| Share


ununoctium (ōnˌōnŏkˈtēəm) [key], artificially produced radioactive chemical element; symbol Uuo; at. no. 118. Scientists from the Joint Institute for Nuclear Research in Dubna, Russia, and Lawrence Livermore National Laboratory in California collaborated in the discovery of ununoctium in experiments conducted in 2002 and 2005. They bombarded atoms of californium-249 with ions of calcium-48. Among the products of the bombardments were atoms of ununoctium-294 (one in 2002, two in 2005), each of which decayed into an atom of livermorium by emitting an alpha particle. Uuo-294 has a half-life of approximately 0.89 msec. No name has yet been adopted for element 118, which is therefore called ununoctium, from the Latin roots un for one and oct for eight, under a convention for neutral temporary names proposed by the International Union of Pure and Applied Chemistry (IUPAC) in 1980.

In 1999 a research team at the Lawrence Berkeley National Laboratory in Calif. bombarded lead-208 atoms with high-energy krypton-86 ions to create what an analysis showed to be three atoms of element 118 with mass number 293 and a half-life of less than a millisecond. In 2001, however, the team retracted its claim to have produced ununoctium after other laboratories failed to reproduce their results and after a reanalysis of the original data did not show the production of element 118. A subsequent investigation suggested that the original finding was the result of fraud on the part of one of the team scientists.

See also synthetic elements; transactinide elements; transuranium elements.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on ununoctium from Infoplease:

  • Periodic Table of the Elements: Ununoctium - Periodic Table of the Elements: Ununoctium Atomic Number: 118 Atomic Symbol: Uuo Ununoctium Atomic ...
  • Uuo - Uuo Uuo, symbol for the element ununoctium.
  • element 118 - element 118: element 118: see ununoctium.
  • ununhexium - ununhexium ununhexium , artificially produced radioactive chemical element; symbol Uuh; at. no. ...
  • Element 118 - 'Superheavy' Discovery New elements pave the way for isotopes Victor Ninov (left) and Ken ...

See more Encyclopedia articles on: Compounds and Elements

24 X 7

Private Tutor

Click Here for Details
24 x 7 Tutor Availability
Unlimited Online Tutoring
1-on-1 Tutoring