Unbibium

From Wikipedia, the free encyclopedia

122 Ubu ← unbibium → Ubt

↑
Ubb
↓
Usb
General
Name, Symbol, Number unbibium, Ubb, 122
Chemical series Superactinides
Group, Period, Block g2, 8, g
Appearance unknown
Standard atomic weight  g·mol−1
Electron configuration [Uuo] 5g2 8s2
Electrons per shell 2, 8, 18, 32, 34, 18, 8, 2
Physical properties
Phase presumably solid
Miscellaneous
Selected isotopes
Main article: Isotopes of unbibium
iso NA half-life DM DE (MeV) DP
References

Unbibium (pronounced /ənˈbɪbiəm/) or eka-thorium is the temporary name of a (purportedly) recently discovered[1] chemical element in the periodic table that has the temporary symbol Ubb and has the atomic number 122.

Contents

[edit] History

The first attempt to synthesise element 122 was performed in 1972 by Flerov et al at Dubna, JINR, using the hot fusion reaction:


\,^{238}_{92}\mathrm{U} + \,^{66}_{30}\mathrm{Zn} \to \,^{304}_{122}\mathrm{Ubb} ^{*} \to \ no \ atoms


No atoms were detected and a yield limit of 5 mb (5,000,000 pb) was measured. Current results (see ununquadium) have shown that the sensitivity of this experiment was too low by at least 6 orders of magnitude.

In 2000, the Gesellschaft für Schwerionenforschung performed a very similar experiment with much higher sensitivity:


\,^{238}_{92}\mathrm{U} + \,^{70}_{30}\mathrm{Zn} \to \,^{308}_{122}\mathrm{Ubb} ^{*} \to \ no \ atoms


These results indicate that the synthesis of such heavier elements remains a significant challenge and further improvements of beam intensity and experimental efficiency is required. The sensitivity should be increased to 1 fb.

[edit] Possible discovery as a naturally occurring element

On April 24, 2008, a group led by Amnon Marinov at the Hebrew University of Jerusalem claimed to have found single atoms of unbibium in naturally occurring thorium deposits at an abundance of between 10-11 and 10-12, relative to thorium.[1] The claim of Marinov et al. was criticized by a part of the scientific community, and Marinov himself disclosed that Nature and Nature Physics had rejected his paper.[2]

[edit] See also

[edit] References

  1. ^ a b Marinov, A.; Rodushkin, I.; Kolb, D.; Pape, A.; Kashiv, Y.; Brandt, R.; Gentry, R. V.; Miller, H. W. (2008). "Evidence for a long-lived superheavy nucleus with atomic mass number A=292 and atomic number Z=~122 in natural Th". arXiv.org. 
  2. ^ Royal Society of Chemistry, Chemistry World, "Heaviest element claim criticised"

[edit] External links