Editing Flerovium (section)

===Chemical===
Flerovium is the heaviest known member of group 14, below lead, and is projected to be the second member of the 7p series of elements. Nihonium and flerovium are expected to form a very short subperiod corresponding to the filling of the 7p<sub>1/2</sub> orbital, coming between the filling of the 6d<sub>5/2</sub> and 7p<sub>3/2</sub> subshells. Their chemical behaviour is expected to be very distinctive: nihonium's homology to thallium has been called "doubtful" by computational chemists, while flerovium's to lead has been called only "formal".<ref name="Zaitsevskii">{{cite web|url=http://tan11.jinr.ru/pdf/07_Sep/S_3/04_Titov.pdf|title=Relativistic DFT and ab initio calculations on the seventh-row superheavy elements: E113 - E114|last1=Zaitsevskii|first1=A.|first2=C.|last2=van Wüllen|first3=A.|last3=Rusakov|first4=A.|last4=Titov|date=September 2007|website=jinr.ru|access-date=17 February 2018}}</ref>

The first five group 14 members show a +4 oxidation state and the latter members have increasingly prominent +2 chemistry due to onset of the inert pair effect. For tin, the +2 and +4 states are similar in stability, and lead(II) is the most stable of all the chemically well-understood +2 oxidation states in group 14.<ref name="Haire" /> The 7s orbitals are very highly stabilized in flerovium, so a very large sp<sup>3</sup> [[orbital hybridization]] is needed to achieve a +4 oxidation state, so flerovium is expected to be even more stable than lead in its strongly predominant +2 oxidation state and its +4 oxidation state should be highly unstable.<ref name="Haire" /> For example, the dioxide (FlO<sub>2</sub>) is expected to be highly unstable to decomposition into its constituent elements (and would not be formed by direct reaction of flerovium with oxygen),<ref name="Haire" />{{sfn|Pershina|2010|p=502}} and flerovane (FlH<sub>4</sub>), which should have Fl–H bond lengths of 1.787&nbsp;[[angstrom|Å]]<ref name="Schwerdtfeger" /> and would be the heaviest homologue of [[methane]] (the lighter compounds include [[silane]], [[germane]] and [[stannane]]), is predicted to be more thermodynamically unstable than [[plumbane]], spontaneously decomposing to flerovium(II) hydride (FlH<sub>2</sub>) and H<sub>2</sub>.{{sfn|Pershina|2010|p=503}} The tetrafluoride FlF<sub>4</sub>{{sfn|Thayer|2010|p=83}} would have bonding mostly due to ''sd'' hybridizations rather than ''sp''<sup>3</sup> hybridizations,<ref name="Fricke1971">{{cite journal|last1=Fricke|first1=B.|last2=Greiner|first2=W.|last3=Waber|first3=J. T.|date=1971|title=The continuation of the periodic table up to Z = 172. The chemistry of superheavy elements|journal=Theoretica Chimica Acta|volume=21|issue=3|pages=235–260|doi=10.1007/BF01172015|s2cid=117157377|url=https://kobra.bibliothek.uni-kassel.de/bitstream/urn:nbn:de:hebis:34-2008081923380/1/Fricke_continuation_1971.pdf|archive-date=4 March 2016|access-date=20 April 2018|archive-url=https://web.archive.org/web/20160304200000/https://kobra.bibliothek.uni-kassel.de/bitstream/urn:nbn:de:hebis:34-2008081923380/1/Fricke_continuation_1971.pdf|url-status=dead}}</ref> and its decomposition to the difluoride and fluorine gas would be exothermic.<ref name="Schwerdtfeger" /> The other tetrahalides (for example, FlCl<sub>4</sub> is destabilized by about 400&nbsp;kJ/mol) decompose similarly.<ref name="Schwerdtfeger" /> The corresponding polyfluoride anion {{chem|FlF|6|2-}} should be unstable to [[hydrolysis]] in aqueous solution, and flerovium(II) polyhalide anions such as {{chem|FlBr|3|-}} and {{chem|FlI|3|-}} are predicted to form preferentially in solutions.<ref name="Haire" /> The ''sd'' hybridizations were suggested in early calculations, as flerovium's 7s and 6d electrons share about the same energy, which would allow a volatile [[hexafluoride]] to form, but later calculations do not confirm this possibility.<ref name="Fricke1971" /> In general, spin–orbit contraction of the 7p<sub>1/2</sub> orbital should lead to smaller bond lengths and larger bond angles: this has been theoretically confirmed in FlH<sub>2</sub>.<ref name="Schwerdtfeger" /> Still, even FlH<sub>2</sub> should be relativistically destabilized by 2.6&nbsp;eV to below Fl+H<sub>2</sub>; the large spin–orbit effects also break down the usual singlet–triplet divide in the group 14 dihydrides. FlF<sub>2</sub> and FlCl<sub>2</sub> are predicted to be more stable than FlH<sub>2</sub>.<ref>{{cite journal|last1=Balasubramanian|first1=K.|date=30 July 2002|title=Breakdown of the singlet and triplet nature of electronic states of the superheavy element 114 dihydride (114H<sub>2</sub>)|journal=Journal of Chemical Physics|volume=117|issue=16|pages=7426–32|doi=10.1063/1.1508371|bibcode=2002JChPh.117.7426B}}</ref>

Due to relativistic stabilization of flerovium's 7s<sup>2</sup>7p{{su|b=1/2|p=2|w=70%}} valence electron configuration, the 0 oxidation state should also be more stable for flerovium than for lead, as the 7p<sub>1/2</sub> electrons begin to also have a mild inert pair effect:<ref name="Haire" /> this stabilization of the neutral state may bring about some similarities between the behavior of flerovium and the noble gas [[radon]].<ref name="tanm" /> Due to flerovium's expected relative inertness, diatomic compounds FlH and FlF should have lower energies of [[dissociation (chemistry)|dissociation]] than the corresponding [[lead]] compounds PbH and PbF.<ref name="Schwerdtfeger" /> Flerovium(IV) should be even more electronegative than lead(IV);{{sfn|Thayer|2010|p=83}} lead(IV) has electronegativity 2.33 on the Pauling scale, though the lead(II) value is only 1.87. Flerovium could be a [[noble metal]].<ref name="Haire" />

Flerovium(II) should be more stable than lead(II), and halides FlX<sup>+</sup>, FlX<sub>2</sub>, {{chem|FlX|3|-}}, and {{chem|FlX|4|2-}} (X = [[chlorine|Cl]], [[bromine|Br]], [[iodine|I]]) are expected to form readily. The fluorides would undergo strong hydrolysis in aqueous solution.<ref name="Haire" /> All flerovium dihalides are expected to be stable;<ref name="Haire" /> the difluoride being water-soluble.<ref name="webelements">{{cite web|last=Winter|first=M.|date=2012|title=Flerovium: The Essentials|url=http://webelements.com/flerovium/|website=WebElements|publisher=[[University of Sheffield]]|access-date=28 August 2008}}</ref> Spin–orbit effects would destabilize the dihydride (FlH<sub>2</sub>) by almost {{convert|2.6|eVpar|kJ/mol|abbr=on}}.{{sfn|Pershina|2010|p=502}} In aqueous solution, the [[oxyanion]] flerovite ({{chem|FlO|2|2-}}) would also form, analogous to [[plumbite]]. Flerovium(II) sulfate (FlSO<sub>4</sub>) and sulfide (FlS) should be very insoluble in water, and flerovium(II) [[acetate]] (Fl(C<sub>2</sub>H<sub>3</sub>O<sub>2</sub>)<sub>2</sub>) and nitrate (Fl(NO<sub>3</sub>)<sub>2</sub>) should be quite water-soluble.<ref name="Fricke1971" /> The [[standard electrode potential]] for [[redox|reduction]] of Fl<sup>2+</sup> ion to metallic flerovium is estimated to be around +0.9&nbsp;V, confirming the increased stability of flerovium in the neutral state.<ref name="Haire" /> In general, due to relativistic stabilization of the 7p<sub>1/2</sub> spinor, Fl<sup>2+</sup> is expected to have properties intermediate between those of [[mercury (element)|Hg]]<sup>2+</sup> or [[cadmium|Cd]]<sup>2+</sup> and its lighter congener Pb<sup>2+</sup>.<ref name="Haire" />