Tennessine: Difference between revisions

Tennessine, ₁₁₇Ts
Tennessine
Pronunciation	/ˈtɛnəsiːn/ (TEN-ə-seen)
Appearance	semimetallic (predicted)
Mass number	[294]
Tennessine in the periodic table
	livermorium ← tennessine → oganesson
Atomic number (Z)	117
Group	group 17 (halogens)
Period	period 7
Block	p-block
Electron configuration	[Rn] 5f14 6d10 7s2 7p5 (predicted)
Electrons per shell	2, 8, 18, 32, 32, 18, 7 (predicted)
Physical properties
Phase at STP	solid (predicted)
Melting point	623–823 K (350–550 °C, 662–1022 °F) (predicted)
Boiling point	883 K (610 °C, 1130 °F) (predicted)
Density (near r.t.)	7.1–7.3 g/cm3 (extrapolated)
Atomic properties
Oxidation states	(−1), (+1), (+3), (+5) (predicted)
Ionization energies	1st: 742.9 kJ/mol (predicted); 2nd: 1435.4 kJ/mol (predicted); 3rd: 2161.9 kJ/mol (predicted); (more) ;
Atomic radius	empirical: 138 pm (predicted)
Covalent radius	156–157 pm (extrapolated)
Other properties
Natural occurrence	synthetic
CAS Number	54101-14-3
History
Naming	after Tennessee region
Discovery	Joint Institute for Nuclear Research, Lawrence Livermore National Laboratory, Vanderbilt University and Oak Ridge National Laboratory (2010)
Isotopes of tennessine v; e;
	Category: Tennessine; view; talk; edit; \| references

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Ununseptium is the temporary name of a superheavy artificial chemical element with temporary symbol Uus and atomic number 117. The element, also known as eka-astatine or simply element 117, is the second-heaviest element of all created. Its discovery was first announced in 2010, when the element was claimed to have been created in Dubna by a joint Russian–American collaboration.^[9] Another experiment in 2011 created one of its daughters using a different method, partially proving the results of the discovery experiment, and the original experiment was repeated successfully in 2012. The International Union of Pure and Applied Chemistry (IUPAC), however, has made no comment on whether or not the element can be recognized as discovered.

In the periodic table ununseptium is located in the group 17, all previous members of which are halogens. The element is unlikely to be a halogen, however, and will probably show differences, although a few key properties such melting and boiling points and first ionization are expected to follow the periodic trends. While lighter isotopes are agreed in the literature to be very unstable, there are signs that the super-heavy isotopes may be much more stable.

History

Pre-discovery

In 2004 the Joint Institute for Nuclear Research (JINR) team in Dubna, Moscow Oblast, Russia developed a project for the discovery of element 117 (with 117 protons in its nucleus) that required smashing together a berkelium (element 97) target and a calcium (element 20) beam.^[10] However, the team at the Oak Ridge National Laboratory in the United States, the world's only producer of berkelium, refused to provide any, citing a lack of production of the exotic material.^[10] Plans to synthesize element 117 were shelved temporarily in favor of the synthesis of element 118, which was produced by smashing another target (made of californium) with calcium in a Russian–American collaboration.^[11] The Russian team's desire to use an element they could not access was due to the nature of the calcium beam: the isotope of calcium used in the beam, calcium-48, has 20 protons and 28 neutrons. The difference of 8 between the two kinds of nucleons is extremely rare for stable and near-stable atoms: calcium-48 is the lightest stable nucleus with such a difference, while zinc-68 is the second-lightest.^[12] The beam is made in Russia by chemically^[13] extracting the minor quantities of calcium-48 present in Earth's natural calcium from the remaining natural calcium.^[14] Thus the resulting nuclei become heavier and closer to the sought-after island of stability, a concept wherein some super-heavy atoms can be relatively stable. Sufficiently heavy-enough nuclei have not been created as of 2012, however, and, in a table of nuclides, they are usually shown to the left to the "island" rather than on it.^[15]

In 2008 the Americans re-launched a program of berkelium production and the JINR team was contacted.^[10] The 22.2-milligram target was purified and then traveled to Dimitrovgrad, Ulyanovsk Oblast to be fixed on a thin titanium firm. It was then transferred to Dubna where it was installed into the JINR particle accelerator, the world's best for the synthesis of superheavy elements (SHEs).^[16]

Discovery

The experiment began in June 2009 and, in January 2010, scientists at the Flerov Laboratory of Nuclear Reactions announced internally that they had succeeded in detecting the decay of a new element with Z = 117 via two decay chains of an odd-odd isotope (undergoing 6 alpha decays before undergoing a spontaneous fission) and of an odd-even one (3 alpha decays before fission).^[9] On April 9, 2010 an official report was released in the journal Physical Review Letters. It revealed that the isotopes mentioned in the previous chains referred to ²⁹⁴Uus and ²⁹³Uus, formed as follows:^[17]

²⁴⁹
₉₇Bk
+ ⁴⁸
₂₀Ca
→ The element Uus does not exist.* → The element Uus does not exist. + 3 ¹
₀
n
(1 event)

²⁴⁹
₉₇Bk
+ ⁴⁸
₂₀Ca
→ The element Uus does not exist.* → The element Uus does not exist. + 4 ¹
₀
n
(5 events)

Before the synthesis of ununseptium, none of ununseptium's daughter isotopes were known;^[17] thus, there was no basis for an IUPAC discovery claim, much less for its recognition. Ununpentium-289, one of ununseptium's daughters, was created in a different way in 2011, yet it matched the claimed decay properties during the discovery.^[18] The discoverers did not, however, submit a claim for the discovery of ununseptium when IUPAC was reviewing claims on discoveries of trans-copernicium elements.^[19] The Dubna team repeated the experiment in 2012^[20] successfully, thus confirming the synthesis of ununseptium and moving one step closer to having the element officially placed on the periodic table.^[21]

Naming

Using Mendeleev's nomenclature for unnamed and undiscovered elements, ununseptium should be known as eka-astatine or dvi-iodine. In 1979 IUPAC published recommendations according to which the element was to be called ununseptium (with the corresponding symbol of Uus),^[22] a systematic element name as a placeholder, until the discovery of the element is confirmed and a name is decided on. The recommendations are largely ignored among scientists, who call it "element 117," with the symbol of (117) or even simply 117.^[23] No official name has yet been suggested for the element. According to current guidelines from IUPAC, the ultimate name for all new elements should end in "-ium", which means the name for ununseptium may end in -ium, not -ine, even if ununseptium turns out to be a halogen, which traditionally have names ending in "-ine".^[24]

Predicted properties

Nucleus stability and isotopes

A 3D graph of stability of elements vs. number of protons Z and neutrons N, showing a "mountain chain" running diagonally through the graph from the low to high numbers, as well as an "island of stability" at high N and Z. — The recent ununseptium synthesis may be thought of as proof of the existence of the magic "island of stability", according to the discoverers.^[25]

The stability of nuclei decreases greatly with the increase in atomic number after plutonium, the heaviest primordial element, so that all isotopes with an atomic number above 101 decay radioactively with a half-life under a day, with an exception of dubnium-268. No elements with atomic numbers above 82 (after lead) have stable isotopes.^[26] Nevertheless, because of reasons not very well understood yet, there is a slight increased nuclear stability around atomic numbers 110–114, which leads to the appearance of what is known in nuclear physics as the "island of stability". This concept, proposed by University of California professor Glenn Seaborg, explains why superheavy elements last longer than predicted.^[27] Ununseptium is the second-heaviest element of all created so far and is radioactive, having a half-life that appears to be less than one second. Nonetheless, this is still longer than the predicted values used in the discovery report.^[17] The Dubna team believes that the synthesis of the element is direct experimental proof of the existence of the island.^[25]

Calculations using a quantum-tunneling model predict the existence of several isotopes of ununseptium with alpha-decay half-lives up to over 10 ms, culminating at ²⁹⁶Uus (the research ends on ³⁰³Uus).^[28] A more detailed study by the Brazilian Center for Physics Research (CBPF) on the element's isotopes shows similar results (in particular that ²⁹⁶Uus is the most stable isotope in its region),^[a] but goes further up to ³³⁷Uus. In the region neighboring the synthesized isotopes ²⁹³Uus and ²⁹⁴Uus, some isotopes could be slightly more stable than the two that are known, most likely ²⁹⁵Uus and ²⁹⁶Uus. It reveals a general increasing stability trend for isotopes heavier than ³⁰¹Uus, the isotope that has 184 neutrons, considered to be a magic number in physics that is thought to provide extra stability. Beginning with ³¹⁰Uus, the isotopes again begin to be more stable than the synthesized two; ³²⁶Uus has a half-life of over 300 years and the heaviest isotope for which predictions are available, ³³⁷Uus, should have a half-life of about 10¹⁶ years.^[29]^[b]

Atomic, physical

Ununseptium is a member of group 17 in the periodic table, below the five halogens. Every previous group-17 element has seven electrons in its valence shell, forming a valence electron configuration of ns²np⁵. In ununseptium's case, the trend will be continued and the valence electron configuration is predicted to be 7s²7p⁵;^[3] therefore, ununseptium will behave similar to the halogens in many respects. However, notable differences are likely to arise; a largely contributing effect is the spin–orbit (SO) interaction, or, more exactly, subshell splitting.^[31] For many theoretical purposes, the configuration may be represented to reflect the 7p-subshell split as 7s²7p_1/2²7p_3/2³.

The melting and boiling points of ununseptium cannot be considered to be definitely defined; although it can be taken for granted that ununseptium is to be a solid under standard conditions. An early paper predicted the points to be about 350–500 °C and 550 °C,^[3] exceeding the astatine (and all preceding) values, following periodic trends, which means that the element should be a solid in its free form; a later paper, however, set the boiling point to be 345 °C.^[32]

The first ionization energy (the energy required to remove an electron from an atom) is predicted to be 7.7 eV, lower than that of the previous halogens, again following the trend.^[3] Ununseptium is also in line with its neighbors in having lowest electron affinity (energy released when an electron is added to the atom) in the group. Notably the electron of the monoelectronic ion (oxidized so that it has only one electron) moves so fast that they have a mass of 1.9 compared to a non-moving electron, a feature coming from the relativistic effects (compare: 1.27 for astatine, 1.08 for iodine, etc.).^[31]

Chemical

The previous members of the group commonly accept another electron to achieve a stable noble-gas electronic configuration, having eight electrons (octet) in its valence shell, which is the minimum-energy configuration in which the outer electrons are tightly bound.^[33] This ability weakens going down the group: As mentioned, ununseptium is the least willing to accept an electron among the group 17 elements (notice also that astatine already forms a positive oxidation state in its hydride). In fact, out of the oxidation states the element is to form, -1 is the least common.^[3]

There is another opportunity for ununseptium to complete the octet—to form a covalent bond. Accordingly, two ununseptium atoms when meeting together are expected to form a Uus–Uus bond to give diatomic molecules, just like the halogens. The sigma bonding shows a great antibonding character in the At₂ molecule; ununseptium is predicted to continue the trend and a strong pi character should be seen in the bonding of Uus₂.^[3]^[34] Similarly to Uus₂, the molecule UusCl should be bonded via a single pi bond.^[34]

Aside from the mentioned −1 state, three more are predicted: +5, +3, and +1, with the latter especially more stable because of the destabilization of the three outermost 7p_3/2 electrons^[3] (similarly to astatine^[31]). The +3 state may resemble that of Au³⁺ in ion-exchange behavior in a halide environment;^[3] simple extrapolation of the destabilization of the 7p_3/2 electrons suggests this oxidation state should be also important. The +5 state is predicted to also be uncommon, as the 7p_1/2 electrons are (oppositely) stabilized.^[3]

The simplest ununseptium compound is its monohydride, UusH. The bonding is provided by the 7p_3/2 electron of ununseptium and 1s_1/2 electron of hydrogen. Non-bonding nature of the 7p_1/2 spinor comes from the the unwillingness of ununseptium to form purely alpha or pi bonds. Since the ununseptium p electrons are two-third sigma, the bond is only two-third as atrong as it would be if ununseptium did not feature SO interactions.^[35] In general, the molecule follows the trend for halogen hydrides, showing an increase in bond length and a decrease in dissociation energy as compared to AtH.^[3]

The molecule UusF should be the most tightly bound of all interhalogen monofluorides.^[34] The molecule UusF₃ should not have the T-shaped geometry seen in other interhalogen trifluorides.^[34] In the molecule UutUus, the more electronegative atom is notably predicted to be the ununtrium atom, the opposite of what periodic trends would predict.^[34]

Notes

^ This research gives the total half-lives, not just the alpha-decay half-lives.
^ Half-lives of the six heaviest isotopes studied in the report, ³³²Uus through ³³⁷Uus, were predicted by the report to exceed 80 million years,^[29] the half-life of ²⁴⁴Pu,^[30] the least stable primordial nuclide; thus, if ever created in sufficient quantity, these isotopes could have survived until the present day.

References

^ Ritter, Malcolm (June 9, 2016). "Periodic table elements named for Moscow, Japan, Tennessee". Associated Press. Retrieved December 19, 2017.
^ ^a ^b Fricke, Burkhard (1975). "Superheavy elements: a prediction of their chemical and physical properties". Recent Impact of Physics on Inorganic Chemistry. Structure and Bonding. 21: 89–144. doi:10.1007/BFb0116498. ISBN 978-3-540-07109-9. Retrieved 4 October 2013.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Hoffman, Darleane C.; Lee, Diana M.; Pershina, Valeria (2006). "Transactinides and the future elements". In Morss; Edelstein, Norman M.; Fuger, Jean (eds.). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer Science+Business Media. ISBN 978-1-4020-3555-5.
^ ^a ^b ^c ^d Bonchev, D.; Kamenska, V. (1981). "Predicting the Properties of the 113–120 Transactinide Elements". Journal of Physical Chemistry. 85 (9): 1177–1186. doi:10.1021/j150609a021.
^ ^a ^b ^c Chang, Zhiwei; Li, Jiguang; Dong, Chenzhong (2010). "Ionization Potentials, Electron Affinities, Resonance Excitation Energies, Oscillator Strengths, And Ionic Radii of Element Uus (Z = 117) and Astatine". J. Phys. Chem. A. 2010 (114): 13388–94. Bibcode:2010JPCA..11413388C. doi:10.1021/jp107411s.
^ ^a ^b Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
^ Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch. E.; et al. (2014). "⁴⁸Ca+²⁴⁹Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying ²⁷⁰Db and Discovery of ²⁶⁶Lr". Physical Review Letters. 112 (17): 172501. Bibcode:2014PhRvL.112q2501K. doi:10.1103/PhysRevLett.112.172501. PMID 24836239.
^ Oganessian, Yu. Ts.; et al. (2013). "Experimental studies of the ²⁴⁹Bk + ⁴⁸Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope ²⁷⁷Mt". Physical Review C. 87 (5): 054621. Bibcode:2013PhRvC..87e4621O. doi:10.1103/PhysRevC.87.054621.
^ ^a ^b Recommendations: 31st meeting, PAC for Nuclear Physics
^ ^a ^b ^c Gabage, Bill (2010). "Synthesis of a new element with atomic number Z=117". webelements.com.
^ Oganessian, Yu. Ts.; et al. (2002). "Results from the first ²⁴⁹Cf+⁴⁸Ca experiment" (PDF). JINR Communication. JINR, Dubna. {{cite journal}}: Explicit use of et al. in: |author= (help)
^ G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ Jepson, B. E.; Shockley, G. C. (1984). "Calcium hydroxide isotope effect in calcium isotope enrichment by ion exchange". Separation Science and Technology. 19 (2–3): 173–181. Retrieved 2012-07-07. {{cite journal}}: Cite has empty unknown parameter: |1= (help)
^ "Ununseptium – the 117th element". RIA Novosti. 2009-10-28. Retrieved 2012-07-07.
^ "Universal Nuclide Chart". Nucleonica. Institute for Transuranium Elements. 2007–2012. Retrieved 2012-07-03.
^ Lauren Schenkman (2010). "Discovery of 'Missing' Element 117 Hints at Stable Isotopes to Come". Ukrainian Science Club. Retrieved 2012-06-28.
^ ^a ^b ^c ^d Yu. Ts. Oganessian; et al. (2010). "Synthesis of a New Element with Atomic Number Z=117". Phys. Rev. Lett. (104). {{cite journal}}: Explicit use of et al. in: |author= (help); Text "10.1103/PhysRevLett.104.142502" ignored (help)
^ Template:Ru icon "В лабораториях ОИЯИ. Возвращение к дубнию". JINR. 2011. {{cite web}}: Unknown parameter |trans_title= ignored (|trans-title= suggested) (help)
^ Barber, Robert C.; Karol, Paul J.; Nakahara, Hiromichi; Vardaci, Emanuele; Vogt, Erich W. (2011). "Discovery of the elements with atomic numbers greater than or equal to 113 (IUPAC Technical Report)". Pure and Applied Chemistry: 1. doi:10.1351/PAC-REP-10-05-01.
^ Template:Ru icon "Эксперимент по синтезу 117-го элемента получает продолжение". JINR. 2012. {{cite web}}: Unknown parameter |trans_title= ignored (|trans-title= suggested) (help)
^ "Russian Scientists Confirm 117th Element". RIA Novosti. 2012-06-25. Retrieved 2012-07-05.
^ Chatt, J. (1979). "Recommendations for the Naming of Elements of Atomic Numbers Greater than 100". Pure Appl. Chem. 51 (2): 381–384. doi:10.1351/pac197951020381.
^ Folden, Cody (2009-01-31). "The Heaviest Elements in the Universe" (PDF). Saturday Morning Physics at Texas A&M. Retrieved 2012-03-09.
^ Koppenol, W. H. (2002). "Naming of new elements (IUPAC Recommendations 2002)" (PDF). Pure and Applied Chemistry. 74 (5): 787. doi:10.1351/pac200274050787.
^ ^a ^b Template:Ru icon "Синтез нового 117-го элемента". JINR. 2010. {{cite web}}: Unknown parameter |trans_title= ignored (|trans-title= suggested) (help)
^ Marcillac, Pierre de (2003). "Experimental detection of α-particles from the radioactive decay of natural bismuth". Nature. 422 (6934): 876–878. Bibcode:2003Natur.422..876D. doi:10.1038/nature01541. PMID 12712201. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
^ Kulik, Glenn D. (2002). Van Nostrand's scientific encyclopedia (9 ed.). Wiley-Interscience. ISBN 978-0-471-33230-5. OCLC 223349096. {{cite book}}: |first2= missing |last2= (help); More than one of |last1= and |last= specified (help)
^ Chowdhury, Roy P.; Samanta, C.; Basu, D. N. (2008). "Search for long lived heaviest nuclei beyond the valley of stability". Physical Reviews C. 77 (4): 044603. Bibcode:2008PhRvC..77d4603C. doi:10.1103/PhysRevC.77.044603.
^ ^a ^b Duarte, S. B.; et al. (2004). Half-life prediction for decay modes for superheavy nuclei (Report). Centro Brasiliero de Pesquisas Físicas. ISSN 0029-3865. {{cite report}}: Explicit use of et al. in: |author= (help)
^ G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ ^a ^b ^c Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/978-1-4020-9975-5_2, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/978-1-4020-9975-5_2 instead.
^ Takahashi, N. (2002). "Boiling points of the superheavy elements 117 and 118". Journal of Radioanalytical and Nuclear Chemistry. 251 (2): 299–301. doi:10.1023/A:1014880730282.
^ Bader, Richard F.W. "An Introduction to the Electronic Structure of Atoms and Molecules". McMaster University. Retrieved 2008-01-18.
^ ^a ^b ^c ^d ^e Leszczynski, J. (2010). Relativisic Methods for Chemists. Springer Science+Business Media. pp. 84, 504. doi:10.1007/9781402099755. ISBN 9781402099748.
^ Han, Y. K.; Bae, C.; Son, S. K.; Lee, Y. S. (2000). "Spin-orbit effects on the transactinide p-block element monohydrides MH (M=element 113-118)". Journal of Chemical Physics. 112 (6): 2684–2691.{{cite journal}}: CS1 maint: multiple names: authors list (link)

Reid, Tim (2007). "Superheavy elements: Finding the right ingredients". Nature China. doi:10.1038/nchina.2007.186.
Eric Scerri, The Periodic Table, Its Story and Its Significance, Oxford University Press, 2007

External links

[29] This research gives the total half-lives, not just the alpha-decay half-lives.

[32] Half-lives of the six heaviest isotopes studied in the report, ³³²Uus through ³³⁷Uus, were predicted by the report to exceed 80 million years,^[29] the half-life of ²⁴⁴Pu,^[30] the least stable primordial nuclide; thus, if ever created in sufficient quantity, these isotopes could have survived until the present day.

[1] Ritter, Malcolm (June 9, 2016). "Periodic table elements named for Moscow, Japan, Tennessee". Associated Press. Retrieved December 19, 2017.

[Fricke1975-2] Fricke, Burkhard (1975). "Superheavy elements: a prediction of their chemical and physical properties". Recent Impact of Physics on Inorganic Chemistry. Structure and Bonding. 21: 89–144. doi:10.1007/BFb0116498. ISBN 978-3-540-07109-9. Retrieved 4 October 2013.

[Haire-3] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m ⁿ Hoffman, Darleane C.; Lee, Diana M.; Pershina, Valeria (2006). "Transactinides and the future elements". In Morss; Edelstein, Norman M.; Fuger, Jean (eds.). The Chemistry of the Actinide and Transactinide Elements (3rd ed.). Dordrecht, The Netherlands: Springer Science+Business Media. ISBN 978-1-4020-3555-5.

[B&K-4] Bonchev, D.; Kamenska, V. (1981). "Predicting the Properties of the 113–120 Transactinide Elements". Journal of Physical Chemistry. 85 (9): 1177–1186. doi:10.1021/j150609a021.

[Chang-5] Chang, Zhiwei; Li, Jiguang; Dong, Chenzhong (2010). "Ionization Potentials, Electron Affinities, Resonance Excitation Energies, Oscillator Strengths, And Ionic Radii of Element Uus (Z = 117) and Astatine". J. Phys. Chem. A. 2010 (114): 13388–94. Bibcode:2010JPCA..11413388C. doi:10.1021/jp107411s.

[NUBASE2020-6] Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

[266Lr-7] Khuyagbaatar, J.; Yakushev, A.; Düllmann, Ch. E.; et al. (2014). "⁴⁸Ca+²⁴⁹Bk Fusion Reaction Leading to Element Z=117: Long-Lived α-Decaying ²⁷⁰Db and Discovery of ²⁶⁶Lr". Physical Review Letters. 112 (17): 172501. Bibcode:2014PhRvL.112q2501K. doi:10.1103/PhysRevLett.112.172501. PMID 24836239.

[277Mt-8] Oganessian, Yu. Ts.; et al. (2013). "Experimental studies of the ²⁴⁹Bk + ⁴⁸Ca reaction including decay properties and excitation function for isotopes of element 117, and discovery of the new isotope ²⁷⁷Mt". Physical Review C. 87 (5): 054621. Bibcode:2013PhRvC..87e4621O. doi:10.1103/PhysRevC.87.054621.

[E117-9] Recommendations: 31st meeting, PAC for Nuclear Physics

[elements-10] Gabage, Bill (2010). "Synthesis of a new element with atomic number Z=117". webelements.com.

[pp2002-11] Oganessian, Yu. Ts.; et al. (2002). "Results from the first ²⁴⁹Cf+⁴⁸Ca experiment" (PDF). JINR Communication. JINR, Dubna. {{cite journal}}: Explicit use of et al. in: |author= (help)

[12] G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.{{cite journal}}: CS1 maint: multiple names: authors list (link)

[13] Jepson, B. E.; Shockley, G. C. (1984). "Calcium hydroxide isotope effect in calcium isotope enrichment by ion exchange". Separation Science and Technology. 19 (2–3): 173–181. Retrieved 2012-07-07. {{cite journal}}: Cite has empty unknown parameter: |1= (help)

[14] "Ununseptium – the 117th element". RIA Novosti. 2009-10-28. Retrieved 2012-07-07.

[15] "Universal Nuclide Chart". Nucleonica. Institute for Transuranium Elements. 2007–2012. Retrieved 2012-07-03.

[Ukraine-16] Lauren Schenkman (2010). "Discovery of 'Missing' Element 117 Hints at Stable Isotopes to Come". Ukrainian Science Club. Retrieved 2012-06-28.

[117s-17] Yu. Ts. Oganessian; et al. (2010). "Synthesis of a New Element with Atomic Number Z=117". Phys. Rev. Lett. (104). {{cite journal}}: Explicit use of et al. in: |author= (help); Text "10.1103/PhysRevLett.104.142502" ignored (help)

[18] Template:Ru icon "В лабораториях ОИЯИ. Возвращение к дубнию". JINR. 2011. {{cite web}}: Unknown parameter |trans_title= ignored (|trans-title= suggested) (help)

[19] Barber, Robert C.; Karol, Paul J.; Nakahara, Hiromichi; Vardaci, Emanuele; Vogt, Erich W. (2011). "Discovery of the elements with atomic numbers greater than or equal to 113 (IUPAC Technical Report)". Pure and Applied Chemistry: 1. doi:10.1351/PAC-REP-10-05-01.

[20] Template:Ru icon "Эксперимент по синтезу 117-го элемента получает продолжение". JINR. 2012. {{cite web}}: Unknown parameter |trans_title= ignored (|trans-title= suggested) (help)

[21] "Russian Scientists Confirm 117th Element". RIA Novosti. 2012-06-25. Retrieved 2012-07-05.

[iupac-22] Chatt, J. (1979). "Recommendations for the Naming of Elements of Atomic Numbers Greater than 100". Pure Appl. Chem. 51 (2): 381–384. doi:10.1351/pac197951020381.

[Folden-23] Folden, Cody (2009-01-31). "The Heaviest Elements in the Universe" (PDF). Saturday Morning Physics at Texas A&M. Retrieved 2012-03-09.

[24] Koppenol, W. H. (2002). "Naming of new elements (IUPAC Recommendations 2002)" (PDF). Pure and Applied Chemistry. 74 (5): 787. doi:10.1351/pac200274050787.

[IS-25] Template:Ru icon "Синтез нового 117-го элемента". JINR. 2010. {{cite web}}: Unknown parameter |trans_title= ignored (|trans-title= suggested) (help)

[26] Marcillac, Pierre de (2003). "Experimental detection of α-particles from the radioactive decay of natural bismuth". Nature. 422 (6934): 876–878. Bibcode:2003Natur.422..876D. doi:10.1038/nature01541. PMID 12712201. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)

[27] Kulik, Glenn D. (2002). Van Nostrand's scientific encyclopedia (9 ed.). Wiley-Interscience. ISBN 978-0-471-33230-5. OCLC 223349096. {{cite book}}: |first2= missing |last2= (help); More than one of |last1= and |last= specified (help)

[prc08ADNDT08-28] Chowdhury, Roy P.; Samanta, C.; Basu, D. N. (2008). "Search for long lived heaviest nuclei beyond the valley of stability". Physical Reviews C. 77 (4): 044603. Bibcode:2008PhRvC..77d4603C. doi:10.1103/PhysRevC.77.044603.

[Brazil-30] Duarte, S. B.; et al. (2004). Half-life prediction for decay modes for superheavy nuclei (Report). Centro Brasiliero de Pesquisas Físicas. ISSN 0029-3865. {{cite report}}: Explicit use of et al. in: |author= (help)

[31] G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.{{cite journal}}: CS1 maint: multiple names: authors list (link)

[Springer-33] Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi:10.1007/978-1-4020-9975-5_2, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi=10.1007/978-1-4020-9975-5_2 instead.

[34] Takahashi, N. (2002). "Boiling points of the superheavy elements 117 and 118". Journal of Radioanalytical and Nuclear Chemistry. 251 (2): 299–301. doi:10.1023/A:1014880730282.

[35] Bader, Richard F.W. "An Introduction to the Electronic Structure of Atoms and Molecules". McMaster University. Retrieved 2008-01-18.

[POL-36] Leszczynski, J. (2010). Relativisic Methods for Chemists. Springer Science+Business Media. pp. 84, 504. doi:10.1007/9781402099755. ISBN 9781402099748.

[37] Han, Y. K.; Bae, C.; Son, S. K.; Lee, Y. S. (2000). "Spin-orbit effects on the transactinide p-block element monohydrides MH (M=element 113-118)". Journal of Chemical Physics. 112 (6): 2684–2691.{{cite journal}}: CS1 maint: multiple names: authors list (link)

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@@ Line 34: / Line 34: @@
 Calculations using a quantum-tunneling model predict the existence of several isotopes of ununseptium with alpha-decay half-lives up to over 10&nbsp;ms, culminating at <sup>296</sup>Uus (the research ends on <sup>303</sup>Uus).<ref name=prc08ADNDT08>{{cite journal|journal=Physical Reviews C|volume=77|page=044603|year=2008|title=Search for long lived heaviest nuclei beyond the valley of stability|first1=Roy P.|last1=Chowdhury |first2=C. |last2=Samanta |first3= D. N. |last3=Basu|doi=10.1103/PhysRevC.77.044603|bibcode = 2008PhRvC..77d4603C|issue=4}}</ref> A more detailed study by the Brazilian Center for Physics Research ([[CBPF]]) on the element's [[isotopes of ununseptium|isotopes]] shows similar results (in particular that <sup>296</sup>Uus is the most stable isotope in its region),{{efn|This research gives the total half-lives, not just the alpha-decay half-lives.}} but goes further up to <sup>337</sup>Uus. In the region neighboring the synthesized isotopes <sup>293</sup>Uus and <sup>294</sup>Uus, some isotopes could be slightly more stable than the two that are known, most likely <sup>295</sup>Uus and <sup>296</sup>Uus. It reveals a general increasing stability trend for isotopes heavier than <sup>301</sup>Uus, the isotope that has 184 neutrons, considered to be a [[magic number (physics)|magic number]] in physics that is thought to provide extra stability. Beginning with <sup>310</sup>Uus, the isotopes again begin to be more stable than the synthesized two; <sup>326</sup>Uus has a half-life of over 300 years and the heaviest isotope for which predictions are available, <sup>337</sup>Uus, should have a half-life of about 10<sup>16</sup> years.<ref name="Brazil">{{cite report|author=Duarte, S. B., ''et al.''|title=Half-life prediction for decay modes for superheavy nuclei|publisher=Centro Brasiliero de Pesquisas Físicas|year=2004|issn=0029-3865}}</ref>{{efn|Half-lives of the six heaviest isotopes studied in the report, <sup>332</sup>Uus through <sup>337</sup>Uus, were predicted by the report to exceed 80 million years,<ref name="Brazil"/> the half-life of <sup>244</sup>Pu,<ref>{{cite journal |author=G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon |year=2003 |title=The NUBASE evaluation of nuclear and decay properties |url=http://www.nndc.bnl.gov/amdc/nubase/Nubase2003.pdf |journal=[[Nuclear Physics A]] |volume=729 |issue= |pages=3–128 |doi=10.1016/j.nuclphysa.2003.11.001 |bibcode=2003NuPhA.729....3A}}</ref> the least stable primordial nuclide; thus, if ever created in sufficient quantity, these isotopes could have survived until the present day.}}
-===Atomic, physical, and chemical===
+===Atomic, physical===
-Ununseptium is a member of group 17 in the [[periodic table]], below the five [[halogen]]s. Every previous group-17 element has seven electrons in its valence shell, forming a [[valence electron]] configuration of ns<sup>2</sup>np<sup>5</sup>. In ununseptium's case, the trend will be continued and the valence electron configuration is predicted to be 7s<sup>2</sup>7p<sup>5</sup>;<ref name="Haire"/> therefore, ununseptium will behave similar to the halogens in many respects. However, notable differences are likely to arise; a largely contributing effect is the [[spin–orbit interaction|spin–orbit (SO) interaction]].
+Ununseptium is a member of group 17 in the [[periodic table]], below the five [[halogen]]s. Every previous group-17 element has seven electrons in its valence shell, forming a [[valence electron]] configuration of ns<sup>2</sup>np<sup>5</sup>. In ununseptium's case, the trend will be continued and the valence electron configuration is predicted to be 7s<sup>2</sup>7p<sup>5</sup>;<ref name="Haire"/> therefore, ununseptium will behave similar to the halogens in many respects. However, notable differences are likely to arise; a largely contributing effect is the [[spin–orbit interaction|spin–orbit (SO) interaction]], or, more exactly, subshell splitting.<ref name="Springer"/> For many theoretical purposes, the configuration may be represented to reflect the 7p-subshell split as 7s<sup>2</sup>7p<sub>1/2</sub><sup>2</sup>7p<sub>3/2</sub><sup>3</sup>.
-The melting point of ununseptium is predicted to be 350–500&nbsp;°C<ref name="Haire"/> and the boiling point should be about 550&nbsp;°C,<ref name="Haire"/> exceeding the astatine (and all preceding) values, following periodic trends, which means that the element should be a solid in its free form. The first [[ionization energy]] (the energy required to remove an electron from an atom) is predicted to be 7.7&nbsp;eV, lower than that of the previous halogens, again following the trend.<ref name="Haire"/>
+The melting and boiling points of ununseptium cannot be considered to be definitely defined; although it can be taken for granted that ununseptium is to be a solid under [[standard conditions]]. An early paper predicted the points to be about 350–500&nbsp;°C and 550&nbsp;°C,<ref name="Haire"/> exceeding the astatine (and all preceding) values, following periodic trends, which means that the element should be a solid in its free form; a later paper, however, set the boiling point to be 345&nbsp;°C.<ref>{{cite journal|journal=Journal of Radioanalytical and Nuclear Chemistry|volume=251|issue=2|year=2002|pages=299–301|title=Boiling points of the superheavy elements 117 and 118|first=N. |last=Takahashi|doi=10.1023/A:1014880730282}}</ref>
+The first [[ionization energy]] (the energy required to remove an electron from an atom) is predicted to be 7.7&nbsp;eV, lower than that of the previous halogens, again following the trend.<ref name="Haire"/> Ununseptium is also in line with its neighbors in having lowest [[electron affinity]] (energy released when an electron is added to the atom) in the group. Notably the electron of the monoelectronic ion (oxidized so that it has only one electron) moves so fast that they have a mass of 1.9 compared to a non-moving electron, a feature coming from the relativistic effects (compare: 1.27 for astatine, 1.08 for iodine, etc.).<ref name="Springer"/>
-The previous members of the group commonly accept another electron to achieve a stable [[noble gas|noble-gas]] [[electronic configuration]], having eight electrons ([[octet rule|octet]]) in its valence shell, which is the minimum-energy configuration in which the outer electrons are tightly bound.<ref>{{cite web|last=Bader|first=Richard F.W|url=http://miranda.chemistry.mcmaster.ca/esam/|title=An Introduction to the Electronic Structure of Atoms and Molecules|publisher=McMaster University|accessdate=2008-01-18}}</ref> A neutral halogen atom, however, has seven, so it attracts one another from other atoms, with such ability weakening going down the group. Ununseptium is expectedly in line with its neighbors, being predicted to have the lowest [[electron affinity]] (energy released when an electron is added to the atom) in the group.
+===Chemical===
-There is another opportunity for ununseptium to complete the octet – to form a covalent bond. And two ununseptium atoms when meeting together are expected to form a Uus–Uus bond to give [[diatomic molecule]]s, just like the halogens. The sigma bonding shows a great antibonding character in the At<sub>2</sub> molecule; ununseptium is predicted to continue the trend and a strong pi character should be seen in the bonding of Uus<sub>2</sub>,<ref name="Haire"/><ref name="POL"/> coming from SO interactions.
+The previous members of the group commonly accept another electron to achieve a stable [[noble gas|noble-gas]] [[electronic configuration]], having eight electrons ([[octet rule|octet]]) in its valence shell, which is the minimum-energy configuration in which the outer electrons are tightly bound.<ref>{{cite web|last=Bader|first=Richard F.W|url=http://miranda.chemistry.mcmaster.ca/esam/|title=An Introduction to the Electronic Structure of Atoms and Molecules|publisher=McMaster University|accessdate=2008-01-18}}</ref> This ability weakens going down the group: As mentioned, ununseptium is the least willing to accept an electron among the group 17 elements (notice also that astatine already forms a positive oxidation state in its [[astatine hydride|hydride]]). In fact, out of the oxidation states the element is to form, -1 is the least common.<ref name="Haire"/>
-Achieving the octet configuration by forming a negative oxidation state, however, becomes less common going down the group, with astatine already forming a positive oxidation state in its [[astatine hydride|hydride]]. This trend continues for ununseptium: the −1 state is predicted to be the least stable of the predicted four, with +5, +3, and especially +1 being more stable because of the destabilization of the three outermost 7p<sub>3/2</sub> electrons. The +5 state is predicted to also be uncommon, as the 7p<sub>1/2</sub> electrons are (oppositely) stabilized. The +3 state may resemble that of Au<sup>3+</sup> in ion-exchange behavior in a [[halide]] environment.<ref name="Haire"/>
+There is another opportunity for ununseptium to complete the octet—to form a covalent bond. Accordingly, two ununseptium atoms when meeting together are expected to form a Uus–Uus bond to give [[diatomic molecule]]s, just like the halogens. The sigma bonding shows a great antibonding character in the At<sub>2</sub> molecule; ununseptium is predicted to continue the trend and a strong pi character should be seen in the bonding of Uus<sub>2</sub>.<ref name="Haire"/><ref name="POL"/> Similarly to Uus<sub>2</sub>, the molecule UusCl should be bonded via a single pi bond.<ref name="POL"/>
-Similarly to Uus<sub>2</sub>, the molecule UusCl should be bonded via a single pi bond.<ref name="POL"/> The molecule UusF should be the most tightly bound of all [[interhalogen]] monofluorides.<ref name="POL">{{cite book|url=http://books.google.ru/books?id=QbDEC3oL7uAC&pg=PA127&lpg=PA127&dq=Re+trend+HI+HAt+H117&source=bl&ots=S4hksKcjBK&sig=bFbp0ra8N1qSHFVR_p-m2MV65hI&hl=ru&sa=X&ei=OsftT8G3IcSq-Abi2IS3Dg&ved=0CEsQ6AEwAA#v=onepage&q=117&f=false|pages=84, 504|title=Relativisic Methods for Chemists|publisher=Springer Science+Business Media|author=Leszczynski, J.|isbn=9781402099748|doi=10.1007/9781402099755|year=2010}}</ref> The halogen hydrides show an increase in bond length and a decrease in dissociation energy; the molecule UusH is thought to continue the trend.<ref name="Haire"/> The molecule UusF<sub>3</sub> should not have the T-shaped geometry seen in other interhalogen trifluorides.<ref name="POL"/> In the molecule [[ununtrium|Uut]]Uus, the more [[electronegativity|electronegative]] atom is notably predicted to be the ununtrium atom, the opposite of what periodic trends would predict.<ref name="POL"/>
+Aside from the mentioned −1 state, three more are predicted: +5, +3, and +1, with the latter especially more stable because of the destabilization of the three outermost 7p<sub>3/2</sub> electrons<ref name="Haire"/> (similarly to astatine<ref name="Springer">{{cite doi|10.1007/978-1-4020-9975-5_2|p=79}}</ref>). The +3 state may resemble that of Au<sup>3+</sup> in ion-exchange behavior in a [[halide]] environment;<ref name="Haire"/> simple extrapolation of the destabilization of the 7p<sub>3/2</sub> electrons suggests this oxidation state should be also important. The +5 state is predicted to also be uncommon, as the 7p<sub>1/2</sub> electrons are (oppositely) stabilized.<ref name="Haire"/>
+The simplest ununseptium compound is its monohydride, UusH. The bonding is provided by the 7p<sub>3/2</sub> electron of ununseptium and 1s<sub>1/2</sub> electron of hydrogen. Non-bonding nature of the 7p<sub>1/2</sub> spinor comes from the the unwillingness of ununseptium to form purely alpha or pi bonds. Since the ununseptium p electrons are two-third sigma, the bond is only two-third as atrong as it would be if ununseptium did not feature SO interactions.<ref>{{cite journal|journal=Journal of Chemical Physics|title=Spin-orbit effects on the transactinide p-block element monohydrides MH (M=element 113-118)|author=Han, Y. K.; Bae, C.; Son, S. K.; Lee, Y. S.|volume=112|issue=6|pages=2684-2691|year=2000}}</ref> In general, the molecule follows the trend for halogen hydrides, showing an increase in bond length and a decrease in dissociation energy as compared to AtH.<ref name="Haire"/>
+The molecule UusF should be the most tightly bound of all [[interhalogen]] monofluorides.<ref name="POL">{{cite book|url=http://books.google.ru/books?id=QbDEC3oL7uAC&pg=PA127&lpg=PA127&dq=Re+trend+HI+HAt+H117&source=bl&ots=S4hksKcjBK&sig=bFbp0ra8N1qSHFVR_p-m2MV65hI&hl=ru&sa=X&ei=OsftT8G3IcSq-Abi2IS3Dg&ved=0CEsQ6AEwAA#v=onepage&q=117&f=false|pages=84, 504|title=Relativisic Methods for Chemists|publisher=Springer Science+Business Media|author=Leszczynski, J.|isbn=9781402099748|doi=10.1007/9781402099755|year=2010}}</ref>  The molecule UusF<sub>3</sub> should not have the T-shaped geometry seen in other interhalogen trifluorides.<ref name="POL"/> In the molecule [[ununtrium|Uut]]Uus, the more [[electronegativity|electronegative]] atom is notably predicted to be the ununtrium atom, the opposite of what periodic trends would predict.<ref name="POL"/>
 <!--
 An ununseptium atom should have an [[ionic radius|radius]] of 58&nbsp;pm for the heptapositive ion (Uus<sup>7+</sup>) and 80&nbsp;pm for the tetrapositive ion (Uus<sup>4+</sup>).