THE discovery of a new isotope of element 114 has confirmed that an 鈥渋sland鈥�
of stable, even heavier elements exists.
Most atoms heavier than uranium are unstable, with life spans measured in
microseconds. But physicists calculate that within certain ranges, the more
neutrons you add and the heavier the elements become, the more stable they
become.
In fact, there should be an 鈥渋sland of stability鈥� where superheavy atoms have
lifetimes of many years. Atomic nuclei with 114 protons and 184 neutrons should
occupy the peak of the island.
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No one has made such a neutron-rich atom of element 114. But in January,
scientists at the Joint Institute for Nuclear Research in Dubna, Russia,
reported the first nucleus of element 114, containing 175 neutrons
(This Week, 30 January, p 14).
Sure enough, it was very stable, with a lifetime of 20
seconds. However, one nucleus of one isotope could not confirm that the island
of stability exists.
Now a team led by Alexander Yeremin at the Dubna institute has created two
lighter nuclei of element 114, containing 173 neutrons. These had lifetimes of
about five seconds鈥攋ust as expected if theories about the stability island
are on the right track (Nature, vol 400, p 242).
鈥淚t鈥檚 fantastically important work,鈥� says Neil Rowley of the Institute for
Subatomic Research in Strasbourg, France. 鈥淲e have reached the island of
stability, but there is a very high mountain to climb,鈥� adds Andrei Popeko, one
of the Dubna team. He thinks some of the superheavy stable elements may exist in
space or even here on Earth.