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114 ununtriumununquadiumununpentium


Name, Symbol, Number ununquadium, Uuq, 114
Chemical series presumably poor metals
Group, Period, Block 14, 7, p
Appearance unknown, probably silvery
white or metallic gray
Standard atomic weight (298)  g·mol−1
Electron configuration perhaps [Rn] 5f14 6d10 7s2 7p2
(guess based on lead)
Phase presumably a solid
CAS registry number 54085-16-4
Selected isotopes
Main article: Isotopes of ununquadium
iso NA half-life DM DE (MeV) DP
288Uuq syn 2.8 s

Ununquadium (pronounced /juːnənˈkwɒdiəm/), or eka-lead, is the temporary name of a radioactive chemical element in the periodic table that has the temporary symbol Uuq and has the atomic number 114.



The discovery of ununquadium in December 1998 was reported in January 1999 by scientists at Dubna (Joint Institute for Nuclear Research) in Russia.[1] The same team produced another isotope of Uuq three months later[2] and confirmed the synthesis in 2004 and 2006.


Ununquadium is a temporary IUPAC systematic element name. Some have termed it eka-lead, as its properties are conjectured to be similar to those of lead. It is expected to be a soft, dense metal that tarnishes in air, with a melting point around 200 degrees Celsius.


Ununquadium can be synthesized by bombarding plutonium-242 and 244 targets with calcium-48 heavy ion beams, such as in

\,^{242}_{94}\mathrm{Pu} + \,^{48}_{20}\mathrm{Ca} \, \to \,^{287}_{114}\mathrm{Uuq} + 3 \; ^1_0\mathrm{n} \;

\,^{244}_{94}\mathrm{Pu} + \,^{48}_{20}\mathrm{Ca} \, \to \,^{289}_{114}\mathrm{Uuq} + 3 \; ^1_0\mathrm{n} \;

In search for the island of stability - ununquadium-298

According to the island of stability theory, some nuclides around the area of 114 protons and 184 neutrons (i.e. isotope Uuq-298) can be expected to be relatively stable in comparison to the surrounding nuclides. Ununquadium does not occur naturally, so it is entirely synthesized in laboratories. All isotopes of ununquadium synthesized so far are neutron-poor. This means that they contain significantly fewer neutrons than 184, which is one of the magic number of neutrons that is believed to make the isotope more stable. Neutron-poor also indicates that the isotopes decay either by spontaneous fission producing a variety of radionuclides, positron emission or electron capture to yield element ununtrium. So far, all three that have been made have undergone spontaneous fission in the first .0012 milliseconds, and therefore have never been able to be studied.

Difficulty in synthesis

Manufacturing ununquadium-298 would be very difficult, because nuclei summing to 114 protons and 184 neutrons are not available in weighable quantities.

However it may be possible to generate ununquadium-298, if nuclear transfer reactions can be achieved.[citation needed] One of these reactions may be

\,^{204}_{80}\mathrm{Hg} + \,^{136}_{54}\mathrm{Xe} \, \to \,^{298}_{114}\mathrm{Uuq} + \,^{40}_{20}\mathrm{Ca} + 2 \; ^1_0\mathrm{n} \;

See also


  1. ^ Oganessian, Yu. Ts.; et al. (October 1999). "Synthesis of Superheavy Nuclei in the 48Ca + 244Pu Reaction". Physical Review Letters 83: 3154. doi:10.1103/PhysRevLett.83.3154.
  2. ^ Oganessian; et al. (July 1999). "Synthesis of nuclei of the superheavy element 114 in reactions induced by 48Ca". Nature 400: 242. doi:10.1038/22281.
  • Report in Science
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Ununquadium". A list of authors is available in Wikipedia.