up a whole new world of possibilities using similar reactions: new elements and isotopes.

Earlier in 1999, element 114 had possibly been observed in experiments at the Joint Institute for Nuclear Research at Dubna, Russia, but has not yet been confirmed.

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