Editing Ununennium (section)

===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" />