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6 février 2012 1 06 /02 /février /2012 03:52

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

Sony VAIO VGN-AW90NS 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

Sony VAIO VGN-AW90US 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

Sony VAIO VGN-AW92JS 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

Sony VAIO VGN-AW93ZGS 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

Sony VAIO VGN-CR13G/R 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

Sony VAIO VGN-CR33 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

Sony VAIO VGN-CR50B/W 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

Sony VAIO VGN-CR60B/L 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

Sony VAIO VGN-CR61B/P 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

Sony VAIO VGN-CR62B/L 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

Sony VAIO VGN-CR62B/P 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

Sony VAIO VGN-CR70B/W 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

Sony VAIO VGN-CR72B/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

Sony VAIO VGN-CR90NS 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

Sony VAIO VGN-CR92HS 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

Sony VAIO VGN-CR92S 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

Sony VAIO VGN-CS11S/P 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

Sony VAIO VGN-CS11S/W 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: 

e="Sony VAIO VGN-CS190NCB laptop battery">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

Sony VAIO VGN-CS60B/Q 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

Sony VAIO VGN-CS61B/P 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

Sony VAIO VGN-CS61B/R 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

Sony VAIO VGN-CS90HS 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

Sony VAIO VGN-CS90S 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

Sony VAIO VGN-CS92XS 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

Sony VAIO VGN-FW11M 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

Sony VAIO VGN-FW11ZU 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

Sony VAIO VGN-FW140FE 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

Sony VAIO VGN-FW180E 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

Sony VAIO VGN-FW180FU 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

 

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