June 11, 2009
New ‘Super-Heavy’ Element Added To Periodic Table
A team of German scientists has been credited with the discovery of the new "super-heavy" element 112 more than ten years after intensive laboratory work first yielded a single atom of the novel form of matter.
But before the element can be officially added to the periodic table, Sigurd Hofmann and his team of researchers at the Center for Heavy Ion Research in Darmstadt, Germany have to think of a name for their discovery.Professor Hofmann's pursuit to expand the periodic table first started in 1976. Now, the fusion experiments that he and his colleagues used to create the new element have also uncovered the existence of five additional undiscovered elements with atomic numbers 107-111.
Among scientist, these rare atoms are known as "super-heavy elements" "” a reference to the large number of protons and neutrons located in the nucleus of the atom where the overwhelming majority of every element's mass is located.
To create element 112, Professor Hofmann's group used a 1.2 meter-long particle accelerator to shoot a concentrated beam of zinc ions at lead atoms, causing the nuclei of the two elements to fuse and form the nucleus of the new element.
These "super-heavy" new nuclei are very unstable and begin to fall apart or "decay" almost as soon as they form. The lifespan of these experimentally created elements are generally measured in milliseconds.
When the unstable atom decays, energy is released which scientists are then able to measure to determine various characteristics of the element, such as the exact size of the nucleus.
The successful fusion of two atoms is actually an extremely rare event, and scientists require increasingly powerful particle accelerators that are able to fire longer in attempts to create the elusive, unstable elements.
This explains why it took such a long time before the International Union of Pure and Applied Chemistry (IUPAC) could officially recognize element 112, as its existence had to be independently confirmed by another laboratory.
Thus far only four atoms of the wily element have ever been observed.
The IUPAC has temporarily dubbed the element ununbium, meaning "one one two" in Latin. Professor Hofmann's team is now charged with the daunting task of proposing its official name.
Hofmann says that groups of experimental chemists around the world are now racing to create new, even heavier elements in a spirit of "friendly competition."
In 2006, researchers at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia, claimed to have discovered element 118 by blasting a plate of the element californium with a beam of calcium ions.
"We have confirmed some of these results," Professor Hofmann told reporters.
Hofmann's group is not content to rest on their laurels, however, and are already attempting an even more ambitious bit of experimentation.
"We tried the same experiment to get to element 120. We've not seen it yet, but we believe the element exists and, with a long enough beam time, it could be produced," he explained.
"It's certainly a race, and it's nice to be first."
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