Ununpentium (pronEng|ˌjuːnənˈpɛntiəm or IPA|/ˌʌnənˈpɛntiəm/) is the temporary name of a synthetic
superheavy elementin the periodic tablethat has the temporary symbol Uup and has the atomic number115. Two isotopes are currently known, Uup-287 and Uup-288.
Element 115 also falls in the center of the theoretical
island of stability. The most stable isotope of ununpentium is predicted to be Uup-299, containing the theorized "magic number" of 184 neutrons. The most neutron rich isotope to date is Uup-288, which contains only 173 neutrons.
February 2, 2004, synthesis of ununpentium was reported in Physical ReviewC by a team composed of Russian scientists at the Joint Institute for Nuclear Researchin Dubna, and American scientists at the Lawrence Livermore National Laboratory. [ [http://link.aps.org/abstract/PRC/v69/e021601 "Experiments on the synthesis of element 115 in the reaction 243Am(48Ca,xn)291−x115"] , Oganessian et al., "Phys. Rev. C69", 021601 (2004). Retrieved on 2008-03-03] [ [http://www.jinr.ru/publish/Preprints/2003/178(E7-2003-178).pdf "Experiments on the synthesis of element 115 in the reaction 243Am(48Ca,xn)291−x115"] , Oganessian et al., "JINR preprints (2003)". Retrieved on 2008-03-03] The team reported that they bombarded americium-243 with calcium-48 ions to produce four atoms of ununpentium. These atoms, they report, decayed by emission of alpha-particles to ununtriumin approximately 100 milliseconds. :
The Dubna-Livermore collaboration has strengthened their claim for the discovery of ununpentium by conducting chemical experiments on the decay daughter 268Db. In experiments in June 2004 and December 2005, the Dubnium isotope was successfully identified by milking the Db fraction and measuring any SF activities. [ [http://www.jinr.ru/publish/Preprints/2004/157(e12-2004-157).pdf "RESULTS OF THE EXPERIMENT ON CHEMICAL IDENTIFICATION OF Db AS A DECAY PRODUCT OF ELEMENT 115"] , Oganessian et al., "JINR preprints (2004)". Retrieved on
2008-03-03] [ [http://link.aps.org/abstract/PRC/v72/e034611 "Synthesis of elements 115 and 113 in the reaction 243Am + 48Ca"] , Oganessian et al., "Phys. Rev. C72", 034611 (2005). Retrieved on 2008-03-03] Both the halflife and decay mode were confirmed for the proposed 268Db which lends support to the assignment of Z=115 to the parent nuclei.
Theoretical calculation in a quantum tunneling model supports the experimental alpha decay half lifes. citejournal| journal=Nucl. Phys. A|volume=789|pages=142–154|year=2007| title=Predictions of alpha decay half lives of heavy and superheavy elements|author=C. Samanta, P. Roy Chowdhury and D.N. Basu|url=http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVB-4NF4F0Y-2&_user=2806701&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000058844&_version=1&_urlVersion=0&_userid=2806701&md5=3f680654b5659191d67f31681a4cfc83| doi=10.1016/j.nuclphysa.2007.04.001]
The element with Z=115 is historically known as "eka-bismuth". "Ununpentium" (Uup) is a temporary
IUPAC systematic element name. Research scientists usually refer to the element simply as "element 115" (E115).
Proposed names by claimants
Claims to the discovery of element 115 have been put forward by Dmitriev of the Dubna team. The Joint Working Party will decide to whom the right to suggest a name will be given. The IUPAC have the final say on the official adoption of a name. The table below gives the names that the teams above have suggested and which can be verified by press interviews.
According to IUPAC rules, names used for previous elements that have ultimately not been adopted are not allowed to be proposed for future use.The table below summarises those names which are probably not allowed to be proposed by the claimant laboratories under the rules.
Yields of isotopes
The table below provides cross-sections and excitation energies for hot fusion reactions producing ununpentium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel.
The team at
RIKENare planning to study the reaction:
As a primary next-goal for the Dubna team, they are planning to examine to products of the 243Am + 48Ca using mass spectrometry in their state-of-the-art MASHA machine. They will attempt to isolate the
dubniumproducts, convert them chemically into a volatile compound, most likely 268DbCl5, and measure the mass directly.
In popular culture
Element 115 was first mentionedFact|date=February 2008 in the 1980s in association with UFO conspiracy theories. The most popular account of element 115 is from
Bob Lazar, who claims to have worked on a top-secret, alien craft reverse-engineeringprogram at a site known as S-4 near Groom Lake, Nevada. Many popular culture websites exist which discuss and critique the claims surrounding the element and the field. Bob Lazarclaims that Element 115 exists as a stable isotope. It's used as a fuel via nuclear reactions with proton projectiles in which antiprotons are created. These are then collected and channeled into an annihilation chamber where they react with protons to form gamma rays and lots of energy. This enormous power is used to fantastically multiply the minuscule Gravity-Awave also produced by the onboard Element 115 reactor. Gravity-Ais understood to exist only between atomic nuclear particles and is vastly more powerful than the Gravity-Bwith which we are all familiar from our own everyday experience. Element 115 is unusual in that the Gravity-A effect extends just beyond the perimeter of the Element 115 atom and with very advanced technology can be tapped and amplified and then directed via gravity distortion devices to produce a kind of "propulsive" effect for the alien spacecraft. What is supposedly happening is that the craft is creating a large enough space-time distortion along its direction of orientation that it essentially "falls downhill" through the artificially generated gravity corridor (while possibly eliminating outside gravity; besides, observed UFOs exhibit characteristics of some form of inertialess propulsion, capable of extreme accelerations and sharp turns without losing control; if the craft does indeed generate its own gravity field, it would explain these feats).
cience-based critique of claim
There is much debate regarding the possibility of a stable isotope of element 115. The element is expected to lie within the
island of stabilityand recent results have confirmed its existence (see ununquadium). The recent synthesis of two isotopes of ununpentium has been taken to suggest that the existence of a stable isotope is unlikely. However, many critics fail to appreciate the nature of closed magic shells. In particular, most people focus solely on the much-talked-about N=184 shell. It should be pointed out that this is not the only closed magic neutron shell. Calculations have indicated a closed deformed magic shell at N=196 and a spherical closed shell at N=228. [http://springerlink.com/content/d81588nlj591757x/ "Magic numbers of ultraheavy nuclei"] , Denisov, V.., "Phys. Atom Nucl.", 68, 7, 2005. Retrieved on 2008-03-03] [ [http://prola.aps.org/abstract/PRC/v6/i2/p591_1 "Superheavy Hartree-Fock Calculations"] , Saunier et al., "Phys. Rev. C.", 1972, 6, 591-595. Retrieved on 2008-03-03] These calculations in conjunction with expected trends [http://prola.aps.org/abstract/PRC/v56/i2/p812_1 "Properties of the hypothetical spherical superheavy nuclei"] , Smolanczuk, R., "Phys. Rev. C 56", 812-824 (1997). Retrieved on 2008-03-03] strongly imply that more stable isotopes of element 114 are possibly 310114 (N=196) and most likely 342114 (N=226). Taking hindrance of fission by odd particles into account, the most stable isotope of element 115 is probably 345115 and definitely not 299115. Such nuclei also have much more favourable N/Z values and lie closer to the classical stability line.298114 is in fact relatively neutron deficient for a Z=114 nucleus (N/Z 2.61 c.f. 2.60 for 244Pu) using a classical liquid-drop approach. Using the trends in Qalpha vs N from recent calculations, extrapolations indicate that Qalpha should fall on approach to the N=228 shell and Qalpha may reach a value of ~5.8 MeV for 342114. [see figure 4 in 9] This provides a halflife of 1.83x1010 years (using Viola-Seaborg equation) and can be taken to be 'stable', like uranium.
The claimed method of synthesis of the antiprotons is known from the study of cosmic rays. Interactions between protons and nuclei lead to the formation of so-called secondary
antiprotonswhich could be stored and used. The reaction would be inferred to be:see antiproton]
However this reaction does not work as a useful energy source: the energy "input" is "larger" than the energy "output" from the annihilation of the antiproton with another proton (approximately 1.8 GeV).
The study of the proton-antiproton annihilation reaction is well-known and is currently the subject of much research.
Levitation in materials is caused by
diamagneticproperties. Bismuthis known to be the strongest of all diamagnetic materials on Earth and hence element 115, as its heavier homolog, may well have even stronger diamagnetic attributes. Recent research on the synthesis of element 113has highlighted the effect of the structure of the bismuth nucleus on reactions and as such it should be prone to manipulation using electrorotation. These levitation effects though do not have anything to do with gravity manipulation, as they are purely electromagnetic in nature (diamagnetism is a form of magnetism, not gravity). There is no evidence that certain elements can have anomalous gravitational effects.
However, one rival theory of gravity is that it is also a type of electromagnetic wave, and is in fact the same as electromagnetism. See electrogravity.
Some of the claimed properties of element 115 may have some verification from mainstream science, either as hard experimental evidence or in modern theoretical calculations. Others are either lacking or are the result of simple misunderstanding as in the case of the erroneously attributed claims of
However, as was the case with newtonian physics and quantum mechanics, current physics knowledge may be incomplete in some areas and some of the claimed properties of a stable isotope of element 115 may indeed lend themselves to these effects, however, to date none of these effects have been observed by mainstream science. As such, they can not be considered to be true based on the available evidence.
This element was used as fuel for a
time machinein the Science fiction show "Seven Days". It is also the most desired resource in the " X-Com" series of tactical computer games, where it is given the name " Elerium-115".
Island of stability
* [http://radiochemistry.org/periodictable/elements/115.html Uut and Uup Add Their Atomic Mass to Periodic Table]
* [http://apsidium.com/elements/115.htm Apsidium: Ununpentium]
* [http://physicsweb.org/articles/world/17/7/7 Superheavy elements]
* [http://vanderkrogt.net/elements/elem/uup.html History and etymology]
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