Scientists create new element -- the heaviest
substance
Posted on : Tue, 17 Oct 2006 05:50:00 GMT
Author : Brian Holmes
News Category : General
NEW YORK: A team of American and Russian scientists said they have
discovered a new element, which is the heaviest substance known to
exist. Temporarily called Ununoctium, the new element -- No 118 --
has been discovered following years of scientific experiments in
four continents.
The last naturally occurring element in the Periodic Table was
discovered in 1925 and scientists have since been seeking to create
new heavier elements.
Scientists working at the Lawrence Livermore National Laboratory in
California and the Joint Institute for Nuclear Research in Dubna,
Russia, developed the new element by bombarding californium with
calcium ions to create 118.
This is the fifth ultraheavy element produced by the teams at the
two research centers, which have been dominating in creating rare,
short-lived elements.
Though they had produced 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.
Earlier in 1999, a team at Lawrence Berkeley National Laboratory in
Berkeley, California, had announced it had created element 118 by a
different route, but those results were found to be false as they
were fabricated by a physicist, Victor Ninov, who was later fired
by Berkeley.
Physicist Ken Moody of Livermoore, who led the team, said the team
selected a completely different nuclear reaction, performed with
completely different people in a different laboratory. He said
every experiment was checked and double-checked.
Element 118 has no immediate application, but it may lead
researchers closer to discovering what is theoretically possible --
what is called "island of stability" or 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. This
will also help researchers to understand the chemistry of the
elements and even to discover some unique chemical
properties.
The scientists' team at Dubna used a cyclotron to bombard a target
of the man-made element californium-249 with ions of calcium-48.
The researchers said in two separate experiments, they bombarded
the target with 40,000,000,000,000,000,000 ions, producing three
atoms of element 118. Each atom had 118 protons and 179 neutrons in
its nucleus, giving it an atomic weight of 297.
The researchers then found that each atom first spit out an alpha
particle -- composed of two protons and two neutrons -- to become
the previously known element 116. That element, in turn, spit out
another alpha particle to become element 114, and then another to
become element 112. Element 112 fissioned into two atoms of roughly
equal size.
Element 118 will be just below radon in the Periodic Table of
elements and qualifies to be called noble gas. So far, scientists
have discovered only 92 elements that exist in nature, but
physicists have produced 18 more, which have been officially
recognized and named.
The Livermore-Dubna team has created elements 113, 114, 115 and
116, but none has been officially recognized, named and placed in
the Periodic Table, because the work has not been replicated by
other researchers.
The team is now planning to produce element 120 by bombarding a
plutonium target with a beam of iron ions.
The team's paper on the discovery is being published in the
journal, Physical Review C.
