Ununhexium

Ununhexium (pronounced /ˌjuːnənˈhɛksiəm/) is the temporary name of a synthetic superheavy element in the periodic table that has the temporary symbol Uuh and has the atomic number 116. Some research has referred to it as "eka-polonium".

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Discovery

In December, 2000 the Joint Institute for Nuclear Research (Dubna, Russia) published results^[1] that described the discovery in 2000 of decay of the isotope ²⁹²Uuh, which was produced in the reaction of ²⁴⁸Cm with ⁴⁸Ca (curium and calcium, elements 96 and 20, respectively). It has a half-life of about 18 milliseconds (0.018 seconds) and decayed into ²⁸⁸Uuq (ununquadium, element 114). On May 112001, the institute reported synthesizing a second atom, and that the properties confirmed a region of "enhanced" stability (see Island of stability).

In 2004 in the Joint Institute for Nuclear Research the synthesis of this element was confirmed by another method (the chemical identifying on final products of decay of element).

Further research

Ununhexium is a temporary IUPAC systematic element name.

In October, 2006 it was announced that on three occasions californium-249 atoms had been bombarded with calcium-48 ions to produce ununoctium (element 118), which decayed to ununhexium within a millisecond.^[2] If confirmed, the synthesis of element 116 will have been proven definitively.

The reaction that created ununhexium is:

This decayed 47 milliseconds later as follows to a previously identified isotope of element 114, Uuq.

History

In 1999, researchers at Lawrence Berkeley National Laboratory announced the discovery of elements 116 and 118 (ununhexium and ununoctium), in a paper published in Physical Review Letters.^[3] The following year, they published a retraction after other researchers were unable to duplicate the results.^[4] In June 2002, the director of the lab announced that the original claim of the discovery of these two elements had been based on data fabricated by the principal author Victor Ninov.

References

See also

• Island of stability