Russian scientists add new element to periodic table

Russian scientists add new element to periodic table

By DAVID KINNEY

(July 15, 1999 2:44 a.m. EDT http://www.nandotimes.com) - Physicists in Russia have created a new, super-heavy element that lasted a surprisingly long 30 seconds before disintegrating, according to a report in Thursday's issue of the journal Nature. Using an atom smasher to bombard plutonium with calcium ions, the physicists created an element with an atomic weight of 114.

The newest addition to the periodic table has yet to be named.

Ninety-four elements exist in nature. Scientists have spent 60 years creating elements in the lab, registering 21 so far. But some of the more recent elements were so unstable that they disintegrated in milliseconds.

For decades, physicists have theorized the existence of super-heavy manmade elements with a much longer life. These elements would make up an "island of stability."

In the study, researchers at the Joint Institute for Nuclear Research in Dubna, Russia, reported creating two atoms of element 114 that lasted for as long as 30 seconds before flickering out. This, they say, is proof the island exists.

The discovery, and more recent creations of even heavier elements, have no practical applications as far as today's scientists know.

But for academics, it's thrilling. The study of super-heavies could shed light on supernovas and origins of the universe. And chemists are interested in how they bond with compounds.

The new manmade elements are numbered according to how many protons are in their nuclei, not by their order of discovery. Numbers 95 through 112 were created between 1944 and 1996. In the past year, scientists have created not just 114, but also 116 and 118. The ones in between have not yet been created.

For decades, scientists thought one isotope, or version, of element 114 - with 114 protons and 184 neutrons - would be very stable because its nucleus would have a full complement of neutrons and protons. No more could be squeezed inside.

Late last year, the Dubna scientists made an isotope of element 114 with 175 neutrons. In March, the lab created another 114 isotope, but it had only 173 neutrons and was therefore less stable than the first one they created.

This year, another major lab trying to create elements, Lawrence Berkeley National Laboratory in California, 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. It lasted for milliseconds.

These three types of 114 are just off the "island of stability," scientists say, because they are all short of the 184 neutrons needed. But physicists say they are in "shallow water," and that's proof enough.

If they can create a 114 isotope with 184 neutrons, they would reach real stability: perhaps a life measured in years.

One physicist, Albert Ghiorso of Lawrence Berkeley, said he is skeptical the Russians really did create such an element. He said that with their setup, it is too difficult to pinpoint a single atom among all the collision byproducts.

But Neil Rowley, of the Institute for Subatomic Research in France, is convinced the Dubna observations are real. "Everything behaves the way it ought to," he said.