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6 février 2012 1 06 /02 /février /2012 03:54

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

Sony VAIO VGN-FW30B 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

Sony VAIO VGN-FW54FB 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

Sony VAIO VGN-FW72JGB 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

Sony VAIO VGN-FW83JS 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

Sony VAIO VGN-FW90HS 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

Sony VAIO VGN-FW90S 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

Sony VAIO VGN-FW91S 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

Sony VAIO VGN-FW92JS 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

Sony VAIO VGN-FW93JS 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

Sony VAIO VGN-FW94HS 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

Sony VAIO VGN-G11VN/T 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

Sony VAIO VGN-G11XN/B 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

Sony VAIO VGN-G1AAPSB 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

Sony VAIO VGN-G1ABNS 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

Sony VAIO VGN-G1KBN 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

Sony VAIO VGN-G1LAP 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

Sony VAIO VGN-G2AAPS 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

Sony VAIO VGN-G2KAN 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

Sony VAIO VGN-G2KBNA 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

Sony VAIO VGN-NR50 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

Sony VAIO VGN-NR52 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

Sony VAIO VGN-NR71B 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

Sony VAIO VGN-NR72B 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

Sony VAIO VGN-NS10J/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

Sony VAIO VGN-NS11J/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

Sony VAIO VGN-NS12M/S Battery

Sony VAIO VGN-NS12M/W 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

Sony VAIO VGN-NS21S/S 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

Sony VAIO VGN-NS21Z/S 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

Sony VAIO VGN-NS31Z/S 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

Sony VAIO VGN-NS38M/P 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

Sony VAIO VGN-NS50B/W 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

Sony VAIO VGN-NS51B/P 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

Sony VAIO VGN-NS71B/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

Sony VAIO VGN-NS90HS 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

Sony VAIO VGN-NS92XS 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

Sony VAIO VGN-NW11S/T 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

Sony VAIO VGN-NW11Z/T 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

Sony VAIO VGN-NW21JF 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. ptopbattery-pack.co.uk/original-sony-vaio-vgn-nw320f-b-battery-27386.htm" title="Sony VAIO VGN-NW320F/B laptop battery">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

Sony VAIO VGN-NW50JB 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

Sony VAIO VGN-NW91FS 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

Sony VAIO VGN-SR140E 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

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

Sony VAIO VGN-SR19XN Battery

Oxidation by iodineshould certainly stop at UuhI2 and may even be inert to this element. Sony VAIO VGN-SR19XN BatterySony VAIO VGN-SR210J/S Battery,Sony VAIO VGN-SR21M/S Battery,Sony VAIO VGN-SR21RM/H Battery,Sony VAIO VGN-SR21RM/S Battery

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