Editing Ununennium (section)

==Predicted properties==

===Nuclear stability and isotopes===
[[File:Island of Stability derived from Zagrebaev.svg|center|thumb|alt=A 2D graph with rectangular cells colored in black-and-white colors, spanning from the llc to the urc, with cells mostly becoming lighter closer to the latter|A chart of nuclide stability as used by the Dubna team in 2010. Characterized isotopes are shown with borders. Beyond element 118 (oganesson, the last known element), the line of known nuclides is expected to rapidly enter a region of instability, with no half-lives over one microsecond after element 121. The white ring encloses the predicted location of the island of stability.{{sfn|Zagrebaev|Karpov|Greiner|2013}}|400x400px]]

[[File:Next proton shell.svg|class=skin-invert-image|thumb|right|upright=1.2|Orbitals with high [[azimuthal quantum number]] are raised in energy, eliminating what would otherwise be a gap in orbital energy corresponding to a closed proton shell at [[flerovium|element 114]], as shown in the left diagram which does not take this effect into account. This raises the next proton shell to the region around [[unbinilium|element 120]], as shown in the right diagram, potentially increasing the half-lives of element 119 and 120 isotopes.<ref name="Kratz">{{cite conference |last1=Kratz |first1=J. V. |date=5 September 2011 |title=The Impact of Superheavy Elements on the Chemical and Physical Sciences |url=http://tan11.jinr.ru/pdf/06_Sep/S_1/02_Kratz.pdf |conference=4th International Conference on the Chemistry and Physics of the Transactinide Elements |access-date=27 August 2013 |archive-date=9 October 2022 |archive-url=https://ghostarchive.org/archive/20221009/http://tan11.jinr.ru/pdf/06_Sep/S_1/02_Kratz.pdf |url-status=live }}</ref>]]
The stability of nuclei decreases greatly with the increase in atomic number after [[curium]], element 96, whose half-life is four orders of magnitude longer than that of any currently known higher-numbered element. All isotopes with an atomic number above [[mendelevium|101]] undergo [[radioactive decay]] with half-lives of less than 30 hours. No elements with atomic numbers above 82 (after [[lead]]) have stable isotopes.<ref>{{cite journal |last1=de Marcillac |first1=Pierre |last2=Coron |first2=Noël |last3=Dambier |first3=Gérard |last4=Leblanc |first4=Jacques |last5=Moalic |first5=Jean-Pierre |display-authors=3 |date=2003 |title=Experimental detection of α-particles from the radioactive decay of natural bismuth |journal=Nature |volume=422 |pages=876–878 |pmid=12712201 |doi=10.1038/nature01541 |issue=6934 |bibcode=2003Natur.422..876D |s2cid=4415582 }}</ref> Nevertheless, for reasons not yet well understood, there is a slight increase of nuclear stability around atomic numbers [[darmstadtium|110]]–[[flerovium|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, Berkeley|University of California]] professor [[Glenn Seaborg]], explains why superheavy elements last longer than predicted.<ref>{{cite book |title=Van Nostrand's scientific encyclopedia |first1=Glenn D. |last1=Considine |first2=Peter H. |last2=Kulik |publisher=Wiley-Interscience |date=2002 |edition=9th |isbn=978-0-471-33230-5 |oclc=223349096 }}</ref>

The alpha-decay half-lives predicted for <sup>291–307</sup>Uue are on the order of microseconds. The longest alpha-decay half-life predicted is ~485 microseconds for the isotope <sup>294</sup>Uue.<ref name="npa07">{{cite journal|journal=Nucl. Phys. A|volume=789|issue=1–4|pages=142–154|title=Predictions of alpha decay half lives of heavy and superheavy elements|author=Chowdhury, P. Roy|author2=Samanta, C. |author3=Basu, D. N. |name-list-style=amp |doi=10.1016/j.nuclphysa.2007.04.001 |bibcode=2007NuPhA.789..142S |arxiv=nucl-th/0703086 |year=2007 |citeseerx=10.1.1.264.8177 |s2cid=7496348}}</ref><ref>{{cite journal |journal=Phys. Rev. C |volume=77 |issue=4 |at=044603 |title=Search for long lived heaviest nuclei beyond the valley of stability |author=Chowdhury, P. Roy |author2=Samanta, C. |author3=Basu, D. N. |name-list-style=amp |doi=10.1103/PhysRevC.77.044603 |bibcode=2008PhRvC..77d4603C |arxiv=0802.3837 |year=2008 |s2cid=119207807}}</ref><ref>{{cite journal|journal=Atomic Data and Nuclear Data Tables|volume=94|issue=6 |pages=781–806|title=Nuclear half-lives for α -radioactivity of elements with 100 ≤ Z ≤ 130 |author=Chowdhury, P. Roy |author2=Samanta, C. |author3=Basu, D. N. |name-list-style=amp |doi=10.1016/j.adt.2008.01.003 |bibcode=2008ADNDT..94..781C |arxiv=0802.4161 |year=2008|s2cid=96718440 }}</ref> When factoring in all decay modes, the predicted half-lives drop further to only tens of microseconds.<ref name="Haire" /><ref name="Hofmann" /> Some heavier isotopes may be more stable; Fricke and Waber predicted <sup>315</sup>Uue to be the most stable ununennium isotope in 1971.<ref name="Fricke1971" /> This has consequences for the synthesis of ununennium, as isotopes with half-lives below one microsecond would decay before reaching the detector, and the heavier isotopes cannot be synthesised by the collision of any known usable target and projectile nuclei.<ref name="Haire" /><ref name="Hofmann" /> Nevertheless, new theoretical models show that the expected gap in energy between the [[nuclear shell model|proton orbitals]] 2f<sub>7/2</sub> (filled at element 114) and 2f<sub>5/2</sub> (filled at element 120) is smaller than expected, so that element 114 no longer appears to be a stable spherical closed nuclear shell, and this energy gap may increase the stability of elements 119 and 120. The next [[doubly magic]] nucleus is now expected to be around the spherical <sup>306</sup>Ubb ([[unbibium|element 122]]), but the expected low half-life and low production [[cross section (physics)|cross section]] of this nuclide makes its synthesis challenging.<ref name="Kratz" />

The most likely isotopes of ununennium to be synthesised in the near future are <sup>293</sup>Uue through <sup>296</sup>Uue, because they are populated in the 3n and 4n channels of the <sup>243</sup>Am+<sup>48</sup>Cr and <sup>249</sup>Bk+<sup>50</sup>Ti reactions.<ref name=jinr2024>{{Cite web |url=https://indico.jinr.ru/event/4343/contributions/28663/attachments/20748/36083/U%20+%20Cr%20AYSS%202024.pptx |title=Synthesis and study of the decay properties of isotopes of superheavy element Lv in Reactions <sup>238</sup>U + <sup>54</sup>Cr and <sup>242</sup>Pu + <sup>50</sup>Ti |last=Ibadullayev |first=Dastan |date=2024 |website=jinr.ru |publisher=[[Joint Institute for Nuclear Research]] |access-date=2 November 2024 |quote=}}</ref>

===Atomic and physical===
Being the first [[period 8 element]], ununennium is predicted to be an alkali metal, taking its place in the periodic table below [[lithium]], [[sodium]], [[potassium]], [[rubidium]], [[caesium]], and [[francium]]. Each of these elements has one [[valence electron]] in the outermost s-orbital (valence electron configuration ''n''s<sup>1</sup>), which is easily lost in chemical reactions to form the +1 [[oxidation state]]: thus, the alkali metals are very [[reactivity (chemistry)|reactive]] elements. Ununennium is predicted to continue the trend and have a valence electron configuration of 8s<sup>1</sup>. It is therefore expected to behave much like its lighter [[Congener (chemistry)|congener]]s; however, it is also predicted to differ from the lighter alkali metals in some properties.<ref name="Haire" />

The main reason for the predicted differences between ununennium and the other alkali metals is the [[spin–orbit interaction|spin–orbit (SO) interaction]]—the mutual interaction between the electrons' motion and [[Spin (physics)|spin]]. The SO interaction is especially strong for the superheavy elements because their electrons move faster—at speeds comparable to the [[speed of light]]—than those in lighter atoms.<ref name="Thayer" /> In ununennium atoms, it lowers the 7p and 8s electron energy levels,<!-- |level is an important word. Lv has no 8s electrons but they've been shown to affect its chemistry--> stabilizing the corresponding electrons, but two of the 7p electron energy levels are more stabilized than the other four.<ref name="Faegri">{{Cite journal | last1 = Fægri Jr. | first1 = Knut | last2 = Saue | first2 = Trond | doi = 10.1063/1.1385366 | title = Diatomic molecules between very heavy elements of group 13 and group 17: A study of relativistic effects on bonding | journal = The Journal of Chemical Physics | volume = 115 | issue = 6 | pages = 2456 | year = 2001 |bibcode = 2001JChPh.115.2456F | doi-access = free }}</ref> The effect is called subshell splitting, as it splits the 7p subshell into more-stabilized and the less-stabilized parts. Computational chemists understand the split as a change of the second ([[azimuthal quantum number|azimuthal]]) [[quantum number]] ''ℓ'' from 1 to {{frac|1|2}} and {{frac|3|2}} for the more-stabilized and less-stabilized parts of the 7p subshell, respectively.<ref name="Thayer" />{{efn|The quantum number corresponds to the letter in the electron orbital name: 0 to s, 1 to p, 2 to d, etc. See [[azimuthal quantum number]] for more information.}} Thus, the outer 8s electron of ununennium is stabilized and becomes harder to remove than expected, while the 7p<sub>3/2</sub> electrons are correspondingly destabilized, perhaps allowing them to participate in chemical reactions.<ref name="Haire" /> This stabilization of the outermost s-orbital (already significant in francium) is the key factor affecting ununennium's chemistry, and causes all the trends for atomic and molecular properties of alkali metals to reverse direction after caesium.<ref name="Pershina" />

{| align="center"
| valign=bottom | [[File:Atomic radius of alkali metals and alkaline earth metals.svg|class=skin-invert-image|thumb|none|upright=1.2|[[Empirical]] (Na–Cs, Mg–Ra) and predicted (Fr–Uhp, Ubn–Uhh) atomic radii of the alkali and alkaline earth metals from the [[period 3 element|third]] to the [[period 9 element|ninth period]], measured in [[angstrom]]s<ref name="Haire" /><ref name="pyykko" />]]
| valign=bottom | [[File:Electron affinity of alkali metals.svg|class=skin-invert-image|thumb|none|upright=1.2|Empirical (Na–Cs), semi-empirical (Fr), and predicted (Uue) electron affinities of the alkali metals from the third to the [[period 8 element|eighth period]], measured in [[electron volt]]s.<ref name="Haire" /><ref name="pyykko" /> They decrease from Li to Cs, but the Fr value, {{val|492|10|u=meV}}, is 20&nbsp;meV higher than that of Cs, and that of Uue is much higher still at 662&nbsp;meV.<ref name="Landau">{{cite journal |last1=Landau |first1=Arie |last2=Eliav |first2=Ephraim |first3=Yasuyuki |last3=Ishikawa |first4=Uzi |last4=Kador |date=25 May 2001 |title=Benchmark calculations of electron affinities of the alkali atoms sodium to eka-francium (element 119) |url=https://www.researchgate.net/publication/234859102 |journal=Journal of Chemical Physics |volume=115 |issue=6 |pages=2389–2392 |doi=10.1063/1.1386413 |access-date=15 September 2015|bibcode=2001JChPh.115.2389L }}</ref>]]
| valign=bottom | [[File:Ionization energy of alkali metals and alkaline earth metals.svg|class=skin-invert-image|thumb|none |upright=1.25|Empirical (Na–Fr, Mg–Ra) and predicted (Uue–Uhp, Ubn–Uhh) ionization energy of the alkali and alkaline earth metals from the third to the ninth period, measured in electron volts<ref name="Haire" /><ref name="pyykko">{{Cite journal|last1=Pyykkö|first1=Pekka|title=A suggested periodic table up to Z ≤ 172, based on Dirac–Fock calculations on atoms and ions|journal=Physical Chemistry Chemical Physics|volume=13 |issue=1|pages=161–168|date=2011|pmid=20967377|doi=10.1039/c0cp01575j|bibcode=2011PCCP...13..161P |s2cid=31590563 }}</ref>]]
|}

Due to the stabilization of its outer 8s electron, ununennium's first [[ionization energy]]—the energy required to remove an electron from a neutral atom—is predicted to be 4.53&nbsp;eV, higher than those of the known alkali metals from potassium onward. This effect is so large that unbiunium (element 121) is predicted to have a lower ionization energy of 4.45&nbsp;eV, so that the alkali metal in period 8 would not have the lowest ionization energy in the period, as is true for all previous periods.<ref name="Haire" /> Ununennium's [[electron affinity]] is expected to be far greater than that of caesium and francium; indeed, ununennium is expected to have an electron affinity higher than all the alkali metals lighter than it at about 0.662&nbsp;eV, close to that of [[cobalt]] (0.662&nbsp;eV) and [[chromium]] (0.676&nbsp;eV).<ref name="Landau" /> Relativistic effects also cause a very large drop in the [[polarizability]] of ununennium<ref name="Haire" /> to 169.7&nbsp;[[atomic unit|a.u.]]<ref name="Borschevsky">{{cite journal |last1=Borschevsky |first1=A. |last2=Pershina |first2=V. |last3=Eliav |first3=E. |last4=Kaldor |first4=U. |date=22 March 2013 |title=''Ab initio'' studies of atomic properties and experimental behavior of element 119 and its lighter homologs |journal=The Journal of Chemical Physics |volume=138 |issue=12 |at=124302 |doi=10.1063/1.4795433 |pmid=23556718 |bibcode=2013JChPh.138l4302B |url=http://repository.gsi.de/record/52121/files/PHN-ENNA-THEORY-08.pdf |access-date=5 December 2018 |archive-date=15 March 2022 |archive-url=https://web.archive.org/web/20220315200718/https://repository.gsi.de/record/52121/files/PHN-ENNA-THEORY-08.pdf |url-status=live }}</ref> Indeed, the static dipole polarisability (α<sub>''D''</sub>) of ununennium, a quantity for which the impacts of relativity are proportional to the square of the element's atomic number, has been calculated to be small and similar to that of sodium.<ref>{{cite journal |display-authors=3 |last1=Lim |first1=Ivan S. |last2=Pernpointner |first2=Markus |first3=Michael |last3=Seth |first4=Jon K. |last4=Laerdahl |first5=Peter |last5=Schwerdtfeger |first6=Pavel |last6=Neogrady |first7=Miroslav |last7=Urban |date=1999 |title=Relativistic coupled-cluster static dipole polarizabilities of the alkali metals from Li to element 119 |journal=Physical Review A |volume=60 |issue=4 |at=2822 |doi=10.1103/PhysRevA.60.2822 |bibcode=1999PhRvA..60.2822L}}</ref>

The electron of the [[hydrogen-like atom|hydrogen-like]] ununennium atom—oxidized so it has only one electron, Uue<sup>118+</sup>—is predicted to move so quickly that its mass is 1.99 times that of a non-moving electron, a consequence of [[Relativistic quantum chemistry|relativistic effects]]. For comparison, the figure for hydrogen-like francium is 1.29 and the figure for hydrogen-like caesium is 1.091.<ref name="Thayer" /> According to simple extrapolations of relativity laws, that indirectly indicates the contraction of the [[atomic radius]]<ref name="Thayer" /> to around 240&nbsp;[[picometer|pm]],<ref name="Haire" /> very close to that of rubidium (247&nbsp;pm); the [[metallic radius]] is also correspondingly lowered to 260&nbsp;pm.<ref name="Haire" /> The [[ionic radius]] of Uue<sup>+</sup> is expected to be 180&nbsp;pm.<ref name="Haire" />

Ununennium is predicted to have a melting point between 0&nbsp;°C and 30&nbsp;°C: thus it may be a [[liquid]] at room temperature.{{Fricke1975}} It is not known whether this continues the trend of decreasing melting points down the group, as caesium's melting point is 28.5&nbsp;°C and francium's is estimated to be around 8.0&nbsp;°C.<ref name="L&P">{{cite book |title=Analytical Chemistry of Technetium, Promethium, Astatine, and Francium |first1=Avgusta Konstantinovna |last1=Lavrukhina |first2=Aleksandr Aleksandrovich |last2=Pozdnyakov |year=1970 |publisher=Ann Arbor–Humphrey Science Publishers |others=Translated by R. Kondor |isbn=978-0-250-39923-9 |page=269}}</ref> The boiling point of ununennium is expected to be around 630&nbsp;°C, similar to that of francium, estimated to be around 620&nbsp;°C; this is lower than caesium's boiling point of 671&nbsp;°C.<ref name="Fricke1971" /><ref name="L&P" /> The density of ununennium has been variously predicted to be between 3 and 4&nbsp;g/cm<sup>3</sup>, continuing the trend of increasing density down the group: the density of francium is estimated at 2.48&nbsp;g/cm<sup>3</sup>, and that of caesium is known to be 1.93&nbsp;g/cm<sup>3</sup>.<ref name="Fricke1971" /><ref name="B&K" /><ref name="L&P" />

===Chemical===
{| class="wikitable floatright" style="font-size:85%;"
|+ Bond lengths and bond-dissociation energies of alkali metal dimers. Data for Fr{{sub|2}} and Uue{{sub|2}} are predicted.<ref name="Liddle" />
! Dimer
! Bond length<br>(Å)
! Bond-dissociation<br>energy (kJ/mol)
|-
! Li{{sub|2}}
| 2.673
| 101.9
|-
! Na{{sub|2}}
| 3.079
| 72.04
|-
! K{{sub|2}}
| 3.924
| 53.25
|-
! Rb{{sub|2}}
| 4.210
| 47.77
|-
! Cs{{sub|2}}
| 4.648
| 43.66
|-
! Fr{{sub|2}}
| ~ 4.61
| ~ 42.1
|-
! Uue{{sub|2}}
| ~ 4.27
| ~ 53.4
|}
The chemistry of ununennium is predicted to be similar to that of the alkali metals,<ref name="Haire" /> but it would probably behave more like potassium<ref name="EB">{{cite web|author=Seaborg|url=http://www.britannica.com/EBchecked/topic/603220/transuranium-element|title=transuranium element (chemical element)|website=[[Encyclopædia Britannica]]|date=c. 2006|access-date=2010-03-16|archive-date=2010-11-30|archive-url=https://web.archive.org/web/20101130112151/http://www.britannica.com/EBchecked/topic/603220/transuranium-element|url-status=live}}</ref> or rubidium<ref name="Haire" /> than caesium or francium. This is due to relativistic effects, as in their absence [[periodic trends]] would predict ununennium to be even more reactive than caesium and francium. This lowered [[reactivity (chemistry)|reactivity]] is due to the relativistic stabilization of ununennium's valence electron, increasing ununennium's first ionization energy and decreasing the [[metallic radius|metallic]] and [[ionic radius|ionic radii]];<ref name="EB" /> this effect is already seen for francium.<ref name="Haire" />

The chemistry of ununennium in the +1-oxidation state should be more similar to the chemistry of rubidium than to that of francium. On the other hand, the ionic radius of the Uue{{sup|+}} ion is predicted to be larger than that of Rb{{sup|+}}, because the 7p orbitals are destabilized and are thus larger than the p-orbitals of the lower shells. Ununennium may also show the +3 [[oxidation state]],<ref name="Haire" /> which is not seen in any other alkali metal,<ref name="Greenwood&Earnshaw">{{Greenwood&Earnshaw|p=28}}</ref> in addition to the +1 oxidation state that is characteristic of the other alkali metals and is also the main oxidation state of all the known alkali metals: this is because of the destabilization and expansion of the 7p{{sub|3/2}} spinor, causing its outermost electrons to have a lower ionization energy than what would otherwise be expected.<ref name="Haire" /><ref name="Greenwood&Earnshaw" /> The 7p{{sub|3/2}} spinor's chemical activity has been suggested to make the +5 oxidation state possible in [UueF{{sub|6}}]{{sup|−}}, analogous to [SbF{{sub|6}}]{{sup|−}} or [BrF{{sub|6}}]{{sup|−}}. The analogous francium(V) compound, [FrF{{sub|6}}]{{sup|−}}, might also be achievable, but is not experimentally known.<ref name=Cao/>

Many ununennium compounds are expected to have a large [[covalent]] character, due to the involvement of the 7p{{sub|3/2}} electrons in the bonding: this effect is also seen to a lesser extent in francium, which shows some 6p{{sub|3/2}} contribution to the bonding in francium [[superoxide]] (FrO<{{sub|2}}).<ref name="Thayer">{{cite book |last1=Thayer |first1=John S. |editor-last1=Maria |editor-first1=Barysz |editor-last2=Ishikawa |editor-first2=Yasuyuki |title=Relativistic Methods for Chemists |volume=10 |date=2010 |pages=63–67, 81, 84 |doi=10.1007/978-1-4020-9975-5_2|chapter=Relativistic Effects and the Chemistry of the Heavier Main Group Elements |publisher=Springer Netherlands |isbn=978-1-4020-9974-8 |series=Challenges and Advances in Computational Chemistry and Physics }}</ref> Thus, instead of ununennium being the most [[electropositive]] element, as a simple extrapolation would seem to indicate, caesium retains this position, with ununennium's [[electronegativity]] most likely being close to [[sodium]]'s (0.93 on the Pauling scale).<ref name="Pershina" /> The [[standard reduction potential]] of the Uue{{sup|+}}/Uue couple is predicted to be −2.9&nbsp;V, the same as that of the Fr{{sup|+}}/Fr couple and just over that of the K{{sup|+}}/K couple at −2.931&nbsp;V.{{Fricke1975|name}}

:{| class="wikitable floatright" style="font-size:85%;"
|+ Bond lengths and bond-dissociation energies of MAu (M = an alkali metal). All data are predicted, except for the bond-dissociation energies of KAu, RbAu, and [[Caesium auride|CsAu]].<ref name="Pershina" />
! Compound
! Bond length<br>(Å)
! Bond-dissociation<br>energy (kJ/mol)
|-
! KAu
| 2.856
| 2.75
|-
! RbAu
| 2.967
| 2.48
|-
! CsAu
| 3.050
| 2.53
|-
! FrAu
| 3.097
| 2.75
|-
! UueAu
| 3.074
| 2.44
|}

In the gas phase, and at very low temperatures in the condensed phase, the alkali metals form covalently bonded diatomic molecules. The metal–metal [[bond length]]s in these M{{sub|2}} molecules increase down the group from [[dilithium|Li{{sub|2}}]] to Cs{{sub|2}}, but then decrease after that to Uue{{sub|2}}, due to the aforementioned relativistic effects that stabilize the 8s orbital. The opposite trend is shown for the metal–metal [[bond-dissociation energy|bond-dissociation energies]]. The Uue–Uue bond should be slightly stronger than the K–K bond.<ref name="Pershina" /><ref name="Liddle">{{cite book |last1=Jones |first1=Cameron |last2=Mountford |first2=Philip |last3=Stasch |first3=Andreas |last4=Blake |first4=Matthew P. |editor-last=Liddle |editor-first=Stephen T. |title=Molecular Metal-Metal Bonds: Compounds, Synthesis, Properties |publisher=John Wiley and Sons |date=22 June 2015 |pages=23–24 |chapter=s-block Metal-Metal Bonds |isbn=9783527335411}}</ref> From these M{{sub|2}} dissociation energies, the [[enthalpy of sublimation]] (Δ''H''{{sub|sub}}) of ununennium is predicted to be 94&nbsp;kJ/mol (the value for francium should be around 77&nbsp;kJ/mol).<ref name="Pershina" />

The UueF molecule is expected to have a significant covalent character owing to the high electron affinity of ununennium. The bonding in UueF is predominantly between a 7p orbital on ununennium and a 2p orbital on fluorine, with lesser contributions from the 2s orbital of fluorine and the 8s, 6d<sub>''z''<sup>2</sup></sub>, and the two other 7p orbitals of ununennium. This is very different from the behaviour of s-block elements, as well as [[gold]] and [[mercury (element)|mercury]], in which the s-orbitals (sometimes mixed with d-orbitals) are the ones participating in the bonding. The Uue–F bond is relativistically expanded due to the splitting of the 7p orbital into 7p{{sub|1/2}} and 7p<{{sub|3/2}} spinors, forcing the bonding electrons into the largest orbital measured by radial extent: a similar expansion in bond length is found in the hydrides [[astatine|At]]H and TsH.<ref>{{cite journal |display-authors=3 |last1=Miranda |first1=P. S. |last2=Mendes |first2=A. P. S. |first3=J. S. |last3=Gomes |first4=C. N. |last4=Alves |first5=A. R. |last5=de Souza |first6=J. R. |last6=Sambrano |first7=R. |last7=Gargano |first8=L. G. M. |last8=de Macedo |date=2012 |title=Ab Initio Correlated All Electron Dirac-Fock Calculations for Eka-Francium Fluoride (E119F) |journal=Journal of the Brazilian Chemical Society |volume=23 |issue=6 |pages=1104–1113 |doi=10.1590/S0103-50532012000600015 |url=https://www.researchgate.net/publication/262650693 |access-date=14 January 2018 |doi-access=free}}</ref> The Uue–Au bond should be the weakest of all bonds between gold and an alkali metal, but should still be stable. This gives extrapolated medium-sized adsorption enthalpies (−Δ''H''{{sub|ads}}) of 106&nbsp;kJ/mol on gold (the francium value should be 136&nbsp;kJ/mol), 76&nbsp;kJ/mol on [[platinum]], and 63&nbsp;kJ/mol on [[silver]], the smallest of all the alkali metals, that demonstrate that it would be feasible to study the [[chromatography|chromatographic]] [[adsorption]] of ununennium onto surfaces made of [[noble metal]]s.<ref name="Pershina" /> The [[enthalpy]] of [[adsorption]] of ununennium on a [[Teflon]] surface is predicted to be 17.6&nbsp;kJ/mol, which would be the lowest among the alkali metals.<ref name="Borschevsky" /> The Δ''H''{{sub|sub}} and −Δ''H''{{sub|ads}} values for the alkali metals change in opposite directions as atomic number increases.<ref name="Pershina" />