Main Page | See live article | Alphabetical index


Darmstadtium - Unununium - Ununbium

Full table
Known properties
Name, Symbol, NumberUnununium, Uuu, 111
Chemical series Transition metals
Group, Period, Block11, 7 , d
Appearance unknown; probably metallic,
silvery white or gray
Atomic weight [272] amu
Electron configuration probably [Rn]55f14 6d10 7s1
e- 's per energy level2, 8, 18, 32, 32, 18, 1
State of matter Presumably a solid
Unununium is a chemical element in the periodic table that has the symbol Uuu and atomic number 111. It has an atomic weight of 272 making it one of the super-heavy atoms. It is a synthetic element whose only known isotope has a half-life of around 15 ms before it decays into meitnerium. Due to its presence in Group 11 it is a transition metal and so probably metallic and solid.


It was first created at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany on December 8, 1994. Only three atoms of it have been created (all Uuu-272), by the fusion of bismuth-209 and nickel-64 in a linear accelerator (nickel was bombarded onto the target).

It is named Unununium, as in 1-1-1-ium, a temporary IUPAC systematic element name. There is an ongoing element naming controversy over what this element should be called.

External links