|
|
| General |
| Name, Symbol,
Number |
ununhexium, Uuh, 116 |
| Chemical series |
presumably poor metals |
| Group, Period,
Block |
16, 7, p |
| Standard atomic weight |
(302) g·mol−1 |
| Electron configuration |
perhaps [Rn] 5f14 6d10 7s2 7p4
(guess based on polonium) |
| Electrons per shell |
2, 8, 18, 32, 32, 18, 6 |
| CAS registry number |
54100-71-9 |
| Selected isotopes |
|
|
| References |
Ununhexium (IPA: /ˌjuːnʌnˈhɛksiəm/) 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".
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
External links
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