Thionyl tetrafluoride

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| ImageFile = Sulfur oxytetrafluoride.png

| ImageName = Structure of thionyl tetrafluoride

| ImageFileL1 = Thionyl-tetrafluoride-3D-balls.png

| ImageNameL1 = Ball-and-stick model of thionyl tetrafluoride

| ImageFileR1 = Thionyl-tetrafluoride-3D-SF.png

| ImageNameR1 = Space-filling model of thionyl tetrafluoride

| IUPACName = Thionyl tetrafluoride

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|Section1={{Chembox Identifiers

| Abbreviations =

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| CASNo = 13709-54-1

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| PubChem = 139557

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| ChemSpiderID = 123077

| SMILES = O=S(F)(F)(F)F

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/F4OS/c1-6(2,3,4)5

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = DUGWRBKBGKTKOX-UHFFFAOYSA-N

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|Section2={{Chembox Properties

| Formula = {{chem2|SOF4}}

| S=1|O=1|F=4

| Appearance = colorless gas

| Density = 1.653−0.0036T (°C) liquid

| MeltingPtC = −99.6

| MeltingPt_notes =

| BoilingPtC = −49

| BoilingPt_notes = 5090 cal/mol heat of vapourisation

| Solubility = reaction in water

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| Solvent = ether, benzene

| LogP = 7.2349−859.58/T−26275/T²

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|Section3={{Chembox Structure

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| MolShape = distorted trigonal bipyramid}}

|Section7={{Chembox Hazards

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| GHSPictograms = {{GHS05}}{{GHS06}}

| GHSSignalWord = Danger

| HPhrases = {{H-phrases|300|310|314|330}}

| PPhrases = {{P-phrases|260|262|264|270|271|280|284|301+310|301+330+331|302+350|303+361+353|304+340|305+351+338|310|320|321|322|330|361|363|403+233|405|501}}

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|Section8={{Chembox Related

| OtherAnions =

| OtherCations =

| OtherFunction = {{ubl|Thionyl fluoride|Selenyl tetrafluoride}}

| OtherFunction_label = oxohalides

| OtherCompounds = {{ubl|Phosphoryl trifluoride|Pentafluorosulfur hypofluorite|Sulfuryl fluoride|Sulfur hexafluoride|Thiazyl trifluoride|Chromium oxytetrafluoride}}}}

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Thionyl tetrafluoride, also known as sulfur tetrafluoride oxide, is an inorganic compound with the formula {{chem2|SOF4|auto=1}}. It is a colorless gas.

The shape of the molecule is a distorted trigonal bipyramid, with the oxygen found on the equator. The atoms on the equator have shorter bond lengths than the fluorine atoms on the axis. In the gas-phase, the sulfur-oxygen bond is 1.409 Å. The S−F bond on the axis has length 1.596 Å and the S−F bond on the equator has length 1.539 Å. The angle between the equatorial fluorine atoms is 112.8°. The angle between axial fluorine and oxygen is 97.7°. The angle between oxygen and equatorial fluorine is 123.6° and between axial and equatorial fluorine is 85.7°.{{cite journal |last1=Hedberg |first1=Lise |last2=Hedberg |first2=Kenneth |title=Thionyl tetrafluoride. Reanalysis of the molecular structure and resolution of the multiple model problem |journal=The Journal of Physical Chemistry |date=March 1982 |volume=86 |issue=5 |pages=598–602 |doi=10.1021/j100394a004}} Slight variations of bonds lengths and angles has been observed in solid-state by X-ray analysis.{{cite journal |last1=Sturm |first1=Johanna |last2=Millanvois |first2=Alexandre |last3=Bahri |first3=Carlota|last4=Golz |first4=Paul|last5=Limberg |first5=Niklas|last6=Wiesner |first6=Anja|last7=Riedel |first7= Sebastian |title=Streamlining Thionyl Tetrafluoride (SOF4) and Pentafluoro-Oxosulfate [OSF5]− Anions Syntheses |journal=Chemistry: A European Journal |date=March 2024 |volume=30 |issue=71 |pages=e202403365|doi=10.1002/chem.202403365|pmid=39352264}} The fluorine atoms only produce one NMR line, probably because they exchange positions. It is isoelectronic with phosphorus pentafluoride.

Formation

Thionyl fluoride reacting with fluorine gas can produce thionyl tetrafluoride.Harry Julius Emeléus and A.G. Sharpe Advances in Inorganic Chemistry Volume 2 Academic Press 1960 page 117 [https://books.google.com/books?id=KxuDjYsMLxMC] This was how the gas was first discovered by Moissan and Lebeau in 1902. They identified the formula by the pressure changes resulting from the reaction. Silver fluoride and platinum are capable of catalyzing the reaction.

It can also be formed the reaction of silver difluoride with thionyl fluoride at {{convert|200|C|F|order=flip}},{{cite journal|doi=10.1021/ja01589a013 | volume=78 | issue=8 | title=Pentafluorosulfur Hypofluorite and Thionyl Tetrafluoride | journal=Journal of the American Chemical Society | pages=1553–1557 | last1 = Dudley | first1 = F. B.| year=1956 | bibcode=1956JAChS..78.1553D}} or by electrolyzing hydrogen fluoride with a solution of sulfur dioxide, which also made oxygen difluoride and sulfuryl fluoride. Thionyl chloride or thionyl fluoride electrolyzed with hydrogen fluoride produced even more of the gas.{{cite journal |last1=Nagase |first1=Shunji |last2=Abe |first2=Takashi |last3=Baba |first3=Hajime |title=Fluorination of Inorganic Sulfur Compounds |journal=Bulletin of the Chemical Society of Japan |date=1 July 1969 |volume=42 |issue=7 |pages=2062–2064 |doi=10.1246/bcsj.42.2062}}

Reactions

Thionyl tetrafluoride reacts with water to make hydrofluoric acid, sulfurofluoridic acid, and sulfuryl difluoride. Mercury can strip off fluoride to make thionyl fluoride and mercurous fluoride. Strong bases result in formation of fluoride and fluorosulfate ions.

Reactions with the strong Lewis acids, such as AsF5 and SbF5, result in the formation of trifluorosulfoxonium cation {{chem2|[SOF3]+}} and the corresponding salts {{chem2|[SOF3]+[AsF6]-}} (trifluorosulfoxonium hexafluoroarsenate(V)) and {{chem2|[SOF3]+[SbF6]-}} (trifluorosulfoxonium hexafluoroantimonate(V)), respectively.{{Cite journal |last1=Brownstein |first1=M. |last2=Dean |first2=P. A. W. |last3=Gillespie |first3=R. J. |date=1970-01-01 |title=The trifluorosulphur(VI) oxide cation, SOF3+ |url=https://pubs.rsc.org/en/content/articlelanding/1970/c2/c29700000009 |journal=Journal of the Chemical Society D: Chemical Communications |language=en |issue=1 |pages=9 |doi=10.1039/C29700000009 |issn=0577-6171|url-access=subscription }}

= Click chemistry =

Thionyl tetrafluoride can be used in click chemistry through reactions with primary amines known as sulfur(VI) fluoride exchange (SuFEx).{{Cite journal|last1=Li|first1=Suhua|last2=Wu|first2=Peng|last3=Moses|first3=John E.|last4=Sharpless|first4=K. Barry|date=2017-02-01|title=Multidimensional SuFEx Click Chemistry: Sequential Sulfur(VI) Fluoride Exchange Connections of Diverse Modules Launched From An SOF4 Hub|journal=Angewandte Chemie International Edition|language=en|pages=2903–2908|doi=10.1002/anie.201611048|pmid=28165188|pmc=5434761|issn=1521-3773|volume=56|issue=11}} This kind of reaction was the first "click" reaction to generate a three-dimensional core.

References