The element ununium or unununium or as it is now known roentgenium.
Symbol: Was Uuu now Rg
Atomic Number: 111
Atomic Mass: 272 amu (atomic mass units)
Melting Point: Unknown
Boiling Point: Unknown
Number of Protons: 111
Number of Electrons: 111
Number of Neutrons: 161
Classification: Metallic
Crystal Structure: Unknown
Density @ 293 K: Unknown
Color: Unknown
Ununium or unununium was a temporary name given to the man made element number 111. Un means one so the original name meant one-one-one. It is found within group 11, period 7 and block d of the periodic table of elements. This element has now been re-named roentgenium in honor of the famous scientist Wilhelm Conrad Roentgen. Roentgen was the German physicist who won the Nobel Prize in physics in 1901 for his discovery of X-rays. The name roentgenium has not yet been ratified by the International Union for Pure and Applied Chemistry (IUPAC) but it is probable that it will remain the name for this element.
It was discovered on the eighth of December 1994 by a team of scientists led by Peter Armbruster and Gottfried Munzenber at the Gesellschaft fur Schwerionenforschung (GSI) in Darmstadt, Germany. In part of their research on “super heavy” atoms this team bombarded a target of bismuth-209 atoms with nickel-64 ions using a linear accelerator. Observing the results of this experiment they detected just three atoms of a new element now known to be roentgenium. The bismuth atom and the nickel ion combined to form the new element with the loss of a single neutron. The isotope produced by this experiment was roentgenium-272 which has a half-life of approximately 1.5 milliseconds. No stable isotopes of roentgenium have been discovered. The most stable isotope produced for this element to date is roentgenium-280 which has a half-life of about 3.6 seconds and decays via alpha decay to yield meitnerium-276.
The short half-life of this man-made element means we have been able to find out very little about its properties. Only a few atoms have ever been made and it is unlikely that enough allow the measurement of its bulk properties such as density, melting point, boiling point or crystal form will ever be produced. It is radioactive so if this element was ever to be made in any quantity extreme care would be required in its handling. From the elements position within group 11 of periodic table it can be deduced that it is a metal as other elements within this group include gold, copper and silver. It is probably silvery white or grey in color.
The element has no known industrial uses nor is it ever likely to have such uses. It is currently of interest only within the laboratory setting and the on-going research into the “super heavy” elements.
