Unbibium

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Unbibium (pronEng|ənˈbɪbiəm) or eka-thorium is the temporary name of a (purportedly) recently discoveredcite journal
last=Marinov | first=A.
coauthors=Rodushkin, I.; Kolb, D.; Pape, A.; Kashiv, Y.; Brandt, R.; Gentry, R. V.; Miller, H. W.
title=Evidence for a long-lived superheavy nucleus with atomic mass number A=292 and atomic number Z=~122 in natural Th
journal=arXiv.org | year=2008
url=http://arxiv.org/abs/0804.3869
accessdate=2008-04-28 ] chemical element in the periodic table that has the temporary symbol Ubb and has the atomic number 122.

History

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

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

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:

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

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.

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.The claim of Marinov et al. was criticized by a part of the scientific community, and Marinov says he has submitted the article to the journals "Nature" and "Nature Physics" but both turned it down without sending it for peer review.. [ Royal Society of Chemistry, [http://www.rsc.org/chemistryworld/News/2008/May/02050802.asp "Chemistry World", "Heaviest element claim criticised" ] ]

See also

*Island of stability
*Systematic element name
* Unbiunium – Unbitrium

References

External links

* [http://www.chemistry-blog.com/2008/04/29/adressing-marinovs-element-122-claim/ Chemistry-Blog: Independent analysis of Marinov’s 122 claim]
* [http://www.webelements.com/webelements/elements/text/Ubb/index.html WebElements.com - Unbibium]
* [http://www.apsidium.com/elements/122.htm Likely properties of Unbibium]
* [http://www.phys.huji.ac.il/~marinov/index.htm Marinov's Site]