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Roentgenium is a synthetic radioactive chemical element with the symbol Rg and atomic number 111. It is placed as the heaviest member of the group 11 (IB) elements, although a sufficiently stable isotope has not yet been produced in a sufficient amount that would confirm this position as a heavier homologue of gold. Sony VAIO VGN-AW82DS Battery
Roentgenium was first observed in 1994 and several isotopes have been synthesized since its discovery. The most stable known isotope is 281Rg with a half-life of ~26 seconds,[2] which decays by spontaneous fission, like many other N=170 isotones. Sony VAIO VGN-AW82JS Battery
Official discovery
Roentgenium was officially discovered by an international team led by Sigurd Hofmann at the Gesellschaft für Schwerionenforschung(GSI) in Darmstadt, Germany, on December 8, 1994.[3] Only three atoms of it were observed (all 272Rg), by the cold fusion between nickel ions and a bismuth target in a linear accelerator: Sony VAIO VGN-AW82YS Battery
In 2001, the IUPAC/IUPAP Joint Working Party (JWP) concluded that there was insufficient evidence for the discovery at that time.[4] The GSI team repeated their experiment in 2002 and detected three more atoms.[5][6] In their 2003 report, the JWP decided that the GSI team should be acknowledged for the discovery of this element.[7] Sony VAIO VGN-AW83FS Battery,Sony VAIO VGN-AW83GS Battery
Naming
The name roentgenium (Rg) was recommended by the GSI team[8] in honor of the German physicist Wilhelm Conrad Röntgen in 2004.[9] This name was accepted by IUPAC on November 1, 2004 and approved by IUPAP on November 4, 2011.[10] Previously the element was known under the temporary IUPAC systematic element name unununium, Uuu. Sony VAIO VGN-AW83HS Battery
Target-projectile combinations leading to Z=111 compound nuclei
The below table contains various combinations of targets and projectiles (both at max no. of neutrons) which could be used to form compound nuclei with Z=111. Sony VAIO VGN-AW90S Battery
Cold fusion
This section deals with the synthesis of nuclei of roentgenium by so-called “cold” fusion reactions. These are processes which create compound nuclei at low excitation energy (~10–20 MeV, hence “cold”), leading to a higher probability of survival from fission. The excited nucleus then decays to the ground state via the emission of one or two neutrons only. Sony VAIO VGN-AW91CDS Battery,Sony VAIO VGN-AW91CJS Battery,Sony VAIO VGN-AW91CYS Battery
209Bi(64Ni,xn)273?xRg (x=1)
First experiments to synthesize roentgenium were performed by the Dubna team in 1986 using this cold fusion reaction. No atoms were identified that could be assigned to atoms of roentgenium and a production cross-section limit of 4 pb was determined. Sony VAIO VGN-AW91DS Battery,Sony VAIO VGN-AW91JS Battery
After an upgrade of their facilities, the team at GSI successfully detected 3 atoms of 272Rg in their discovery experiment.[3] A further 3 atoms were synthesized in 2000.[5] The discovery of roentgenium was confirmed in 2003 when a team atRIKEN measured the decays of 14 atoms of 272Rg during the measurement of the 1n excitation function.[11] Sony VAIO VGN-AW91YS Battery,Sony VAIO VGN-AW92CDS Battery
208Pb(65Cu,xn)273?xRg (x=1)
In 2004, as part of their study of odd-Z projectiles in cold fusion reactions, the team at LBNL detected a single atom of 272Rg in this new reaction.[12][13] Sony VAIO VGN-AW92CJS Battery
As a decay product
Isotopes of roentgenium have also been observed in the decay of heavier elements. Observations to date are outlined in the table below: Sony VAIO VGN-AW92CYS Battery
274Rg
Two atoms of 274Rg have been observed in the decay chains starting with 278Uut. The two events occur with different energies and with different lifetimes. In addition, the two entire decay chains appear to be different. This suggests the presence of two isomeric levels but further research is required. Sony VAIO VGN-AW92DS Battery
272Rg
The direct production of 272Rg has provided four alpha lines at 11.37, 11.03, 10.82, and 10.40 MeV. The GSI measured a half-life of 1.6 ms whilst recent data from RIKEN have given a half-life of 3.8 ms. The conflicting data may be due to isomeric levels but the current data are insufficient to come to any firm assignments. Sony VAIO VGN-AW92YS Battery,Sony VAIO VGN-AW93FS Battery
Cold fusion
The table below provides cross-sections and excitation energies for cold fusion reactions producing roentgenium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel. Sony VAIO VGN-AW93GS Battery,Sony VAIO VGN-AW93HS Battery
Electronic structure (relativistic)
The stable group 11 elements, copper, silver, and gold all have an outer electron configuration nd10(n+1)s1. For each of these elements, the first excited state of their atoms has a configuration nd9(n+1)s2. Sony VAIO VGN-AW93ZFS Battery
Due to spin-orbit coupling between the d electrons, this state is split into a pair of energy levels. For copper, the difference in energy between the ground state and lowest excited state causes the metal to appear reddish. For silver, the energy gap widens and it becomes silvery. Sony VAIO VGN-AW93ZHS Battery
However, as Z increases, the excited levels are stabilized by relativistic effects and in gold the energy gap decreases again and it appears gold. For roentgenium, calculations indicate that the 6d97s2 level is stabilized to such an extent that it becomes the ground state. The resulting energy difference between the new ground state and the first excited state is similar to that of silver and roentgenium is expected to be silvery in appearance.[16] Sony VAIO VGN-BZ11EN Battery,Sony VAIO VGN-BZ11MN Battery
Oxidation states
Roentgenium is projected to be the ninth member of the 6d series of transition metals and the heaviest member of group 11 (IB) in the Periodic Table, below copper,silver, and gold. Each of the members of this group show different stable states. Copper forms a stable +2 state, while silver is predominantly found as silver(I) and gold as gold(I) or gold(III). Sony VAIO VGN-BZ11XN Battery,Sony VAIO VGN-BZ12VN Battery
Copper(I) and silver(II) are also relatively well-known. Roentgenium is therefore expected to predominantly form a stable +3 state. Gold also forms a somewhat stable -1 state due to relativistic effects, and roentgenium may do so as well.
Chemistry
The heavier members of this group are well known for their lack of reactivity or noble character. Sony VAIO VGN-BZ12XN Battery,Sony VAIO VGN-BZ31VT Battery
Silver and gold are both inertto oxygen, but are attacked by thehalogens. In addition, silver is attacked by sulfur and hydrogen sulfide, highlighting its higher reactivity compared to gold. Roentgenium is expected to be even more noble than gold and can be expected to be inert to oxygen and halogens. The most-likely reaction is with fluorine to form a trifluoride, RgF3. Sony VAIO VGN-BZ31XT Battery,Sony VAIO VGN-BZ560 Battery
Copernicium is a chemical element with symbol Cn and atomic number 112. It is an extremely radioactive synthetic element that can only be created in a laboratory. The most stable known isotope, copernicium-285, has a half-life of approximately 29 seconds, but it is possible that this copernicium isotope may have an isomer with a longer half-life, 8.9 min. Sony VAIO VGN-BZ560N24 Battery,Sony VAIO VGN-BZ560N30 Battery
It was first created in 1996 by the Gesellschaft für Schwerionenforschung(GSI; Centre for Heavy Ion Research). It is named after the astronomer Nicolaus Copernicus.
In the periodic table of the elements, it is a d-block element, which belongs to transactinide elements. Sony VAIO VGN-BZ560P Battery,Sony VAIO VGN-BZ560P20 Battery
During reactions with gold, it is shown[2] to be a volatile metal and a group 12 element. Copernicium is calculated to have several properties that differ between it and its lighter homologues, zinc, cadmium and mercury; the most notable of them is withdrawing two 6d-electrons before 7s ones due to relativistic effects, which confirm copernicium as an undisputed transition metal. Sony VAIO VGN-BZ560P22 Battery,Sony VAIO VGN-BZ560P28 Battery
Copernicium is also calculated to show predominance of oxidation state +4, while mercury shows it in only one compound at extreme conditions and zinc and cadmium do not show it at all. Difficulty of oxidation of copernicium from its neutral state compared to group 12 elements has also been predicted. Sony VAIO VGN-BZ560P30 Battery
Sony VAIO VGN-BZ560P34 Battery
In total, approximately 75 atoms of copernicium have been detected using various nuclear reactions.
Official discovery
Copernicium was first created on February 9, 1996, at the Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, Germany, by Sigurd Hofmann, Victor Ninov et al.[3] Sony VAIO VGN-BZ561 Battery
Sony VAIO VGN-BZ561N20 Battery
This element was created by firing accelerated zinc-70 nuclei at a target made of lead-208 nuclei in a heavy ion accelerator. A single atom (the second was subsequently dismissed) of copernicium was produced with a mass number of 277.[3] Sony VAIO VGN-BZ561P20 Battery
In May 2000, the GSI successfully repeated the experiment to synthesize a further atom of copernicium-277.[4][5] This reaction was repeated at RIKEN using the Search for a Super-Heavy Element Using a Gas-Filled Recoil Separator set-up in 2004 to synthesize two further atoms and confirm the decay data reported by the GSI team.[6] Sony VAIO VGN-BZ562P Battery,Sony VAIO VGN-BZ563P Battery
The IUPAC/IUPAP Joint Working Party (JWP) assessed the claim of discovery by the GSI team in 2001[7] and 2003.[8] In both cases, they found that there was insufficient evidence to support their claim. This was primarily related to the contradicting decay data for the known nuclide rutherfordium-261. Sony VAIO VGN-BZAAFS Battery,Sony VAIO VGN-BZAAHS Battery
However, between 2001 and 2005, the GSI team studied the reaction 248Cm(26Mg,5n)269Hs, and were able to confirm the decay data for hassium-269 and rutherfordium-261. It was found that the existing data on rutherfordium-261 was for an isomer,[9] now designated rutherfordium-261a. Sony VAIO VGN-BZAANS Battery,Sony VAIO VGN-BZAAPS Battery
In May 2009, the JWP reported on the claims of discovery of element 112 again and officially recognized the GSI team as the discoverers of element 112.[10] This decision was based on the confirmation of the decay properties of daughter nuclei as well as the confirmatory experiments at RIKEN.[11] Sony VAIO VGN-CR11H/B Battery,Sony VAIO VGN-CR11S/L Battery
Naming
Copernicium was named after Nicolaus Copernicus, a scientist who showed that the Earth moves around the Sun, and not the other way round.
After acknowledging their discovery, the IUPAC asked the discovery team at GSI to suggest a permanent name for ununbium.[12][13] Sony VAIO VGN-CR11S/P Battery,Sony VAIO VGN-CR11S/W Battery
On 14 July 2009, they proposed copernicium with the element symbol Cp, after Nicolaus Copernicus ”to honor an outstanding scientist, who changed our view of the world.”[14] IUPAC delayed the official recognition of the name, pending the results of a six-month discussion period among the scientific community. Sony VAIO VGN-CR11Z/R Battery,Sony VAIO VGN-CR120E/L Battery
However, it was pointed out that the symbol Cp was previously associated with the name cassiopeium (cassiopium), now known aslutetium (Lu).[17][18] Furthermore, the symbol Cp is also used in organometallic chemistry to denote the cyclopentadienyl ligand.Sony VAIO VGN-CR120E/P Battery,Sony VAIO VGN-CR120E/R Battery
For this reason, the IUPAC disallowed the use of Cp as a future symbol, prompting the GSI team to put forward the symbol Cn as an alternative. On 19 February 2010, the 537th anniversary of Copernicus’ birth, IUPAC officially accepted the proposed name and symbol.[15][19] Sony VAIO VGN-CR120E/W Battery,Sony VAIO VGN-CR125E/B Battery
The name was also approved by the General Assembly of the International Union of Pure and Applied Physics (IUPAP) on November 4, 2011.[20]
Nucleosynthesis
Super-heavy elements such as copernicium are produced by bombarding lighter elements in particle accelerators that induces fusion reactions. Sony VAIO VGN-CR13/B Battery,Sony VAIO VGN-CR13/L Battery
Whereas most of the isotopes of rutherfordium can be synthesized directly this way, some heavier ones have only been observed as decay products of elements with higher atomic numbers.[21]
Depending on the energies involved, the former are separated into “hot” and “cold”. Sony VAIO VGN-CR13/P Battery,Sony VAIO VGN-CR13/R Battery
In hot fusion reactions, very light, high-energy projectiles are accelerated toward very heavy targets such as actinides, giving rise to compound nuclei at high excitation energy (~40–50 MeV) that may either fission or evaporate several (3 to 5) neutrons.[21] In cold fusion reactions, the produced fused nuclei have a relatively low excitation energy (~10–20 MeV), which decreases the probability that these products will undergo fission reactions. Sony VAIO VGN-CR13/W Battery,Sony VAIO VGN-CR131E/L Battery
As the fused nuclei cool to the ground state, they require emission of only one or two neutrons, and thus, allows for the generation of more neutron-rich products.[22] The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion).[23] Sony VAIO VGN-CR13G Battery,Sony VAIO VGN-CR13G/B Battery
Cold fusion
The first cold fusion reaction to produce copernicium was performed by GSI in 1996, who reported the detection of two decay chains of copernicium-277.[3]
In a review of the data in 2000, the first decay chain was retracted. In a repeat of the reaction in 2000 they were able to synthesize a further atom. Sony VAIO VGN-CR13G/L Battery,Sony VAIO VGN-CR13G/P Battery
They attempted to measure the 1n excitation function in 2002 but suffered from a failure of the zinc-70 beam. The unofficial discovery of copernicium-277 was confirmed in 2004 atRIKEN, where researchers detected a further two atoms of the isotope and were able to confirm the decay data for the entire chain.[6] Sony VAIO VGN-CR13G/W Battery,Sony VAIO VGN-CR13T/L Battery
After the successful synthesis of copernicium-277, the GSI team performed a reaction using a 68Zn projectile in 1997 in an effort to study the effect of isospin(neutron richness) on the chemical yield. Sony VAIO VGN-CR13T/P Battery
The experiment was initiated after the discovery of a yield enhancement during the synthesis of darmstadtium isotopes using nickel-62 and nickel-64 ions. No decay chains of copernicium-275 were detected leading to a cross section limit of 1.2 picobarns (pb). However, the revision of the yield for the zinc-70 reaction to 0.5 pb does not rule out a similar yield for this reaction. Sony VAIO VGN-CR13T/R Battery,Sony VAIO VGN-CR13T/W Battery
In 1990, after some early indications for the formation of isotopes of copernicium in the irradiation of a tungsten target with multi-GeV protons, a collaboration between GSI and the University of Jerusalem studied the foregoing reaction. Sony VAIO VGN-CR15/B Battery,Sony VAIO VGN-CR150E/B Battery
They were able to detect some spontaneous fission (SF) activity and a 12.5 MeV alpha decay, both of which they tentatively assigned to the radiative capture product copernicium-272 or the 1n evaporation residue copernicium-271. Both the TWG and JWP have concluded that a lot more research is required to confirm these conclusions.[21] Sony VAIO VGN-CR190 Battery,Sony VAIO VGN-CR190E/L Battery
Hot fusion
In 1998, the team at the Flerov Laboratory of Nuclear Research (FLNR) in Dubna, Russia began a research program using calcium-48 nuclei in “warm” fusion reactions leading to super-heavy elements. In March 1998, they claimed to have synthesized two atoms of the element in the following reaction. Sony VAIO VGN-CR190E/P Battery,Sony VAIO VGN-CR190E/R Battery
The long half-life of the product initiated first chemical experiments on the gas phase atomic chemistry of copernicium. In 2000, Yuri Yukashev in Dubna repeated the experiment but was unable to observe any spontaneous fission with half-life of 5 minutes. Sony VAIO VGN-CR190E/W Battery
The experiment was repeated in 2001 and an accumulation of eight fragments resulting from spontaneous fission were found in the low-temperature section, indicating that copernicium had radon-like properties. However, there is now some serious doubt about the origin of these results. To confirm the synthesis, the reaction was successfully repeated by the same team in January 2003, confirming the decay mode and half-life. Sony VAIO VGN-CR19VN/B Battery,Sony VAIO VGN-CR19XN/B Battery
They were also able to calculate an estimate of the mass of the spontaneous fission activity to ~285, lending support to the assignment.[25]
The team at Lawrence Berkeley National Laboratory (LBNL) in Berkeley, United States entered the debate and performed the reaction in 2002. Sony VAIO VGN-CR20 Battery,Sony VAIO VGN-CR21/B Battery
They were unable to detect any spontaneous fission and calculated a cross section limit of 1.6 pb for the detection of a single event.[26]
The reaction was repeated in 2003–2004 by the team at Dubna using a slightly different set-up, the Dubna Gas-Filled Recoil Separator (DGFRS). Sony VAIO VGN-CR21E/L Battery,Sony VAIO VGN-CR21E/P Battery
This time, copernicium-283 was found to decay by emission of a 9.53 MeV alpha-particle with a half-life of 4 seconds. copernicium-282 was also observed in the 4n channel (emitting 4 neutrons).[27]
In 2003, the team at GSI entered the debate and performed a search for the five-minute SF activity in chemical experiments. Sony VAIO VGN-CR21E/W Battery,Sony VAIO VGN-CR21S/L Battery
Like the Dubna team, they were able to detect seven SF fragments in the low temperature section. However, these SF events were uncorrelated, suggesting they were not from actual direct SF of copernicium nuclei and raised doubts about the original indications for radon-like properties.[28] Sony VAIO VGN-CR21S/P Battery,Sony VAIO VGN-CR21S/W Battery
After the announcement from Dubna of different decay properties for copernicium-283, the GSI team repeated the experiment in September 2004. They were unable to detect any SF events and calculated a cross section limit of ~1.6 pb for the detection of one event, not in contradiction with the reported 2.5 pb yield by Dubna. Sony VAIO VGN-CR21Z/N Battery,Sony VAIO VGN-CR21Z/R Battery
In May 2005, the GSI performed a physical experiment and identified a single atom of 283Cn decaying by SF with a short half-time suggesting a previously unknown SF branch.[29] However, initial work by Dubna had detected several direct SF events but had assumed that the parent alpha decay had been missed. These results indicated that this was not the case. Sony VAIO VGN-CR220E/R Battery,Sony VAIO VGN-CR23/B Battery
The new decay data on copernicium-283 were confirmed in 2006 by a joint PSI-FLNR experiment aimed at probing the chemical properties of copernicium. Two atoms of copernicium-283 were observed in the decay of the parent ununquadium-287 nuclei. The experiment indicated that contrary to previous experiments, copernicium behaves as a typical member of group 12, demonstrating properties of a volatile metal.[2] Sony VAIO VGN-CR23/L Battery,Sony VAIO VGN-CR23/N Battery
Finally, the team at GSI successfully repeated their physical experiment in January 2007, and detected three atoms of copernicium-283, confirming both the alpha and SF decay modes.[30]
As such, the 5 minutes SF activity is still unconfirmed and unidentified. It is possible that it refers to an isomer, namely copernicium-283b, whose yield is dependent upon the exact production methods. Sony VAIO VGN-CR23/P Battery,Sony VAIO VGN-CR23/R Battery,Sony VAIO VGN-CR23/W Battery
The team at FLNR studied this reaction in 2004. They were unable to detect any atoms of copernicium and calculated a cross section limit of 0.6 pb. The team concluded that this indicated that the neutron mass number for the compound nucleus had an effect on the yield of evaporation residues.[27] Sony VAIO VGN-CR240E/B Battery,Sony VAIO VGN-CR240N/B Battery
Decay products
Copernicium has been observed as decay products of ununquadium. Ununquadium currently has five known isotopes, all of which have been shown to undergo alpha decays to become copernicium nuclei, with mass numbers between 281 and 285. Sony VAIO VGN-CR25G/N Battery.Sony VAIO VGN-CR290EAL Battery
Copernicium isotopes with mass numbers 281, 284 and 285 to date have only been produced by ununquadium nuclei decay. Parent ununquadium nuclei can be themselves decay products ofununhexium or ununoctium. To date, no other elements have been known to decay to copernicium.[35] Sony VAIO VGN-CR290EAN Battery,Sony VAIO VGN-CR290EAP Battery
For example, in May 2006, the Dubna team (JINR) identified copernicium-282 as a final product in the decay of ununoctium via the alpha decay sequence. It was found that the final nucleus undergoes spontaneous fission.[32] Sony VAIO VGN-CR290EAR Battery
In the claimed synthesis of ununoctium-293 in 1999, copernicium-281 was identified as decaying by emission of a 10.68 MeV alpha particle with half-life 0.90 ms.[36]The claim was retracted in 2001. This isotope was finally created in 2010 and its decay properties supported that the previous data was wrong.[31] Sony VAIO VGN-CR290EAW Battery,Sony VAIO VGN-CR29XN/B Battery
Copernicium has no stable or naturally-occurring isotopes. Several radioactive isotopes have been synthesized in the laboratory, either by fusing two atoms or by observing the decay of heavier elements. Six different isotopes have been reported with atomic masses from 281 to 285, and 277, two of which, copernicium-283 and copernicium-285, have known metastable states. Sony VAIO VGN-CR305E/RC Battery,Sony VAIO VGN-CR31S/D Battery
Most of these decay predominantly through alpha decay, but some undergo spontaneous fission.[35]
Half-lives
All copernicium isotopes are extremely unstable and radioactive; in general, heavier isotopes are more stable than the lighter. Sony VAIO VGN-CR323/W Battery
The most stable isotope, copernicium-285, has a half-life of 29 seconds, although it is suspected that this isotope has an isomer with a half-life of 8.9 minutes, and copernicium-283 may have an isomer with a half-life of about 5 minutes. Other isotopes have half-lives shorter than 0.1 seconds. Sony VAIO VGN-CR382 Battery
Sony VAIO VGN-CR490EBL Battery
Copernicium-281 and copernicium-284 have half-life of 97 ms, and the other two isotopes have half-lives slightly under one millisecond.[35]
The lightest isotopes were synthesized by direct fusion between two lighter nuclei and as decay products (except for copernicium-277, which is known to be a decay product), while the heavier isotopes are only known to be produced by decay of heavier nuclei.Sony VAIO VGN-CR490EBN Battery,Sony VAIO VGN-CR490EBP Battery
The heaviest isotope produced by direct fusion is copernicium-283; the two heavier isotopes, copernicium-284 and copernicium-285 have only been observed as decay products of elements with larger atomic numbers.[35] In 1999, American scientists at the University of California, Berkeley, announced that they had succeeded in synthesizing three atoms of 293118.[37] Sony VAIO VGN-CR490EBR Battery
Sony VAIO VGN-CR490EBT Battery
These parent nuclei were reported to have successively emitted three alpha particles to form copernicium-281 nuclei, which were claimed to have undergone an alpha decay, emitting an alpha particle with decay energy of 10.68 MeV and half-life 0.90 ms, but their claim was retracted in 2001.[38] Sony VAIO VGN-CR490EBW Battery
The isotope, however, was produced in 2010 by the same team, confirming the previous data was wrong.[31]
Nuclear isomerism
First experiments on the synthesis of 283Cn produced a SF activity with half-life ~5 min.[35] This activity was also observed from the alpha decay of ununquadium-287. Sony VAIO VGN-CR51B/W Battery,Sony VAIO VGN-CR520E/J Battery
The decay mode and half-life were also confirmed in a repetition of the first experiment. Later, copernicium-283 was observed to undergo 9.52 MeV alpha decay and SF with a half-life of 3.9 s. It has also been found that alpha decay of copernicium-283 leads to different excited states of darmstadtium-279.[39] Sony VAIO VGN-CR52B/W Battery,Sony VAIO VGN-CR590EBL Battery
These results suggest the assignment of the two activities to two different isomeric levels in copernicium-283, creating copernicium-283a and copernicium-283b.
Copernicium-285 has only been observed as a decay product of ununquadium-289 and ununhexium-293; Sony VAIO VGN-CR590EBN Battery
Sony VAIO VGN-CR590EBP Battery
during the first recorded synthesis of ununquadium, one ununquadium-289 was created, which alpha decayed to copernicium-285, which itself emitted an alpha particle in 29 seconds, releasing 9.15 or 9.03 MeV.[27] However, the first successful experiment of ununhexium synthesis, Sony VAIO VGN-CR590EBR Battery
Sony VAIO VGN-CR590EBT Battery
when ununhexium-293 was created, it was shown that the created nuclide alpha decayed to ununquadium-289, decay data for which differed from the known values significantly. Although unconfirmed, it is highly possible that this is associated with an isomer. Sony VAIO VGN-CR590EBW Battery
The resulting nuclide decayed to copernicium-285, which emitted an alpha article with a half-life of 8.9 minutes, releasing 8.63 MeV. Similar to its parent, it is believed to be a nuclear isomer, namely copernicium-285b.[40] Sony VAIO VGN-CR60B/P Battery
Extrapolated oxidation states
Copernicium is the last member of the 6d series of transition metals and the heaviest group 12 element in the periodic table, below zinc, cadmium and mercury. It is predicted to differ significantly from lighter group 12 elements. Sony VAIO VGN-CR60B/R Battery,Sony VAIO VGN-CR61B/L Battery
Due to stabilization of 7s electronic orbitals and destabilization of 6d ones caused byrelativistic effects, Cn2+ is likely to have a [Rn]5f146d87s2 electronic configuration, breaking 6d orbitals before 7s one, unlike its homologues. In water solutions, copernicium is likely to form +2 and +4 oxidation states, with the latter one being more stable.[41] Sony VAIO VGN-CR61B/N Battery
Among lighter group 12 members, for which the +2 oxidation state is the most common, only mercury can show +4 oxidation state, but it is highly uncommon, existing at only one compound (mercury(IV) fluoride, HgF4) at extreme conditions.[42] The analogous compound for copernicium, CnF4, is predicted to be more stable.[41] Sony VAIO VGN-CR61B/R Battery
The diatomic ion Hg2+
2, featuring mercury in +1 oxidation state is well-known, but the Cn2+
2 ion is predicted to be unstable or even non-existent.[41] Oxidation of copernicium from its neutral state is also likely to be harder than those of previous group 12 members.[41] Sony VAIO VGN-CR62B/N Battery
Experimental atomic gas phase chemistry
Copernicium has the ground state electron configuration [Rn]5f146d107s2 and thus should belong to group 12 of the periodic table, according to Aufbau principle. As such, it should behave as the heavier homologue of mercury and form strong binary compounds with noble metals like gold. Sony VAIO VGN-CR62B/R Battery
Experiments probing the reactivity of copernicium have focused on the adsorption of atoms of element 112 onto a gold surface held at varying temperatures, in order to calculate an adsorption enthalpy. Due to relativistic stabilization of the 7s electrons, copernicium shows radon-like properties. Sony VAIO VGN-CR71B/W Battery
Experiments were performed with the simultaneous formation of mercury and radon radioisotopes, allowing a comparison of adsorption characteristics.[43]
The first experiments were conducted using the 238U(48Ca,3n)283Cn reaction. Detection was by spontaneous fission of the claimed parent isotope with half-life of 5 minutes. Sony VAIO VGN-CR90HS Battery
Analysis of the data indicated that copernicium was more volatile than mercury and had noble gas properties. However, the confusion regarding the synthesis of copernicium-283 has cast some doubt on these experimental results. Given this uncertainty, between April–May 2006 at the JINR, a FLNR-PSI team conducted experiments probing the synthesis of this isotope as a daughter in the nuclear reaction 242Pu(48Ca,3n)287Uuq. Sony VAIO VGN-CR90S Battery
In this experiment, two atoms of copernicium-283 were unambiguously identified and the adsorption properties indicated that copernicium is a more volatile homologue of mercury, due to formation of a weak metal-metal bond with gold, placing it firmly in group 12.[43] Sony VAIO VGN-CR92NS Battery
In April 2007, this experiment was repeated and a further three atoms of copernicium-283 were positively identified. The adsorption property was confirmed and indicated that copernicium has adsorption properties completely in agreement with being the heaviest member of group 12. Sony VAIO VGN-CS118E/Q Battery
Sony VAIO VGN-CS118E/R Battery
Ununtrium is the temporary name of a synthetic element with the temporary symbol Uut and atomic number 113.
It is placed as the heaviest member of the group 13 (IIIA) elements although a sufficiently stable isotope is not known at this time that would allow chemical experiments to confirm its position. Sony VAIO VGN-CS118E/W Battery
It was first detected in 2003 in the decay ofununpentium and was synthesized directly in 2004. Only fourteen atoms of ununtrium have been observed to date. The longest-lived isotope known is 286Uut with a half-life of ~20 s,[1] allowing first chemical experiments to study its chemistry. Sony VAIO VGN-CS11S/Q Battery
Discovery profile
The first report of ununtrium was in August 2003 when it was identified as a decay product of ununpentium. These results were published on February 1, 2004, by a team composed of Russian scientists at Dubna (Joint Institute for Nuclear Research), and American scientists at the Lawrence Livermore National Laboratory.[2][3] Sony VAIO VGN-CS11Z/R Battery,Sony VAIO VGN-CS120J/P Battery
On July 23, 2004, a team of Japanese scientists at RIKEN detected a single atom of 278Uut using the cold fusion reaction between bismuth-209 and zinc-70. They published their results on September 28, 2004.[4] Sony VAIO VGN-CS120J/Q Battery
Support for their claim appeared in 2004 when scientists at the Institute of Modern Physics (IMP) identified 266Bh as decaying with identical properties to their single event (see bohrium).
The RIKEN team produced a further atom on April 2, 2005, although the decay data were different from the first chain, and may be due to the formation of a meta-stable isomer. Sony VAIO VGN-CS120J/R Battery
Sony VAIO VGN-CS190JTB Battery
The Dubna-Livermore collaboration has strengthened their claim for the discovery of ununtrium 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. Sony VAIO VGN-CS190JTP Battery,Sony VAIO VGN-CS190JTQ Battery
Both the half-life and decay mode were confirmed for the proposed 268Db which lends support to the assignment of Z=115 and Z=113 to the parent and daughter nuclei.[5][6]
Theoretical estimates of alpha-decay half-lives of alpha-decay chains from element 113 are in good agreement with the experimental data.[7] Sony VAIO VGN-CS190JTR Battery
Sony VAIO VGN-CS190JTW Battery
Recent experiments at Dubna have fully confirmed the data for ununpentium and ununtrium but have yet to be fully published and reviewed by the JWP. This process is likely not to occur for some time.
Sony VAIO VGN-CS190NAB Battery
Naming
The element with atomic number 113 is historically known as eka-thallium. Ununtrium (Uut) is a temporary IUPAC systematic element name. Research scientists usually refer to the element simply as element 113 (or E113). Sony VAIO VGN-CS190NAC Battery,Sony VAIO VGN-CS190NAD Battery
Proposed names by claimants
Claims to the discovery of ununtrium have been put forward by Dmitriev of the Dubna team and Morita of the RIKEN team. The IUPAC/IUPAP Joint Working Party will decide to whom the right to suggest a name will be given. Sony VAIO VGN-CS190NBB Battery,Sony VAIO VGN-CS190NCA Battery
In 2011, the IUPAC has evaluated the 2004 RIKEN experiments and 2004 and 2007 Dubna experiments, and concluded that they did not meet the criteria for discovery.[8]
The following names have been suggested by the above-mentioned teams claiming discovery: Sony VAIO VGN-CS190NCB Battery,Sony VAIO VGN-CS190NCC Battery
Target-projectile combinations leading to Z=113 compound nuclei
The below table contains various combinations of targets and projectiles (both at max no. of neutrons) which could be used to form compound nuclei with an atomic number of 113. Sony VAIO VGN-CS50B/W Battery
Cold fusion
This section deals with the synthesis of nuclei of ununtrium by so-called “cold” fusion reactions. These are processes which create compound nuclei at low excitation energy (~10–20 MeV, hence “cold”), leading to a higher probability of survival from fission. The excited nucleus then decays to the ground state via the emission of one or two neutrons only. Sony VAIO VGN-CS51B/W Battery
Sony VAIO VGN-CS52JB/W Battery
209Bi(70Zn,xn)279-xUut (x=1)
The synthesis of ununtrium was first attempted in 1998 by the team at GSI using the above cold fusion reaction. In two separate runs, they were unable to detect any atoms and calculated a cross section limit of 900 fb.[10] They repeated the experiment in 2003 and lowered the limit further to 400 fb.[10] Sony VAIO VGN-CS60B/P Battery
In late 2003, the emerging team at RIKEN using their efficient apparatus GARIS attempted the reaction and reached a limit of 140 fb. In December 2003 – August 2004, they resorted to ‘brute force’ and performed an eight-month-long irradiation in which they increased the sensitivity to 51 fb. They were able to detect a single atom of 278Uut.[4] Sony VAIO VGN-CS60B/R Battery
They repeated the reaction in several runs in 2005 and were able to synthesize a second atom. They calculated a record-low 31 fb for the cross section for the 2 atoms. The reaction was repeated again in 2006 with two long production runs but no further atoms were detected. This lowered the yield further to the current value of just 23 fb. Sony VAIO VGN-CS61B/Q Battery
Hot fusion
This section deals with the synthesis of nuclei of ununtrium by so-called “hot” fusion reactions. These are processes which create compound nuclei at high excitation energy (~40–50 MeV, hence “hot”), leading to a reduced probability of survival from fission.Sony VAIO VGN-CS62JB/P Battery
Sony VAIO VGN-CS62JB/Q Battery
The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing 48Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as “warm” fusion reactions. This leads, in part, to relatively high yields from these reactions. Sony VAIO VGN-CS62JB/R Battery,Sony VAIO VGN-CS71B/W Battery
237Np(48Ca,xn)285-xUut (x=3)
In June 2006, the Dubna-Livermore team synthesised ununtrium directly in the “warm” fusion reaction between neptunium-237 and calcium-48 nuclei. Two atoms of 282Uut were detected with a cross section of 900 fb.[11] Sony VAIO VGN-CS72JB/W Battery
Cold fusion
The table below provides cross-sections and excitation energies for cold fusion reactions producing ununtrium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel. Sony VAIO VGN-CS90NS Battery
Hot fusion
The table below provides cross-sections and excitation energies for hot fusion reactions producing ununtrium isotopes directly. Data in bold represents maxima derived from excitation function measurements. + represents an observed exit channel. Sony VAIO VGN-CS91HS Battery,Sony VAIO VGN-CS91NS Battery
Evaporation residue cross sections
The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given. Sony VAIO VGN-CS91S Battery,Sony VAIO VGN-CS92DS Battery
DNS = Di-nuclear system; ? = cross section
Oxidation states
Ununtrium is projected to be the first member of the 7p series of elements and the heaviest member of group 13 (IIIA) in the Periodic Table, below thallium. Each of the members of this group show the group oxidation state of +III. Sony VAIO VGN-CS92JS Battery
However, thallium has a tendency to form only a stable +I state due to the “inert pair effect”, explained by the relativistic stabilisation of the 7s-orbitals, resulting in a higher ionisation potential and weaker tendency to participate in bonding. Sony VAIO VGN-FW11E Battery
Chemistry
Ununtrium should portray eka-thallium chemical properties and should therefore form a monoxide, Uut2O, and monohalides, UutF, UutCl, UutBr, and UutI. If the +III state is accessible, it is likely that it is only possible in the oxide, Uut2O3, and fluoride, UutF3. Spin-orbit splitting of the 7p orbitals may stabilize the ?1 state as well, as is seen with gold(?1) (aurides). Sony VAIO VGN-FW11L Battery
Ununquadium is the temporary name of a radioactive chemical element with the temporary symbol Uuq and atomic number 114. As of December 1, 2011, the name flerovium (after Soviet physicist Georgy Flyorov, the founder of the Joint Institute for Nuclear Research in Dubna, Russia, where the element was discovered) is in the IUPAC name approval process.[1] Sony VAIO VGN-FW11S Battery
About 80 decays of atoms of ununquadium have been observed to date, 50 directly and 30 from the decay of the heavier elements ununhexium and ununoctium. All decays have been assigned to the five neighbouring isotopes with mass numbers 285–289. Sony VAIO VGN-FW139E/H Battery
The longest-lived isotope currently known is 289Uuq with a half-life of ~2.6 s, although there is evidence for anuclear isomer, 289bUuq, with a half-life of ~66 s, that would be one of the longest-lived nuclei in the superheavy element region. Sony VAIO VGN-FW140AE Battery
Chemical studies performed in 2007 strongly indicate that ununquadium possesses non-eka-lead properties and appears to behave as the first superheavy element that portrays noble-gas-like properties due to relativistic effects.[2] Sony VAIO VGN-FW140D Battery
Discovery
In December 1998, scientists at Dubna (Joint Institute for Nuclear Research) in Russia bombarded a 244Pu target with48Ca ions. A single atom of ununquadium, decaying by 9.67 MeV alpha-emission with a half-life of 30 s, was produced and assigned to 289Uuq.Sony VAIO VGN-FW140E Battery
Sony VAIO VGN-FW140E/H Battery
This observation was subsequently published in January 1999.[3] However, the decay chain observed has not been repeated and the exact identity of this activity is unknown, although it is possible that it is due to a meta-stable isomer, namely 289mUuq. Sony VAIO VGN-FW140E/W Battery
In March 1999, the same team replaced the 244Pu target with a 242Pu one in order to produce other isotopes. This time two atoms of ununquadium were produced, decaying by 10.29 MeV alpha-emission with a half-life of 5.5 s. They were assigned as 287Uuq.[4]Once again, this activity has not been seen again and it is unclear what nucleus was produced. Sony VAIO VGN-FW140N Battery
Sony VAIO VGN-FW140N/W Battery
It is possible that it was a meta-stable isomer, namely 287mUuq.
The now-confirmed discovery of ununquadium was made in June 1999 when the Dubna team repeated the 244Pu reaction. This time, two atoms of element 114 were produced decaying by emission of 9.82 MeV alpha particles with a half-life of 2.6 s.[5] Sony VAIO VGN-FW145E Battery,Sony VAIO VGN-FW145E/W Battery
This activity was initially assigned to 288Uuq in error, due to the confusion regarding the above observations. Further work in Dec 2002 has allowed a positive reassignment to 289Uuq.[6]
In May 2009, the Joint Working Party (JWP) of IUPAC published a report on the discovery of copernicium in which they acknowledged the discovery of the isotope283Cn.[7] Sony VAIO VGN-FW160AE Battery
This therefore implies the de facto discovery of ununquadium, from the acknowledgment of the data for the synthesis of 287Uuq and 291Uuh (see below), relating to 283Cn. In 2011, IUPAC evaluated the Dubna team experiments of 1999–2007. Whereas they found the early data inconclusive, the results of 2004–2007 were accepted as identification of element 114.[8] Sony VAIO VGN-FW160D Battery,Sony VAIO VGN-FW160E Battery
The discovery of ununquadium, as 287Uuq and 286Uuq, was confirmed in January 2009 at Berkeley. This was followed by confirmation of 288Uuq and 289Uuq in July 2009 at the GSI (see section 2.1.3).
Naming
Ununquadium (Uuq) is a temporary IUPAC systematic element name. The element is often referred to as element 114, for its atomic number. Sony VAIO VGN-FW160E/H Battery
Sony VAIO VGN-FW160F/E Battery
According to IUPAC recommendations, the discoverer(s) of a new element has the right to suggest a name.[9] The discovery of ununquadium was recognized by JWG of IUPAC on 1 June 2011, along with that of ununhexium.[8] According to the vice-director of JINR,[10] the Dubna team would like to name element 114 flerovium (symbolFl),[11][12] after Soviet physicist Georgy Flyorov (also spelled Flerov). Sony VAIO VGN-FW170J/H Battery,Sony VAIO VGN-FW180AE Battery
Future experiments
The team at RIKEN have indicated plans to study the cold fusion reaction:
The FLNR have future plans to study light isotopes of ununquadium, formed in the reaction between 239Pu and 48Ca. Sony VAIO VGN-FW180D Battery
Target-projectile combinations leading to Z=114 compound nuclei
The below table contains various combinations of targets and projectiles which could be used to form compound nuclei with an atomic number of 114.
Cold fusion
This section deals with the synthesis of nuclei of ununquadium by so-called “cold” fusion reactions. Sony VAIO VGN-FW180E/H Battery
These are processes which create compound nuclei at low excitation energy (~10–20 MeV, hence “cold”), leading to a higher probability of survival from fission. The excited nucleus then decays to the ground state via the emission of one or two neutrons only. Sony VAIO VGN-FW190EBH Battery
Sony VAIO VGN-FW190ECH Battery
208Pb(76Ge,xn)284?xUuq
The first attempt to synthesise ununquadium in cold fusion reactions was performed at Grand accélérateur national d’ions lourds(GANIL), France in 2003. No atoms were detected providing a yield limit of 1.2 pb. Sony VAIO VGN-FW190EDH Battery
Sony VAIO VGN-FW190NAH Battery
Hot fusion
This section deals with the synthesis of nuclei of ununquadium by so-called “hot” fusion reactions. These are processes which create compound nuclei at high excitation energy (~40–50 MeV, hence “hot”), leading to a reduced probability of survival from fission.Sony VAIO VGN-FW190NBH Battery
Sony VAIO VGN-FW190NCH Battery
The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing 48Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as “warm” fusion reactions. This leads, in part, to relatively high yields from these reactions. Sony VAIO VGN-FW190NDH Battery
Sony VAIO VGN-FW190NEH Battery
244Pu(48Ca,xn)292?xUuq (x=3,4,5)
The first experiments on the synthesis of ununquadium were performed by the team in Dubna in November 1998. They were able to detect a single, long decay chain, assigned to 289Uuq.[3] Sony VAIO VGN-FW198U/H Battery
Sony VAIO VGN-FW260J/B Battery
The reaction was repeated in 1999 and a further two atoms of ununquadium were detected. The products were assigned to 288Uuq.[5] The team further studied the reaction in 2002. During the measurement of the 3n, 4n, and 5n neutron evaporation excitation functions they were able to detect three atoms of289Uuq, Sony VAIO VGN-FW280J/H Battery,Sony VAIO VGN-FW290JRB Battery
twelve atoms of the new isotope 288Uuq, and one atom of the new isotope 287Uuq. Based on these results, the first atom to be detected was tentatively reassigned to 290Uuq or 289mUuq, whilst the two subsequent atoms were reassigned to 289Uuq and therefore belong to the unofficial discovery experiment.[6] Sony VAIO VGN-FW290JTB Battery,Sony VAIO VGN-FW290JTH Battery
In an attempt to study the chemistry of copernicium as the isotope 285Cn, this reaction was repeated in April 2007. Surprisingly, a PSI-FLNR directly detected two atoms of288Uuq forming the basis for the first chemical studies of ununquadium.
In June 2008, the experiment was repeated in order to further assess the chemistry of the element using the 289Uuq isotope. Sony VAIO VGN-FW290JTW Battery
Sony VAIO VGN-FW355J/H Battery
A single atom was detected seeming to confirm the noble-gas-like properties of the element.
During May–July 2009, the team at GSI studied this reaction for the first time, as a first step towards the synthesis of ununseptium. The team were able to confirm the synthesis and decay data for 288Uuq and 289Uuq, producing nine atoms of the former isotope and four atoms of the latter.[13] Sony VAIO VGN-FW373J/B Battery
242Pu(48Ca,xn)290?x114 (x=2,3,4,5)
The team at Dubna first studied this reaction in March–April 1999 and detected two atoms of ununquadium, assigned to 287Uuq.[4]The reaction was repeated in September 2003 in order to attempt to confirm the decay data for 287Uuq and 283Cn since conflicting data for 283Cn had been collected (see copernicium). Sony VAIO VGN-FW50B Battery,Sony VAIO VGN-FW51B/W Battery
The Russian scientists were able to measure decay data for 288Uuq, 287Uuq and the new isotope 286Uuq from the measurement of the 2n, 3n, and 4n excitation functions. [14][15]
In April 2006, a PSI-FLNR collaboration used the reaction to determine the first chemical properties of copernicium by producing 283Cn as an overshoot product. Sony VAIO VGN-FW51MF Battery,Sony VAIO VGN-FW51MF/H Battery
In a confirmatory experiment in April 2007, the team were able to detect 287Uuq directly and therefore measure some initial data on the atomic chemical properties of ununquadium.
The team at Berkeley, using the Berkeley gas-filled separator (BGS), continued their studies using newly acquired 242Pu targets by attempting the synthesis of ununquadium in January 2009 using the above reaction. Sony VAIO VGN-FW51ZF Battery
Sony VAIO VGN-FW51ZF/H Battery
In September 2009, they reported that they had succeeded in detecting two atoms of ununquadium, as 287Uuq and286Uuq, confirming the decay properties reported at the FLNR, although the measured cross sections were slightly lower; however the statistics were of lower quality.[16] Sony VAIO VGN-FW52JB Battery
In April 2009, the collaboration of Paul Scherrer Institute (PSI) and Flerov Laboratory of Nuclear Reactions (FLNR) of JINR carried out another study of the chemistry of ununquadium using this reaction. A single atom of 283Cn was detected. Sony VAIO VGN-FW70DB Battery
In December 2010, the team at the LBNL announced the synthesis of a single atom of the new isotope 285Uuq with the consequent observation of 5 new isotopes of daughter elements.
As a decay product
The isotopes of ununquadium have also been observed in the decay chains of ununhexium and ununoctium. Sony VAIO VGN-FW71DB/W Battery
285Uuq
In the claimed synthesis of 293Uuo in 1999, the isotope 285Uuq was identified as decaying by 11.35 MeV alpha emission with a half-life of 0.58 ms. The claim was retracted in 2001. This isotope was finally created in 2010 and its decay properties supported the fabrication of the previously published decay data. Sony VAIO VGN-FW73JGB Battery,Sony VAIO VGN-FW74FB Battery
Fission of compound nuclei with an atomic number of 114
Several experiments have been performed between 2000–2004 at the Flerov Laboratory of Nuclear Reactions in Dubna studying the fission characteristics of the compound nucleus 292Uuq. The nuclear reaction used is 244Pu+48Ca. Sony VAIO VGN-FW81HS Battery,Sony VAIO VGN-FW81NS Battery
The results have revealed how nuclei such as this fission predominantly by expelling closed shell nuclei such as 132Sn (Z=50, N=82). It was also found that the yield for the fusion-fission pathway was similar between 48Ca and 58Fe projectiles, indicating a possible future use of 58Fe projectiles in superheavy element formation.[19] Sony VAIO VGN-FW81S Battery,Sony VAIO VGN-FW82DS Battery
289Uuq
In the first claimed synthesis of ununquadium, an isotope assigned as 289Uuq decayed by emitting a 9.71 MeV alpha particle with a lifetime of 30 seconds. This activity was not observed in repetitions of the direct synthesis of this isotope. Sony VAIO VGN-FW82JS Battery,Sony VAIO VGN-FW82XS Battery
However, in a single case from the synthesis of 293Uuh, a decay chain was measured starting with the emission of a 9.63 MeV alpha particle with a lifetime of 2.7 minutes. All subsequent decays were very similar to that observed from 289Uuq, presuming that the parent decay was missed. Sony VAIO VGN-FW83DS Battery
This strongly suggests that the activity should be assigned to an isomeric level. The absence of the activity in recent experiments indicates that the yield of the isomer is ~20% compared to the supposed ground state and that the observation in the first experiment was a fortunate (or not as the case history indicates). Further research is required to resolve these issues. Sony VAIO VGN-FW83XS Battery
287Uuq
In a manner similar to those for 289Uuq, first experiments with a 242Pu target identified an isotope 287Uuq decaying by emission of a 10.29 MeV alpha particle with a lifetime of 5.5 seconds. Sony VAIO VGN-FW90NS Battery
The daughter spontaneously fissioned with a lifetime in accord with the previous synthesis of 283Cn. Both these activities have not been observed since (see copernicium). However, the correlation suggests that the results are not random and are possible due to the formation of isomers whose yield is obviously dependent on production methods. Sony VAIO VGN-FW91NS Battery
Further research is required to unravel these discrepancies.
Yields of isotopes
The tables below provide cross-sections and excitation energies for fusion reactions producing ununquadium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel. Sony VAIO VGN-FW92DS Battery
Evaporation residue cross sections
The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given.
MD = multi-dimensional; DNS = Dinuclear system; ? = cross section Sony VAIO VGN-FW93DS Battery
Decay characteristics
Theoretical estimation of the alpha decay half-lives of the isotopes of the ununquadium supports the experimental data.[23][24] The fission-survived isotope 298Uuq is predicted to have alpha decay half-life around 17 days.[25][26] Sony VAIO VGN-FW93XS Battery,Sony VAIO VGN-FW94FS Battery
In search for the island of stability: 298Uuq
According to macroscopic-microscopic (MM) theory[citation needed], Z=114 is the next spherical magic number. This means that such nuclei are spherical in their ground state and should have high, wide fission barriers to deformation and hence long SF partial half-lives. Sony VAIO VGN-FW94GS Battery
In the region of Z=114, MM theory indicates that N=184 is the next spherical neutron magic number and puts forward the nucleus 298Uuq as a strong candidate for the next spherical doubly magic nucleus, after 208Pb (Z=82, N=126). 298Uuq is taken to be at the centre of a hypothetical “island of stability”. Sony VAIO VGN-G118CN Battery
Sony VAIO VGN-G118GN/B Battery
However, other calculations using relativistic mean field (RMF) theory propose Z=120, 122, and 126 as alternative proton magic numbers depending upon the chosen set of parameters. It is possible that rather than a peak at a specific proton shell, there exists a plateau of proton shell effects from Z=114–126. Sony VAIO VGN-G118GN/T Battery
Sony VAIO VGN-G118TN/B Battery
It should be noted that calculations suggest that the minimum of the shell-correction energy and hence the highest fission barrier exists for 297Uup, caused by pairing effects. Due to the expected high fission barriers, any nucleus within this island of stability will exclusively decay by alpha-particle emission and as such the nucleus with the longest half-life is predicted to be 298Uuq. Sony VAIO VGN-G118TN/S Battery
The expected half-life is unlikely to reach values higher than about 10 minutes, unless the N=184 neutron shell proves to be more stabilising than predicted, for which there exists some evidence.[citation needed] In addition, 297Uuq may have an even-longer half-lifedue to the effect of the odd neutron, creating transitions between similar Nilsson levels with lower Qalpha values. Sony VAIO VGN-G11VN/TC Battery
In either case, an island of stability does not represent nuclei with the longest half-lives but those which are significantly stabilized against fission by closed-shell effects. Sony VAIO VGN-G1AAPS Battery
Evidence for Z=114 closed proton shell
While evidence for closed neutron shells can be deemed directly from the systematic variation of Qalpha values for ground-state to ground-state transitions, evidence for closed proton shells comes from (partial) spontaneous fission half-lives. Sony VAIO VGN-G1AAPSA Battery
Such data can sometimes be difficult to extract due to low production rates and weak SF branching. In the case of Z=114, evidence for the effect of this proposed closed shell comes from the comparison between the nuclei pairings 282Cn (TSF1/2 = 0.8 ms) and 286Uuq (TSF1/2 = 130 ms), and 284Cn (TSF = 97 ms) and 288Uuq (TSF >800 ms). Sony VAIO VGN-G1AAPSC Battery
Further evidence would come from the measurement of partial SF half-lives of nuclei with Z>114, such as 290Uuh and 292Uuo (both N=174 isotones). The extraction of Z=114 effects is complicated by the presence of a dominating N=184 effect in this region. Sony VAIO VGN-G1KAP Battery
Difficulty of synthesis of 298Uuq
The direct synthesis of the nucleus 298Uuq by a fusion-evaporation pathway is impossible since no known combination of target and projectile can provide 184 neutrons in the compound nucleus. Sony VAIO VGN-G1KBNA Battery
It has been suggested that such a neutron-rich isotope can be formed by the quasifission (partial fusion followed by fission) of a massive nucleus. Such nuclei tend to fission with the formation of isotopes close to the closed shells Z=20/N=20 (40Ca), Z=50/N=82 (132Sn) or Z=82/N=126 (208Pb/209Bi). Sony VAIO VGN-G1LBN Battery
Sony VAIO VGN-G218LN/T Battery
If Z=114 does represent a closed shell, then the hypothetical reaction below may represent a method of synthesis:
Recently it has been shown that the multi-nucleon transfer reactions in collisions of actinide nuclei (such as uranium and curium) might be used to synthesize the neutron rich superheavy nuclei located at the island of stability.[27] Sony VAIO VGN-G218N/B Battery,Sony VAIO VGN-G21XP/B Battery
It is also possible that 298Uuq can be synthesized by the alpha decay of a massive nucleus. Such a method would depend highly on the SF stability of such nuclei, since the alpha half-lives are expected to be very short. The yields for such reactions will also most likely be extremely small. One such reaction is: Sony VAIO VGN-G2AANS Battery
Oxidation states
Ununquadium is projected to be the second member of the 7p series of chemical elements and the heaviest member of group 14 (IVA) in the Periodic Table, below lead. Each of the members of this group show the group oxidation state of +IV and the latter members have an increasing +II chemistry due to the onset of the inert pair effect. Sony VAIO VGN-G2AAPSA Battery,Sony VAIO VGN-G2AAPSB Battery
Tin represents the point at which the stability of the +II and +IV states are similar. Lead, the heaviest member, portrays a switch from the +IV state to the +II state. Ununquadium should therefore follow this trend and a possess an oxidising +IV state and a stable +II state. Sony VAIO VGN-G2AAPSC Battery
Chemistry
Ununquadium should portray eka-lead chemical properties and should therefore form a monoxide, UuqO, and dihalides, UuqF2, UuqCl2, UuqBr2, and UuqI2. If the +IV state is accessible, it is likely that it is only possible in the oxide, UuqO2, and fluoride, UuqF4. It may also show a mixed oxide, Uuq3O4, analogous to Pb3O4. Sony VAIO VGN-G2KANA Battery
Some studies also suggest that the chemical behaviour of ununquadium might in fact be closer to that of the noble gas radon, than to that of lead.[2]
Calculations suggest that ununquadium will not form a tetrafluoride, UuqF4, but will form a difluoride (UuqF2) that is soluble in water.[28] Sony VAIO VGN-NR160E/S Battery
Sony VAIO VGN-NR160E/T Battery
Atomic gas phase
Two experiments were performed in April–May 2007 in a joint FLNR-PSI collaboration aiming to study the chemistry of copernicium. The first experiment involved the reaction 242Pu(48Ca,3n)287Uuq and the second the reaction 244Pu(48Ca,4n)288Uuq. Sony VAIO VGN-NR160E/W Battery
Sony VAIO VGN-NR180E/S Battery
The adsorption properties of the resultant atoms on a gold surface were compared with those of radon. The first experiment allowed detection of 3 atoms of 283Cn but also seemingly detected 1 atom of 287Uuq. This result was a surprise given the transport time of the product atoms is ~2 s, so ununquadium atoms should decay before adsorption. Sony VAIO VGN-NR180E/T Battery
Sony VAIO VGN-NR290E/S Battery
In the second reaction, 2 atoms of 288Uuq and possibly 1 atom of289Uuq were detected. Two of the three atoms portrayed adsorption characteristics associated with a volatile, noble-gas-like element, which has been suggested but is not predicted by more recent calculations. Sony VAIO VGN-NR290E/T Battery
Sony VAIO VGN-NR298E/S Battery
These experiments did however provide independent confirmation for the discovery of copernicium, ununquadium, andununhexium via comparison with published decay data. Further experiments were performed in 2008 to confirm this important result and a single atom of 289Uuq was detected which gave data in agreement with previous data in support of ununquadium having a noble-gas-like interaction with gold.[29] Sony VAIO VGN-NR460E/L Battery,Sony VAIO VGN-NR460E/P Battery
In April 2009, the FLNR-PSI collaboration synthesized a further atom of element 114.
Ununpentium is the temporary name of a synthetic superheavy element in the periodic table that has the temporary symbol Uupand has the atomic number 115. Sony VAIO VGN-NR498E/L Battery
It is placed as the heaviest member of group 15 (VA) although a sufficiently stable isotope is not known at this time that would allow chemical experiments to confirm its position. It was first observed in 2003 and about 50 atoms of ununpentium have been synthesized to date, with about 25 direct decays of the parent element having been detected. Sony VAIO VGN-NR498E/S Battery
Sony VAIO VGN-NR498E/T Battery
Four consecutive isotopes are currently known, 287–290Uup, with 289Uup having the longest measured half-life of ~200 ms.[1]
Discovery profile
Simulation of an accelerated calcium-48 ion about to collide with an americium-243 target atom. Sony VAIO VGN-NR498E/W Battery
On February 2, 2004, synthesis of ununpentium was reported in Physical Review C by a team composed of Russian scientists at the Joint Institute for Nuclear Research in Dubna, and American scientists at the Lawrence Livermore National Laboratory.[2][3]Sony VAIO VGN-NR50B Battery
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 ununtrium in approximately 100 milliseconds. Sony VAIO VGN-NR51 Battery
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.[4][5] Sony VAIO VGN-NR51B Battery
Both the half-life and decay mode were confirmed for the proposed 268Db which lends support to the assignment of Z=115 to the parent nuclei.
Sergei Dmitriev from the Flerov Laboratory of Nuclear Reactions (FLNR) in Dubna, Russia, has formally put forward their claim of discovery of ununpentium to the Joint Working Party (JWP) from IUPAC and IUPAP.[6] Sony VAIO VGN-NR52B Battery
In 2011, the IUPAC evaluated the Dubna-Livermore results and concluded that they did not meet the criteria for discovery.[7]
Recent experiments at Dubna have fully confirmed the data for ununpentium and ununtrium but have yet to be fully published and reviewed by the JWP. This process is likely not to occur for some time. Sony VAIO VGN-NR71B2 Battery
Naming
Ununpentium is historically known as eka-bismuth. Ununpentium is a temporary IUPAC systematic element name derived from the digits 115, where “un-” represents Latin unum. Sony VAIO VGN-NS10E/S Battery
“Pent-” represents the Greek word for 5, and it was chosen because the Latin word for 5 starts with ‘q’, which would have caused confusion with ununquadium, element 114. Research scientists usually refer to the element simply as element 115. Sony VAIO VGN-NS10L/S Battery,Sony VAIO VGN-NS110E/L Battery
Current and future experiments
The team at Dubna are currently running another series of experiments on the 243Am(48Ca,xn) reaction. They are attempting to complete the 4n excitation function and confirm the data for 287115. They are also hoping to identify some decays from the 2n and 5n exit channels. This reaction will run until the Christmas shutdown. Sony VAIO VGN-NS110E/S Battery,Sony VAIO VGN-NS110E/W Battery
The FLNR also have future plans to study light isotopes of element 115 using the reaction 241Am + 48Ca.[8]
Target-projectile combinations leading to Z=115 compound nuclei
The table below contains various combinations of targets and projectiles which could be used to form compound nuclei with Z=115.Sony VAIO VGN-NS115N/S Battery
Sony VAIO VGN-NS11ER/S Battery
Hot fusion
This section deals with the synthesis of nuclei of ununpentium by so-called “hot” fusion reactions. These are processes which create compound nuclei at high excitation energy (~40–50 MeV, hence “hot”), leading to a reduced probability of survival from fission.Sony VAIO VGN-NS11E/S Battery
The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing 48Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as “warm” fusion reactions. This leads, in part, to relatively high yields from these reactions. Sony VAIO VGN-NS11L/S Battery
Sony VAIO VGN-NS11MR/S Battery
238U(51V,xn)289?xUup
There are strong indications that this reaction was performed in late 2004 as part of a uranium(IV) fluoride target test at the GSI. No reports have been published suggesting that no products atoms were detected, as anticipated by the team.[9] Sony VAIO VGN-NS11M/S Battery,Sony VAIO VGN-NS11SR/S Battery
243Am(48Ca,xn)291?xUup (x=2,3,4)
This reaction was first performed by the team in Dubna in July–August 2003. In two separate runs they were able to detect 3 atoms of 288Uup and a single atom of287Uup. The reaction was studied further in June 2004 in an attempt to isolate the descendant 268Db from the 288Uup decay chain. Sony VAIO VGN-NS11S/S Battery
Sony VAIO VGN-NS11ZR/S Battery
After chemical separation of a +4/+5 fraction, 15 SF decays were measured with a lifetime consistent with 268Db. In order to prove that the decays were from dubnium-268, the team repeated the reaction in August 2005 and separated the +4 and +5 fractions and further separated the +5 fractions into tantalum-like and niobium-like ones. Sony VAIO VGN-NS11Z/S Battery
Five SF activities were observed, all occurring in the +5 fractions and none in the tantalum-like fractions, proving that the product was indeed isotopes of dubnium.
In a series of experiments between October 2010 – February 2011, scientists at the FLNR studied this reaction at a range of excitation energies. Sony VAIO VGN-NS12S/S Battery,Sony VAIO VGN-NS21M/P Battery
They were able to detect 21 atoms of 288115 and one atom of 289115, from the 2n exit channel. This latter result was used to support the synthesis of ununseptium. The 3n excitation function was completed with a maximum at ~8 pb. The data was consistent with that found in the first experiments in 2003. Sony VAIO VGN-NS21M/W Battery
Hot fusion
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. Sony VAIO VGN-NS21S/W Battery
Theoretical calculations
Theoretical calculations using a quantum-tunneling model support the experimental alpha-decay half-lives.[10] Sony VAIO VGN-NS31M/P Battery
Evaporation residue cross sections
The table below contains various target-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given. Sony VAIO VGN-NS31M/W Battery,Sony VAIO VGN-NS31S/S Battery
MD = multi-dimensional; DNS = Di-nuclear system; ? = cross section
Oxidation states
Ununpentium is projected to be the third member of the 7p series of chemical elements and the heaviest member of group 15 (VA) in the Periodic Table, below bismuth. Sony VAIO VGN-NS31Z/P Battery
In this group, each member is known to portray the group oxidation state of +V but with differing stability. For nitrogen, the +V state is very difficult to achieve due to the lack of low-lying d-orbitals and the inability of the small nitrogen atom to accommodate five ligands. The +V state is well represented for phosphorus,arsenic, and antimony. Sony VAIO VGN-NS31Z/W Battery
However, for bismuth it is rare due to the reluctance of the 6s2 electron to participate in bonding. This effect is known as the “inert pair effect” and is commonly linked to relativistic stabilisation of the 6s-orbitals. It is expected that ununpentium will continue this trend and portray only +III and +I oxidation states. Sony VAIO VGN-NS38M/W Battery,Sony VAIO VGN-NS130E/L Battery,Sony VAIO VGN-NS130E/S Battery
Nitrogen(I) and bismuth(I) are known but rare and Uup(I) is likely to show some unique properties.[13] Because of spin-orbit coupling,ununquadium may display closed-shell or noble gas-like properties; if this is the case, Uup will likely be monovalent as a result, since the cation Uup+ will have the same electron configuration as Uuq. Sony VAIO VGN-NS130E/W Battery
Sony VAIO VGN-NS140E/L Battery
Chemistry
Ununpentium should display eka-bismuth chemical properties and should therefore form a sesquioxide, Uup2O3, and anologous chalcogenides, Uup2S3, Uup2Se3 and Uup2Te3. It should also form trihydrides and trihalides, i.e. UupH3, UupF3, UupCl3, UupBr3 and UupI3. If the +V state is accessible, it is likely that it is only possible in the fluoride, UupF5.[14] Sony VAIO VGN-NS140E/S Battery
Sony VAIO VGN-NS140E/W Battery
Stability
All the reported above isotopes of element 115, obtained by nuclear collisions of lighter nuclei, are severely neutron-deficient, because the proportion of neutrons to protons needed for maximum stability increases with atomic number. Sony VAIO VGN-NS190J/L Battery,Sony VAIO VGN-NS190J/S Battery
The most stable isotope will probably be 299Uup, with 184 neutrons, a known “magic” closed-shell number conferring exceptional stability, making it (with one further proton outside the “magic number” of 114 protons) both the chemical and the nuclear homolog of 209Bi; but the technology required to add the required neutrons presently does not exist. Sony VAIO VGN-NS190J/W Battery
Sony VAIO VGN-NS235J/L Battery
This is because no known combination of target and projectile can result in the required neutrons. It has been suggested that such a neutron-rich isotope could be formed by quasifission (fusion followed by fission) of a massive nucleus, multi-nucleon transfer reactions in collisions of actinide nuclei, or by the alpha decay of a massive nucleus (although this would depend on the stability of the parent nuclei towards spontaneous fission). Sony VAIO VGN-NS235J/P Battery
Sony VAIO VGN-NS235J/S Battery
Ununhexium is the temporary name of a synthetic superheavy element with the temporary symbol Uuh and atomic number 116. As of December 1, 2011, the name livermorium is in the IUPAC name approval process.[1] Sony VAIO VGN-NS235J/W Battery
It is placed as the heaviest member of group 16 (VIA) although a sufficiently stable isotope is not known at this time to allow chemical experiments to confirm its position as the heavier homologue to polonium. Sony VAIO VGN-NS240E/L Battery
It was first detected in 2000 and since the discovery about 35 atoms of ununhexium have been produced, either directly or as a decay product of ununoctium, and are associated with decays from the four neighbouring isotopes with masses 290–293. The most stable isotope to date is ununhexium-293 with a half-life of ~60 ms. Sony VAIO VGN-NS290J/L Battery,Sony VAIO VGN-NS290J/S Battery
Discovery
On July 19, 2000, scientists at Dubna (JINR) detected a single decay from an atom of ununhexium following the irradiation of a Cm-248 target with Ca-48 ions. The results were published in December, 2000.[2] Sony VAIO VGN-NS50B/L Battery
This 10.54 MeV alpha-emitting activity was originally assigned to 292Uuh due to the correlation of the daughter to previously assigned 288Uuq. However, that assignment was later altered to 289Uuq, and hence this activity was correspondingly changed to 293Uuh. Sony VAIO VGN-NS51B/L Battery
Two further atoms were reported by the institute during their second experiment between April–May 2001.[3]
In the same experiment they also detected a decay chain which corresponded to the first observed decay of ununquadium and assigned to 289Uuq.[3] Sony VAIO VGN-NS51B/W Battery,Sony VAIO VGN-NS52JB/L Battery
This activity has not been observed again in a repeat of the same reaction. However, its detection in this series of experiments indicates the possibility of the decay of an isomer of ununhexium, namely 293bUuh, or a rare decay branch of the already discovered isomer,293aUuh, in which the first alpha particle was missed. Further research is required to positively assign this activity. Sony VAIO VGN-NS52JB/P Battery
Sony VAIO VGN-NS52JB/W Battery
The team repeated the experiment in April–May 2005 and detected 8 atoms of ununhexium. The measured decay data confirmed the assignment of the discovery isotope as293Uuh. In this run, the team also observed 292Uuh in the 4n channel for the first time.[4]Sony VAIO VGN-NS70B/W Battery
In May 2009, the Joint Working Party reported on the discovery of copernicium and acknowledged the discovery of the isotope 283Cn.[5] This implied the de factodiscovery of ununhexium, as 291Uuh (see below), from the acknowledgment of the data relating to the granddaughter 283Cn, although the actual discovery experiment may be determined as that above. Sony VAIO VGN-NS72JB/W Battery
In 2011, the IUPAC evaluated the Dubna team results and accepted them as a reliable identification of element 116.[6]
Naming
Ununhexium is historically known as eka-polonium.[7] Ununhexium (Uuh) is a temporary IUPAC systematic element name. Sony VAIO VGN-NS92JS Battery
Scientists usually refer to the element simply aselement 116 (or E116). According to IUPAC recommendations, the discoverer(s) of a new element has the right to suggest a name.[8]
The discovery of ununhexium was recognized by JWG of IUPAC on 1 June 2011, along with that of ununquadium.[6] Sony VAIO VGN-NW11S/S Battery
According to the vice-director of JINR, the Dubna team would like to name element 116 moscovium, after the Moscow Oblast in which Dubna is located.[9]
As of December 1, 2011, the name livermorium and the symbol Lv are in the IUPAC name approval process.[1] Sony VAIO VGN-NW11Z/S Battery
The name recognises the Lawrence Livermore National Laboratory, in Livermore, California, USA, which collaborated with JINR on the discovery.
Current and future experiments
The team at Dubna have indicated plans to synthesize ununhexium using the reaction between plutonium-244 and titanium-50. Sony VAIO VGN-NW21EF/S Battery
This experiment will allow them to assess the feasibility of using projectiles with Z > 20 required in the synthesis of superheavy elements with Z>118. Although initially scheduled for 2008, the reaction looking at the synthesis of evaporation residues has not been conducted to date.[10] Sony VAIO VGN-NW21MF Battery
Sony VAIO VGN-NW21MF/W Battery
There are also plans to repeat the Cm-248 reaction at different projectile energies in order to probe the 2n channel, leading to the new isotope 294Uuh. In addition, they have future plans to complete the excitation function of the 4n channel product, 292Uuh, which will allow them to assess the stabilizing effect of the N=184 shell on the yield of evaporation residues. Sony VAIO VGN-NW21ZF Battery
Sony VAIO VGN-NW31EF/W Battery
Target-projectile combinations leading to Z=116 compound nuclei
The below table contains various combinations of targets and projectiles which could be used to form compound nuclei with atomic number 116. Sony VAIO VGN-NW31JF Battery
208Pb(82Se,xn)290?xUuh
In 1998, the team at GSI attempted the synthesis of 290Uuh as a radiative capture (x=0) product. No atoms were detected providing a cross section limit of 4.8 pb.
Hot fusion
This section deals with the synthesis of nuclei of ununhexium by so-called “hot” fusion reactions. Sony VAIO VGN-NW320F/B Battery
Sony VAIO VGN-NW320F/TC Battery
These are processes which create compound nuclei at high excitation energy (~40–50 MeV, hence “hot”), leading to a reduced probability of survival from fission. The excited nucleus then decays to the ground state via the emission of 3–5 neutrons. Fusion reactions utilizing 48Ca nuclei usually produce compound nuclei with intermediate excitation energies (~30–35 MeV) and are sometimes referred to as “warm” fusion reactions. Sony VAIO VGN-NW35E Battery
Sony VAIO VGN-NW380F/S Battery
This leads, in part, to relatively high yields from these reactions.
238U(54Cr,xn)292?xUuh
There are sketchy indications that this reaction was attempted by the team at GSI in 2006. There are no published results on the outcome, presumably indicating that no atoms were detected. This is expected from a study of the systematics of cross sections for 238U targets.[11] Sony VAIO VGN-NW380F/T Battery
248Cm(48Ca,xn)296?xUuh (x=3,4)
The first attempt to synthesise ununhexium was performed in 1977 by Ken Hulet and his team at the Lawrence Livermore National Laboratory (LLNL). They were unable to detect any atoms of ununhexium.[12] Sony VAIO VGN-NW51FB/N Battery
Sony VAIO VGN-NW51FB/W Battery
Yuri Oganessian and his team at the Flerov Laboratory of Nuclear Reactions (FLNR) subsequently attempted the reaction in 1978 and were met by failure. In 1985, a joint experiment between Berkeley and Peter Armbruster’s team at GSI, the result was again negative with a calculated cross-section limit of 10–100 pb.[13] Sony VAIO VGN-NW70JB Battery
Sony VAIO VGN-NW71FB/N Battery
In 2000, Russian scientists at Dubna finally succeeded in detecting a single atom of ununhexium, assigned to the isotope 292Uuh.[2]In 2001, they repeated the reaction and formed a further 2 atoms in a confirmation of their discovery experiment. A third atom was tentatively assigned to 293Uuh on the basis of a missed parental alpha decay.[3] Sony VAIO VGN-NW71FB/W Battery
In April 2004, the team ran the experiment again at higher energy and were able to detect a new decay chain, assigned to 292Uuh. On this basis, the original data were reassigned to 293Uuh. The tentative chain is therefore possibly associated with a rare decay branch of this isotope. In this reaction, 2 further atoms of 293Uuh were detected.[4] Sony VAIO VGN-NW91GS Battery,Sony VAIO VGN-NW91VS Battery
In an experiment run at the GSI between June-July 2010, scientists detected six atoms of unuhexium; two atoms of 293116 and four atoms of 292116. They were able to confirm both the decay data and cross sections for the fusion reaction. Sony VAIO VGN-SR11M Battery
245Cm(48Ca,xn)293?x116 (x=2,3)
In order to assist in the assignment of isotope mass numbers for ununhexium, in March–May 2003 the Dubna team bombarded a 245Cm target with 48Ca ions. They were able to observe two new isotopes, assigned to 291Uuh and 290Uuh.[14] Sony VAIO VGN-SR11MR Battery,Sony VAIO VGN-SR140D Battery
This experiment was successfully repeated in Feb–March 2005 where 10 atoms were created with identical decay data to those reported in the 2003 experiment.[15]
As a decay product
Ununhexium has also been observed in the decay of ununoctium. Sony VAIO VGN-SR140D/B Battery,Sony VAIO VGN-SR140D/P Battery
In October 2006 it was announced that 3 atoms of ununoctium had been detected by the bombardment ofcalifornium-249 with calcium-48 ions, which then rapidly decayed into ununhexium.[15]
The observation of 290Uuh allowed the assignment of the product to 294Uuo and proved the synthesis of ununoctium. Sony VAIO VGN-SR140D/S Battery
Fission of compound nuclei with Z=116
Several experiments have been performed between 2000–2006 at the Flerov laboratory of Nuclear Reactions in Dubna studying the fission characteristics of the compound nuclei 296,294,290Uuh. Four nuclear reactions have been used, namely 248Cm+48Ca, 246Ca+48Ca, 244Pu+50Ti and 232Th+58Fe. Sony VAIO VGN-SR140E/B Battery,Sony VAIO VGN-SR140E/P Battery
The results have revealed how nuclei such as this fission predominantly by expelling closed shell nuclei such as 132Sn (Z=50, N=82). It was also found that the yield for the fusion-fission pathway was similar between 48Ca and 58Fe projectiles, indicating a possible future use of 58Fe projectiles in superheavy element formation. Sony VAIO VGN-SR140E/S Battery,Sony VAIO VGN-SR140N/S Battery
In addition, in comparative experiments synthesizing 294Uuh using 48Ca and 50Ti projectiles, the yield from fusion-fission was ~3x less for 50Ti, also suggesting a future use in SHE production[16]
289Uuh
In 1999, researchers at Lawrence Berkeley National Laboratory announced the synthesis of 293Uuo (see ununoctium), in a paper published in Physical Review Letters.[17] Sony VAIO VGN-SR165E/B Battery
Sony VAIO VGN-SR165E/P Battery
The claimed isotope 289Uuh decayed by 11.63 MeV alpha emission with a half-life of 0.64 ms. The following year, they published a retraction after other researchers were unable to duplicate the results.[18] 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. Sony VAIO VGN-SR165E/S Battery
Sony VAIO VGN-SR190EBJ Battery
As such, this isotope of ununhexium is currently unknown.
Hot fusion
The table below provides cross-sections and excitation energies for hot fusion reactions producing ununhexium isotopes directly. Data in bold represent maxima derived from excitation function measurements. + represents an observed exit channel. Sony VAIO VGN-SR190EBQ Battery
Sony VAIO VGN-SR190EEJ/C Battery
Decay characteristics
Theoretical calculation in a quantum tunneling model supports the experimental data relating to the synthesis of 293,292Uuh.[20][21]
Evaporation residue cross sections
The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. Sony VAIO VGN-SR190NAB Battery
Sony VAIO VGN-SR190NBB Battery
The channel with the highest expected yield is given.
DNS = Di-nuclear system; ? = cross section
Oxidation states
Ununhexium is projected to be the fourth member of the 7p series of non-metals and the heaviest member of group 16 (VIA) in the Periodic Table, below polonium. Sony VAIO VGN-SR190NDB Battery,Sony VAIO VGN-SR190NEB Battery
The group oxidation state of +VI is known for all the members apart from oxygen which lacks available d-orbitals for expansion and is limited to a maximum +II state, exhibited in the fluoride OF2. The +IV is known for sulfur, selenium, tellurium, and polonium, undergoing a shift in stability from reducing for S(IV) and Se(IV) to oxidizing in Po(IV). Sony VAIO VGN-SR190NGB Battery
Sony VAIO VGN-SR190PAB Battery
Tellurium(IV) is the most stable for this element. This suggests a decreasing stability for the higher oxidation states as the group is descended and ununhexium should portray an oxidizing +IV state and a more stable +II state. The lighter members are also known to form a ?II state as oxide,sulfide, selenide, telluride, and polonide. Sony VAIO VGN-SR190PCB Battery,Sony VAIO VGN-SR190PFB Battery
Chemistry
The possible chemistry of ununhexium can be extrapolated from that of polonium. It should therefore undergo oxidation to a dioxide, UuhO2, although a trioxide, UuhO3is plausible, but unlikely. Sony VAIO VGN-SR19VN Battery
The stability of a +II state should manifest itself in the formation of a simple monoxide, UuhO. Fluorination will likely result in a tetrafluoride, UuhF4 and/or a difluoride, UuhF2. Chlorination and bromination may well stop at the corresponding dihalides, UuhCl2 and UuhBr2. Sony VAIO VGN-SR19VRN Battery
Oxidation by iodineshould certainly stop at UuhI2 and may even be inert to this element. Sony VAIO VGN-SR19XN Battery, Sony VAIO VGN-SR210J/S Battery,Sony VAIO VGN-SR21M/S Battery,Sony VAIO VGN-SR21RM/H Battery,Sony VAIO VGN-SR21RM/S Battery
