Misplaced Pages

Mercury(IV) fluoride: Difference between revisions

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
Browse history interactively
Page 1
Page 2
← Previous editContent deleted Content addedVisualWikitext
Revision as of 03:14, 5 August 2011 editMakecat (talk | contribs)Autopatrolled, Extended confirmed users, Pending changes reviewers, Rollbackers15,749 editsmNo edit summary← Previous edit Latest revision as of 16:31, 21 December 2024 edit undoAnomieBOT (talk | contribs)Bots6,566,038 editsm Dating maintenance tags: {{Cn}} {{Failed verification}} 
(65 intermediate revisions by 37 users not shown)
Line 1: Line 1:
{{chembox {{chembox
| verifiedrevid = 371584718 |verifiedrevid = 443122167
| ImageFile = Mercury-tetrafluoride-3D-balls.png |ImageFile = Mercury-tetrafluoride-3D-balls.png
| ImageFile2 = Mercury-tetrafluoride-2D.png |ImageFile2 = Mercury tetrafluoride.svg
| Section1 = {{Chembox Properties |Section1 = {{Chembox Identifiers
|SMILES=F(F)(F)F
⚫ | Formula=HgF<sub>4</sub>
|StdInChI=1S/4FH.Hg/h4*1H;/q;;;;+4/p-4
⚫ | MolarMass=276.58 g/mol}}
|StdInChIKey = JYXOXCXRRXEIOL-UHFFFAOYSA-J
}} }}
|Section2 = {{Chembox Properties
'''Mercury(IV) fluoride''', HgF<sub>4</sub>, is the first ] compound to be discovered with the metal in the ] IV. Mercury, like the other ]s (] and ]), has an s<sup>2</sup>d<sup>10</sup> ] and generally only forms bonds involving its s orbital. This means that the highest oxidation state mercury normally attains is II, and for this reason it is generally considered a ] instead of a ].
⚫ |Formula=HgF<sub>4</sub>
⚫ |MolarMass=276.58 g/mol}}
}}
'''Mercury(IV) fluoride''', HgF<sub>4</sub>, is a purported compound, the first to be reported with mercury in the +4 ]. Mercury, like the other ]s (] and ]), has an s<sup>2</sup>d<sup>10</sup> ] and generally only forms bonds involving its 6s&nbsp;orbital. This means that the highest oxidation state mercury normally attains is +2, and for this reason it is sometimes considered a ] instead of a ]. HgF<sub>4</sub> was first reported from experiments in 2007, but its existence remains disputed; experiments conducted in 2008 could not replicate the compound.<ref> {{webarchive|url=https://web.archive.org/web/20161012232329/http://www2.hull.ac.uk/science/chemistry/research/inorganicmaterials/mercurytransitionmaterial.aspx |date=2016-10-12}}</ref><ref>{{cite journal |first1=John F. |last1=Rooms |first2=Antony V. |last2=Wilson |first3=Ian |last3=Harvey |first4= Adam J. |last4=Bridgeman |first5= Nigel A. |last5=Young |title=Mercury–fluorine interactions: a matrix isolation investigation of Hg···F<sub>2</sub>, HgF<sub>2</sub> and HgF<sub>4</sub> in argon matrices. |journal=Phys. Chem. Chem. Phys. |year=2008 |volume=10 |issue=31 |pages=4594–4605 |doi=10.1039/B805608K|pmid=18665309 }}</ref>


==History== ==History==
Speculation about higher oxidation states for mercury had been around since the 1970s, and theoretical calculations in the 1990s predicted that it should be stable in the gas phase, with a ] geometry consistent with a formal d<sup>8</sup> configuration. However, experimental proof remained elusive until 2007, when HgF<sub>4</sub> was first prepared using solid ] and ] for ] at a temperature of 4 ]. The compound was detected using ].<ref>{{cite web |url=http://psichem.de/research/hg.php |title=High Oxidation States: Mercury tetrafluoride synthesized}}</ref><ref>{{cite web |url=http://www.speciation.net/Public/News/2007/10/12/3303.html |title=Elusive Hg(IV) species has been synthesized under cryogenic conditions |date=2007-10-12}}</ref> Analysis of ] and ] calculations showed that the d orbitals are involved in bonding, leading to the suggestion that mercury should be considered a transition metal after all.<ref>{{cite journal |author=Xuefang Wang |coauthors=Lester Andrews; Sebastian Riedel; and Martin Kaupp |title=Mercury Is a Transition Metal: The First Experimental Evidence for HgF<sub>4</sub>. |journal=Angew. Chem. Int. Ed. |year=2007 |volume=46 |issue=44 |pages=8371–8375 |doi=10.1002/anie.200703710 |pmid=17899620}}</ref> However, that conclusion has been challenged by W. B. Jensen with the argument that HgF<sub>4</sub> only exists under highly atypical nonequilibrium conditions and should best be considered as an exception.<ref>{{cite journal |title=Is Mercury Now a Transition Element? |author=William B. Jensen |journal=J. Chem. Educ. |year=2008 |volume=85 |pages=1182–1183 |url=http://jchemed.chem.wisc.edu/Journal/Issues/2008/Sep/abs1182.html |doi=10.1021/ed085p1182}}</ref> Speculation about higher oxidation states for mercury had existed since the 1970s, and theoretical calculations in the 1990s predicted that it should be stable in the gas phase, with a ] geometry consistent with a formal d<sup>8</sup> configuration. However, experimental proof remained elusive until 2007, when HgF<sub>4</sub> was first prepared using solid ] and ] for ] at a temperature of 4&nbsp;]. The compound was detected using ].<ref>{{cite web |url=http://psichem.de/research/hg.php |title=High Oxidation States: Mercury tetrafluoride synthesized |access-date=2008-06-26 |archive-date=2011-07-19 |archive-url=https://web.archive.org/web/20110719073458/http://psichem.de/research/hg.php |url-status=dead }}</ref><ref>{{cite web |url=http://www.speciation.net/Public/News/2007/10/12/3303.html |title=Elusive Hg(IV) species has been synthesized under cryogenic conditions |date=2007-10-12}}</ref>

However, the compound's synthesis has not been replicated in other labs, and more recent theoretical studies cast doubt on the possible existence of mercury(IV) (and copernicium(IV)) fluoride. ] computations including both relativistic effects and ] suggest that an HgF<sub>4</sub> compound would be unbound by about 2&nbsp;eV (and CnF<sub>4</sub> by 14&nbsp;eV).<ref>{{Cite book | url={{GBUrl|ZUHsCAAAQBAJ|p=348|q=348}} | title=Fundamental World of Quantum Chemistry: A Tribute to the Memory of Per-Olov Löwdin| isbn=9789401704489| editor-last1=Brändas| editor-first1=Erkki&nbsp;J.| editor-last2=Kryachko| editor-first2=Eugene S.| date=2013-03-09| publisher=Springer|volume=III|chapter=Relativistic quantum chemistry of heavy and superheavy elements|first1=Gulzari&nbsp;L.|last1=Malli|doi=10.1007/978-94-017-0448-9_16|p=348}}</ref>


==Explanation== ==Explanation==
Theoretical studies suggest that mercury is unique among the natural elements of group 12 in forming a tetrafluoride, and attribute this observation to ]. According to calculations, the tetrafluorides of the "less relativistic" elements cadmium and zinc are unstable and eliminate a fluorine molecule, F<sub>2</sub>, to form the metal-difluoride complex. On the other hand, the tetrafluoride of the "more relativistic" synthetic element 112, ], is predicted to be more stable. Theoretical studies suggest that mercury is unique among the natural elements of group&nbsp;12 in forming a ], and attribute this observation to ]. According to calculations, the tetrafluorides of the "less relativistic" elements cadmium and zinc are unstable and eliminate a fluorine molecule, F<sub>2</sub>, to form the metal difluoride complex.{{cn|date=December 2024}} On the other hand, the tetrafluoride of the "more relativistic" synthetic element&nbsp;112, ], is predicted to be more stable.<ref name="112Cn4+">{{cite book| title=The Chemistry of the Actinide and Transactinide Elements| editor1-last=Morss|editor2-first=Norman M.| editor2-last=Edelstein| editor3-last=Fuger|editor3-first=Jean| last1=Hoffman|first1=Darleane C. |last2=Lee |first2=Diana M. |last3=Pershina |first3=Valeria |chapter=Transactinides and the future elements| publisher= ]| year=2006| isbn=1-4020-3555-1| location=Dordrecht, The Netherlands| edition=3rd| ref=CITEREFHaire2006|volume=III|doi=10.1007/1-4020-3598-5_14|via=]}}</ref>{{failed verification|reason=Only says that Cn2+ would be unstable and proposes Cn4+ fait mieux; also no comparison to lighter congeners implied by "more stable"|date=December 2024}}

Subsequent ] and ] calculations indicated that bonding in HgF<sub>4</sub> (if it really exists) involves ''d''&nbsp;orbitals. This has led to the suggestion that mercury should be considered a transition metal (the group 12 metals are sometimes excluded from the transition metals because they do not oxidize beyond +2).<ref>{{cite journal |first1=Xuefang |last1=Wang |first2=Lester |last2=Andrews |first3=Sebastian |last3=Riedel |first4= Martin |last4=Kaupp |title=Mercury Is a Transition Metal: The First Experimental Evidence for HgF<sub>4</sub>. |journal=Angew. Chem. Int. Ed. |year=2007 |volume=46 |issue=44 |pages=8371–8375 |doi=10.1002/anie.200703710 |pmid=17899620}}</ref> Chemical historian ] has argued that the compound alone is insufficient to reclassify the metal, because HgF<sub>4</sub> represents at best a ].<ref>{{cite journal |title=Is Mercury Now a Transition Element? |author1-link=William B. Jensen|first=William B. |last=Jensen |journal=J. Chem. Educ. |year=2008 |volume=85 |pages=1182–1183 |doi=10.1021/ed085p1182 |issue=9|bibcode=2008JChEd..85.1182J |doi-access=free}}</ref>

==Synthesis and properties==
HgF<sub>4</sub> is produced by the reaction of elemental mercury with ]:

:Hg + 2 F<sub>2</sub> → HgF<sub>4</sub>

HgF<sub>4</sub> is only stable in matrix isolation at {{cvt|4|K|°C|0}}; upon heating, or if the HgF<sub>4</sub> molecules touch each other, it decomposes to ] and fluorine:

:HgF<sub>4</sub> → HgF<sub>2</sub> + F<sub>2</sub>

HgF<sub>4</sub> is a ], square planar molecule. The mercury atom has a formal 6s<sup>2</sup>5d<sup>8</sup>6p<sup>6</sup> electron configuration, and as such obeys the ] but not the ]. HgF<sub>4</sub> is ] with the ] anion, {{chem|AuF|4|-}}, and is valence isoelectronic with the ] ({{chem|AuCl|4|-}}), ] ({{chem|AuBr|4|-}}), and ] ({{chem|PtCl|4|2-}}) anions.


==References== ==References==
Line 19: Line 39:


{{Mercury compounds}} {{Mercury compounds}}
{{Fluorides}}


] ]
] ]
]

]
]
]
]