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Thursday, July 15, 1999 Published at 16:36 GMT 17:36 UK


Sci/Tech

Russians create new heavy element


Russian scientists have made a new super-heavy element in the lab that does not exist in nature. But what is really remarkable is that this collection of protons and neutrons stayed together for about 30 seconds before starting to decay.

Such giant elements are usually highly unstable and decay with half-lives that can be measured in milliseconds or less.

The new addition to the periodic table has the atomic number 114 - that is to say, it has 114 protons. The scientists working at the Flerov Laboratory of Nuclear Reactions in Dubna made two isotopes of the element. One had 175 neutrons, the other had 173.

By comparison, the heaviest element found in nature - in sizeable quantities - is the most common form of uranium. This contains just 92 protons and 146 neutrons.

Artificial elements can only be synthesized in nuclear reactors or particle accelerators. In this case, the isotopes were created by bombarding targets of plutonium with beams of calcium ions.

'Island of stability'

It has been a good year for scientists working in this field. The Lawrence Berkeley National Laboratory in California announced in June that they had forged the heaviest element yet, 118, and when it decayed, it morphed into element 116, then an isotope of 114 with even fewer neutrons than Dubna's.

For more than 30 years physicists have predicted that there probably exists an "island of stability" for nuclei with around 184 neutrons - isotopes that would not disappear almost as soon as they are created. Calculations suggest that isotopes on this island could, theoretically, have half-lives measurable in years.

The new Russian isotopes, with 173 and 175 neutrons and half-lives measured in seconds, appears to confirm the theory.

Scientists cannot make anything with these artificial elements. But they do provide valuable insights into the structure of atomic nuclei.

Anyone interested in knowing what element 114 will be called may have to wait a while. The international committee responsible for naming process can take several years before reaching a decision.

The new research has been published in the journal Nature.



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New superheavy elements created





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