Wikipedia:WikiProject Chemicals/Chembox validation/VerifiedDataSandbox and Thionyl chloride: Difference between pages

{{Short description|Inorganic compound (SOCl2)}}

|Verifiedfields = changed

|Watchedfields = changed

|verifiedrevid = 470607362

|Name = Thionyl chloride

|ImageFile = Thionyl-chloride-2D-dimensions.png

|ImageSize = 150px

|ImageFile1 = Thionyl-chloride-from-xtal-3D-balls-B.png

|ImageSize1 = 140px

|ImageName1 = Ball-and-stick model of thionyl chloride

|ImageFile2 = Freshly distilled thionyl chloride in a bomb.jpg

|IUPACName = Thionyl chloride

|OtherNames = {{Plainlist|

* Thionyl dichloride

* Sulfurous oxychloride

* Sulfinyl chloride

* Sulfinyl dichloride

* Dichlorosulfoxide

* Sulfur oxide dichloride

* Sulfur monoxide dichloride

* Sulfuryl(IV) chloride

|Section1 = {{Chembox Identifiers

|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

|ChemSpiderID = 22797

|InChI = 1/Cl2OS/c1-4(2)3

|InChIKey = FYSNRJHAOHDILO-UHFFFAOYAN

|ChEBI_Ref = {{ebicite|correct|EBI}}

|ChEBI = 29290

|SMILES = ClS(Cl)=O

|StdInChI_Ref = {{stdinchicite|correct|chemspider}}

|StdInChI = 1S/Cl2OS/c1-4(2)3

|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

|StdInChIKey = FYSNRJHAOHDILO-UHFFFAOYSA-N

|CASNo = 7719-09-7

|CASNo_Ref = {{cascite|correct|CAS}}

|UNII_Ref = {{fdacite|changed|FDA}}

|UNII = 4A8YJA13N4

|EINECS = 231-748-8

|PubChem = 24386

|RTECS = XM5150000

|UNNumber = 1836

}}

|Section2 = {{Chembox Properties

|Formula = {{chem2|SOCl2}}

|MolarMass = 118.97{{nbsp}}g/mol

|Appearance = Colourless liquid (yellows on ageing)

|Odour = Pungent and unpleasant

|Density = 1.638{{nbsp}}g/cm³, liquid

|Solubility = Reacts

|SolubleOther = Soluble in most aprotic solvents: [[toluene]], [[chloroform]], [[diethyl ether]]. Reacts with protic solvents such as alcohols

|MeltingPtC = −104.5

|BoilingPtC = 74.6

|Viscosity = 0.6 [[Poise (unit)|cP]]

|RefractIndex = 1.517 (20{{nbsp}}°C)<ref>{{cite book|last1=Patnaik|first1=Pradyot|title=Handbook of Inorganic Chemicals|url=https://archive.org/details/Handbook_of_Inorganic_Chemistry_Patnaik|date=2003|publisher=McGraw-Hill|location=New York, NY|isbn=0-07-049439-8}}</ref>

|VaporPressure = {{Plainlist|

* 384&nbsp;Pa (−40&nbsp;°C)

* 4.7&nbsp;kPa (0&nbsp;°C)

* 15.7&nbsp;kPa (25&nbsp;°C)<ref>{{nist|name=Thionyl chloride|id=C7719097|accessdate=2014-05-11|mask=1F|units=SI}}</ref>

}}

}}

|Section3 = {{Chembox Structure

|MolShape = pyramidal

|Dipole = 1.44&nbsp;[[Debye|D]]

}}

|Section4 = {{Chembox Thermochemistry

|DeltaHf = −245.6{{nbsp}}kJ/mol (liquid)<ref name=CRC>{{cite book|editor1-last=Lide|editor1-first=David R.|display-editors=etal|title=CRC Handbook of Chemistry and Physics|date=1996|publisher=CRC Press|location=Boca Raton, FL|isbn=0-8493-0476-8|pages=5–10|edition=76th}}</ref>

|Entropy = 309.8{{nbsp}}kJ/mol (gas)<ref name=CRC />

|HeatCapacity = 121.0{{nbsp}}J/mol (liquid)<ref name=CRC />

}}

|Section5 = {{Chembox Hazards

|GHSPictograms = {{GHS05}}{{GHS07}}{{GHS06}}

|GHSSignalWord = Danger

|HPhrases = {{H-phrases|302|314|331}}

|PPhrases = {{P-phrases|261|280|305+351+338|310}}

|MainHazards = Very toxic, corrosive, releases [[hydrochloric acid|HCl]] on contact with water

|NFPA-H = 4

|NFPA-F = 0

|NFPA-R = 2

|NFPA-S = W

|FlashPt = Non-flammable

|IDLH = N.D.<ref name=PGCH>{{PGCH|0611}}</ref>

|REL = C 1{{nbsp}}ppm (5{{nbsp}}mg/m³)<ref name=PGCH/>

|PEL = None<ref name=PGCH/>

}}

|Section6 = {{Chembox Related

|OtherFunction = {{Plainlist|

* [[Thionyl fluoride]]

* [[Thionyl bromide]]

* [[Thionyl iodide]]

}}

|OtherFunction_label = Thionyl halides

|OtherCompounds = {{Plainlist|

* [[Sulfuryl chloride]]

* [[Selenium oxydichloride]]

}}

}}

}}

'''Thionyl chloride''' is an [[inorganic compound]] with the [[chemical formula]] {{chem2|SOCl2}}. It is a moderately [[Volatility (chemistry)|volatile]], colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a [[Halogenation|chlorinating]] reagent, with approximately {{convert|45,000|t|ST}} per year being produced during the early 1990s,<ref>{{Ullmann|first1=H.-D.|last1=Lauss|first2=W.|last2=Steffens|title=Sulfur Halides|doi=10.1002/14356007.a25_623}}</ref> but is occasionally also used as a solvent.<ref>{{cite journal |last1=Oka |first1=Kitaro |title=Some Applications of Thionyl Chloride in Synthetic Organic Chemistry |journal=Synthesis |date=1981 |volume=1981 |issue=9 |pages=661–681 |doi=10.1055/s-1981-29563|s2cid=94917739 }}</ref><ref>{{cite journal |last1=Calderazzo |first1=Fausto |last2=Dell'Amico |first2=Daniela Belli |title=Syntheses of carbonyl halides of late transition elements in thionyl chloride as solvent. Carbonyl complexes of palladium(II) |journal=Inorganic Chemistry |date=April 1981 |volume=20 |issue=4 |pages=1310–1312 |doi=10.1021/ic50218a072}}</ref><ref>{{cite journal |last1=Garber |first1=E. B. |last2=Pease |first2=L. E. D. |last3=Luder |first3=W. F. |title=Titration of Aprotic Acids in Thionyl Chloride |journal=Analytical Chemistry |date=20 April 1953 |volume=25 |issue=4 |pages=581–583 |doi=10.1021/ac60076a012}}</ref> It is toxic, reacts with water, and is also [[List of Schedule 3 substances (CWC)|listed]] under the [[Chemical Weapons Convention]] as it may be used for the production of [[chemical weapons]].

Thionyl chloride is sometimes confused with [[sulfuryl chloride]], {{chem2|SO2Cl2}}, but the properties of these compounds differ significantly. Sulfuryl chloride is a source of [[chlorine]] whereas thionyl chloride is a source of [[chloride]] ions.

==Production==

The major industrial synthesis involves the reaction of [[sulfur trioxide]] and [[sulfur dichloride]]:<ref name=Greenwood>{{Greenwood&Earnshaw2nd|page=694}}</ref> This synthesis can be adapted to the laboratory by heating oleum to slowly distill the sulfur trioxide into a cooled flask of sulfur dichloride.<ref>{{cite web|last=Brauer|first=George|date=1963|title=Handbook of Preparative Inorganic Chemistry|doi=10.1016/B978-0-12-395590-6.50015-6|pages=382–383}}</ref>

:<chem>SO3 + SCl2 -> SOCl2 + SO2</chem>

Other methods include syntheses from:

*[[Phosphorus pentachloride]]:

*:<chem>SO2 + PCl5 -> SOCl2 + POCl3</chem>

*[[Chlorine]] and [[sulfur dichloride]]:

*:<chem>SO2 + Cl2 + SCl2 -> 2 SOCl2</chem>

*:<chem>SO3 + Cl2 + 2SCl2 -> 3 SOCl2</chem>

*[[Phosgene]]:

*:<chem>SO2 + COCl2 -> SOCl2 + CO2</chem>

The second of the above five reactions also affords [[phosphoryl chloride|phosphorus oxychloride]] (phosphoryl chloride), which resembles thionyl chloride in many of its reactions. They may be separated by distillation, since thionyl chloride boils at a much lower temperature than phosphoryl chloride{{cn|date=May 2024}}.

==Properties and structure==

{| style="float: right;"

|[[File:Thionyl-chloride-xtal-3D-vdW-B.png|thumbnail|left|120px|Crystal structure of solid SOCl₂]]

|}

SOCl₂ adopts a [[trigonal pyramidal molecular geometry]] with C_s [[molecular symmetry]]. This geometry is attributed to the effects of the [[lone pair]] on the central sulfur(IV) center.

In the solid state SOCl₂ forms [[monoclinic]] crystals with the [[space group]] P2₁/c.<ref>{{cite journal|last1=Mootz|first1=D.|last2=Merschenz-Quack|first2=A.|title=Structures of thionyl halides: SOCl₂ and SOBr₂|journal=Acta Crystallographica Section C|date=15 May 1988|volume=44|issue=5|pages=926–927|doi=10.1107/S010827018800085X|bibcode=1988AcCrC..44..926M |url=http://journals.iucr.org/c/issues/1988/05/00/bx0227/bx0227.pdf}}</ref>

===Stability===

Thionyl chloride has a long shelf life, however "aged" samples develop a yellow hue, possibly due to the formation of [[disulfur dichloride]]. It slowly [[thermal decomposition|decomposes]] to [[Disulfur dichloride|S₂Cl₂]], [[sulphur dioxide|SO₂]] and [[chlorine|Cl₂]] at just above the boiling point.<ref name=Greenwood /><ref>{{cite book|editor-first=Georg|editor-last=Brauer|translator1=Scripta Technica|translator2-last=Reed|translator2-first=F.|title=Handbook of Preparative Inorganic Chemistry|volume=1|date=1963|publisher=Academic Press|location=New York, NY|isbn=978-0121266011|page=383|edition=2nd}}</ref> Thionyl chloride is susceptible to [[photodissociation|photolysis]], which primarily proceeds via a radical mechanism.<ref>{{cite journal|last1=Donovan|first1=R. J.|last2=Husain|first2=D.|last3=Jackson|first3=P. T.|title=Spectroscopic and kinetic studies of the SO radical and the photolysis of thionyl chloride|journal=Transactions of the Faraday Society|volume=65|pages=2930|doi=10.1039/TF9696502930|year=1969}}</ref> Samples showing signs of ageing can be purified by distillation under reduced pressure, to give a colourless liquid.<ref>{{cite journal|last1=Friedman|first1=L.|last2=Wetter|first2=W. P.|title=Purification of thionyl chloride|journal=Journal of the Chemical Society A: Inorganic, Physical, Theoretical|date=1967|pages=36|doi=10.1039/J19670000036}}</ref>

[[File:Thionyl chloride 25ml.jpg|thumb|Impure thionyl chloride, appearing slightly yellow]]

==Reactions==

Thionyl chloride is mainly used in the industrial production of [[organochlorine compound]]s, which are often intermediates in pharmaceuticals and agrichemicals. It usually is preferred over other reagents, such as [[phosphorus pentachloride]], as its by-products (HCl and {{chem2|SO2}}) are gaseous, which simplifies purification of the product.

Many of the products of thionyl chloride are themselves highly reactive and as such it is involved in a wide range of reactions.

===With water and alcohols===

Thionyl chloride reacts exothermically with water to form [[sulfur dioxide]] and [[hydrochloric acid]]:

:<chem>SOCl2 + H2O -> 2 HCl + SO2</chem>

By a similar process it also reacts with [[Alcohol (chemistry)|alcohol]]s to form [[haloalkane|alkyl chlorides]]. If the alcohol is [[chiral]] the reaction generally proceeds via an [[SNi|S_Ni]] mechanism with retention of stereochemistry;<ref>{{March6th|page=469}}</ref> however, depending on the exact conditions employed, stereo-inversion can also be achieved. Historically the use of {{chem2|SOCl2}} with [[pyridine]] was called the [[Darzens halogenation]], but this name is rarely used by modern chemists.

[[File:SNi reaction mechanism.svg|framed|center|Conversion of a secondary alcohol to a chloroalkane by thionyl chloride.]]

Reactions with an excess of alcohol produce [[sulfite ester]]s, which can be powerful [[methylation]], [[alkylation]] and hydroxyalkylation reagents.<ref>{{cite journal|last1=Van Woerden|first1=H. F.|title=Organic Sulfites|journal=Chemical Reviews|volume=63|issue=6|pages=557–571|doi=10.1021/cr60226a001|year=1963}}</ref>

:<chem>SOCl2 + 2 R-OH -> (R-O)2SO + 2 HCl</chem>

For example, the addition of {{chem2|SOCl2}} to [[amino acid]]s in methanol selectively yields the corresponding methyl esters.<ref>{{cite journal|last1=Brenner|first1=M.|last2=Huber|first2=W.|title=Herstellung von α-Aminosäureestern durch Alkoholyse der Methylester|trans-title=Manufacture of α-amino acid esters by alcoholysis of methyl esters|journal=Helvetica Chimica Acta|volume=36|issue=5|pages=1109–1115|doi=10.1002/hlca.19530360522|language=de|year=1953}}</ref>

===With carboxylic acids===

Classically, it converts [[carboxylic acid]]s to [[acyl chloride]]s:<ref>{{Clayden|page=295}}</ref><ref>{{OrgSynth | last1 = Allen | first1 = C. F. H. | last2 = Byers | first2 = J. R. Jr | last3 = Humphlett | first3 = W. J. | collvol = 4 | collvolpages = 739 | year = 1963 | title = Oleoyl chloride | prep = cv4p0739}}</ref><ref>{{OrgSynth | last1 = Rutenberg | first1 = M. W. | last2 = Horning | first2 = E. C. | collvol = 4 | collvolpages = 620 | year = 1963 | title = 1-Methyl-3-ethyloxindole | prep = cv4p0620}}</ref>

: <chem>SOCl2 + R-COOH -> R-COCl + SO2 + HCl</chem>

The reaction mechanism has been investigated:<ref>{{Clayden|page=}}</ref>

:[[File:Action of thionyl chloride on carboxylic acid.png|450px]]

===With nitrogen species===

With primary amines, thionyl chloride gives [[sulfinylamine]] derivatives (RNSO), one example being ''N''-[[sulfinylaniline]]. Thionyl chloride reacts with primary [[formamide]]s to form [[isocyanide]]s<ref>{{OrgSynth | last1 = Niznik | first1 = G. E. | last2 = Morrison | first2 = W. H., III | last3 = Walborsky | first3 = H. M. | collvol = 6 | collvolpages = 751 | year = 1988 | title = 1-''d''-Aldehydes from organometallic reagents: 2-methylbutanal-1-''d'' | prep = cv6p0751}}</ref> and with secondary formamides to give chloro[[iminium]] ions; as such a reaction with [[dimethylformamide]] will form the [[Vilsmeier–Haack reaction|Vilsmeier reagent]].<ref>{{cite journal|last1=Arrieta|first1=A.|last2=Aizpurua|first2=J. M.|last3=Palomo|first3=C.|title=''N'',''N''-Dimethylchlorosulfitemethaniminium chloride (SOCl2-DMF) a versatile dehydrating reagent|journal=Tetrahedron Letters|volume=25|issue=31|pages=3365–3368|doi=10.1016/S0040-4039(01)81386-1|year=1984}}</ref>

By an analogous process primary [[amide]]s will react with thionyl chloride to form [[imidoyl chloride]]s, with secondary amides also giving chloro[[iminium]] ions. These species are highly reactive and can be used to catalyse the conversion of carboxylic acids to acyl chlorides,<ref name = clayden>{{cite book | author = Clayden, J. | title = Organic Chemistry | publisher = Oxford University Press | location = Oxford | year = 2001 | pages = [https://archive.org/details/organicchemistry00clay_0/page/276 276–296] | isbn = 0-19-850346-6 | url-access = registration | url = https://archive.org/details/organicchemistry00clay_0/page/276 }}</ref> they are also exploited in the [[Bischler–Napieralski reaction]] as a means of forming [[isoquinoline]]s.

[[File:Acyl chloride via amide catalysis.png|650px|center]]

Primary amides will continue on to form [[nitrile]]s if heated ([[Von Braun amide degradation]]).<ref>{{OrgSynth | last1 = Krynitsky | first1 = J. A. | last2 = Carhart | first2 = H. W. | collvol = 4 | collvolpages = 436 | year = 1963 | title = 2-Ethylhexanonitrile | prep = cv4p0436}}</ref>

Thionyl chloride has also been used to promote the [[Beckmann rearrangement]] of [[oxime]]s.

===With sulfur species===

* Thionyl chloride will transform [[sulfinic acid]]s into [[sulfinyl chloride]]s<ref>{{OrgSynth | last1 = Hulce | first1 = M. | last2 = Mallomo | first2 = J. P. | last3 = Frye | first3 = L. L. | last4 = Kogan | first4 = T. P. | last5 = Posner | first5 = G. H. | collvol = 7 | collvolpages = 495 | year = 1990 | title = (''S'')-(+)-2-(''p''-toluenesulfinyl)-2-cyclopentenone: Precursor for enantioselective synthesis of 3-substituted cyclopentanones | prep = cv7p0495}}</ref><ref>{{OrgSynth | last = Kurzer | first= F. | collvol = 4 | collvolpages = 937 | year = 1963 | title = ''p''-Toluenesulfinyl chloride | prep = cv4p0937}}</ref>

* [[Sulfonic acid]]s react with thionyl chloride to produce [[sulfonyl chloride]]s.<ref>{{OrgSynth | last1 = Weinreb | first1 = S. M. | last2 = Chase | first2 = C. E. | last3 = Wipf | first3 = P. | last4 = Venkatraman | first4 = S. | collvol = 10 | collvolpages = 707 | year = 2004 | title = 2-Trimethylsilylethanesulfonyl chloride (SES-Cl) | prep = v75p0161}}</ref><ref>{{OrgSynth | last1 = Hazen | first1 = G. G. | last2 = Bollinger | first2 = F. W. | last3 = Roberts | first3 = F. E. | last4 = Russ | first4 = W. K. | last5 = Seman | first5 = J. J. | last6 = Staskiewicz | first6 = S. | collvol = 9 | collvolpages = 400 | year = 1998 | title = 4-Dodecylbenzenesulfonyl azides | prep = cv9p0400}}</ref> Sulfonyl chlorides have also been prepared from the direct reaction of the corresponding [[diazonium]] salt with thionyl chloride.<ref>{{cite journal | title = Aqueous Process Chemistry: The Preparation of Aryl Sulfonyl Chlorides |first1=P. J. |last1=Hogan |first2=B. G. |last2=Cox | journal = Organic Process Research & Development | year = 2009 | volume = 13 | issue = 5 | pages = 875–879 | doi = 10.1021/op9000862}}</ref>

* Thionyl chloride can be used in variations of the [[Pummerer rearrangement]].

[[File:Pummerer Ex ThionylChloride.png|400px|center]]

===With phosphorus species===

Thionyl chloride converts [[phosphonic acid]]s and [[phosphonate]]s into [[phosphoryl chloride]]s. It is for this type of reaction that thionyl chloride is listed as a [[List of Schedule 3 substances (CWC)|Schedule 3]] compound, as it can be used in the "di-di" method of producing G-series [[nerve agent]]s. For example, thionyl chloride converts [[dimethyl methylphosphonate]] into [[methylphosphonic acid dichloride]], which can be used in the production of [[sarin]] and [[soman]].

===With metals===

As {{chem2|SOCl2}} reacts with water it can be used to dehydrate various metal chloride hydrates, such [[magnesium chloride]] ({{chem2|MgCl2*6H2O}}), [[aluminium chloride]] ({{chem2|AlCl3*6H2O}}), and [[iron(III) chloride]] ({{chem2|FeCl3*6H2O}}).<ref name=Greenwood /> This conversion involves treatment with refluxing thionyl chloride and follows the following general equation:<ref>{{cite book | first1 = A. R. | last1 =Pray | first2 = R. F. | last2 = Heitmiller | first3 = S. | first4 = V. D. | last4 = Aftandilian | first5 = T. | last5 = Muniyappan | first6 = D. | last6 = Choudhury | first7 = M. | last7 = Tamres | last3 = Strycker | title = Inorganic Syntheses | chapter = Anhydrous Metal Chlorides | volume = 28 | pages = 321–323 | doi = 10.1002/9780470132593.ch80 | year = 1990 | isbn = 978-0-470-13259-3 }}</ref>

:<chem>MCl_\mathit{n}\! .\! \mathit{x}\ H2O{} + \mathit{x}\ SOCl2 -> MCl_\mathit{n}{} + \mathit{x}\ SO2{} + 2\! \mathit{x}\ HCl</chem>

===Other reactions===

* Thionyl chloride can engage in a range of different electrophilic addition reactions. It adds to alkenes in the presence of {{chem2|AlCl3}} to form an aluminium complex which can be hydrolysed to form a [[sulfinic acid]]. Both aryl sulfinyl chlorides and diaryl sulfoxides can be prepared from arenes through reaction with thionyl chloride in [[triflic acid]]<ref>{{March6th|page=697}}</ref> or the presence of catalysts such as {{chem2|BiCl3}}, {{chem2|Bi(OTf)3}}, {{chem2|LiClO4}} or {{chem2|NaClO4}}.<ref>{{cite journal|last1=Peyronneau|first1=M.|last2=Roques|first2=N.|last3=Mazières|first3=S.|last4=Le Roux|first4=C.|title=Catalytic Lewis Acid Activation of Thionyl Chloride: Application to the Synthesis of Aryl Sulfinyl Chlorides Catalyzed by Bismuth(III) Salts|journal=Synlett|date=2003|issue=5|pages=0631–0634|doi=10.1055/s-2003-38358}}</ref><ref>{{cite journal |last1=Bandgar |first1= B. P. |last2=Makone|first2= S. S. | title = Lithium/Sodium Perchlorate Catalyzed Synthesis of Symmetrical Diaryl Sulfoxides| year = 2004 | journal = Synthetic Communications | volume = 34| pages = 743–750 | doi = 10.1081/SCC-120027723 | issue = 4 |s2cid= 96348273}}</ref>

* In the laboratory, a reaction between thionyl chloride and an excess of [[anhydrous]] alcohol can be used to produce anhydrous alcoholic solutions of [[HCl]].

* Thionyl chloride undergoes halogen exchange reactions to give other thionyl species.

:Reactions with fluorinating agents such as [[antimony trifluoride]] give [[thionyl fluoride]]:

::<chem>3 SOCl2 + 2 SbF3 -> 3 SOF2 + 2 SbCl3</chem>

: A reaction with [[hydrogen bromide]] gives [[thionyl bromide]]:

:: <chem>SOCl2 + 2 HBr -> SOBr2 + 2 HCl</chem>

:Thionyl iodide can likewise be prepared by a reaction with potassium iodide, but is reported to be highly unstable.<ref>{{cite journal |last1=Rao |first1=M. R. Aswathanarayana |title=Thionyl iodide: Part I. Formation of thionyl iodide |journal=Proceedings of the Indian Academy of Sciences - Section A |date=March 1940 |volume=11 |issue=3 |pages=185–200 |doi=10.1007/BF03046547|s2cid=104552644 }}</ref><ref>{{cite journal |last1=Rao |first1=M. R. Aswathanarayana |title=Thionyl iodide: Part II. Rate of decomposition and spectroscopic |journal=Proceedings of the Indian Academy of Sciences - Section A |date=March 1940 |volume=11 |issue=3 |pages=201–205 |doi=10.1007/BF03046548|s2cid=104752226 }}</ref>

==Batteries==

[[File:Lithium Thionyl Chloride Battery.JPG|200px|thumb|right|A selection of lithium–thionyl chloride batteries]]

Thionyl chloride is a component of lithium–thionyl chloride [[lithium battery|batteries]],<ref>{{cite journal |last1=Gangadharan |first1=R. |last2=Namboodiri |first2=P.N.N. |last3=Prasad |first3=K.V. |last4=Viswanathan |first4=R. |title=The lithium—thionyl chloride battery — a review |journal=Journal of Power Sources |date=January 1979 |volume=4 |issue=1 |pages=1–9 |doi=10.1016/0378-7753(79)80032-4|bibcode=1979JPS.....4....1G }}</ref> where it acts as the positive electrode (in batteries: [[cathode]]) with [[lithium]] forming the negative electrode ([[anode]]); the [[electrolyte]] is typically [[lithium tetrachloroaluminate]]. The overall discharge reaction is as follows:

:<chem>4 Li + 2 SOCl2 -> 4 LiCl + 1/8 S8 + SO2</chem>

These non-rechargeable batteries had many advantages over other forms of lithium batteries such as a high energy density, a wide operational temperature range, and long storage and operational lifespans. However, their high cost, non-rechargeability, and safety concerns have limited their use. The contents of the batteries are highly toxic and require special disposal procedures; additionally, they may explode if shorted. The technology was used on the [[Sojourner (rover)|Sojourner]] Mars rover.

==Safety==

SOCl₂ is highly reactive and can violently release hydrochloric acid upon contact with water and alcohols. It is also a controlled substance under the [[Chemical Weapons Convention]], where it is listed as a [[List of Schedule 3 substances (CWC)|Schedule 3]] substance, since it is used in the manufacture of G-series [[nerve agent]]s{{citation needed|date=August 2018}} and the Meyer and Meyer&ndash;Clarke methods of producing [[mustard gas|sulfur-based mustard gases]].<ref>{{cite book|url=http://books.nap.edu/openbook.php?record_id=2058&page=71|title=Chapter 5: Chemistry of Sulfur Mustard and Lewisite|author=Institute of Medicine |year=1993 |work=Veterans at Risk: The Health Effects of Mustard Gas and Lewisite |publisher=The National Academies Press |isbn=0-309-04832-X}}</ref>

== History ==

In 1849, the French chemists [[Jean-François Persoz]] and Bloch, and the German chemist Peter Kremers (1827-?), independently first synthesized thionyl chloride by reacting [[phosphorus pentachloride]] with [[sulfur dioxide]].<ref>See:

* {{cite journal |last1=Persoz |last2=Bloch |title=Des composés binaires formés par les métalloïdes, et, en particulier, de l'action du chloride phosphorique sur les acides sulfureux, sulfurique, phosphorique, chromique, etc. |journal=Comptes rendus |date=1849 |volume=28 |pages=86–88 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015035450975;view=1up;seq=96 |trans-title=Binary compounds formed by metalloids and in particular the action of phosphorus pentachloride on sulfurous acid, sulfuric acid, phosphoric acid, chromic acid, etc. |language=fr}}

* {{cite journal |last1=Persoz |last2=Bloch |title=Addition à une Note précédente concernant les combinaisons du chloride phosphorique avec les acides phosphorique, sulfurique et sulfureux |journal=Comptes rendus |date=1849 |volume=28 |page=389 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015035450975;view=1up;seq=401 |trans-title=Addition to a preceding note concerning compounds of phosphorus pentachloride with phosphoric acid, sulfuric acid, and sulfurous acid |language=fr}}</ref><ref>{{cite journal |last1=Kremers |first1=P. |title=Ueber schwefligsaures Phosphorchlorid |journal=Annalen der Chemie und Pharmacie |date=1849 |volume=70 |issue=3 |pages=297–300 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.hx3bh3;view=1up;seq=703 |trans-title=On sulfurous phosphorus pentachloride |language=de |doi=10.1002/jlac.18490700311}}</ref> However, their products were impure: both Persoz and Kremers claimed that thionyl chloride contained phosphorus,<ref>The German chemist [[Georg Ludwig Carius]] noted that, when the reaction mixture that produced thionyl chloride was distilled, the crude mixture initially released substantial quantities of gas, so that [[phosphoryl chloride]] (POCl₃) was carried into the receiver. {{cite journal |last1=Carius |first1=L. |title=Ueber die Chloride des Schwefels und deren Derivate |journal=Annalen der Chemie und Pharmacie |date=1859 |volume=111 |pages=93–113 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.hx3bhp;view=1up;seq=107 |trans-title=On sulfur chloride and its derivatives |language=de |doi=10.1002/jlac.18591110111}} From p. 94: ''" … dabei ist jedoch die Vorsicht zu gebrauchen, … und nie reines Chlorthionyl erhalten wird."'' ( … however, during that [i.e., the fractional distillation], caution must be used, [so] that one carefully avoids a concentration of hydrogen chloride or excess sulfurous acid in the liquid that is to be distilled, as otherwise, by the evolution of gas that occurs at the start of the distillation, much phosphoryl chloride is transferred and pure thionyl chloride is never obtained.)</ref> and Kremers recorded its boiling point as 100&nbsp;°C (instead of 74.6&nbsp;°C). In 1857, the German-Italian chemist [[Hugo Schiff]] subjected crude thionyl chloride to repeated fractional distillations and obtained a liquid which boiled at 82&nbsp;°C and which he called ''Thionylchlorid''.<ref>{{cite journal |last1=Schiff |first1=Hugo |title=Ueber die Einwirkung des Phosphorsuperchlorids auf einige anorganische Säuren |journal=Annalen der Chemie und Pharmacie |date=1857 |volume=102 |pages=111–118 |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015026321813;view=1up;seq=509 |trans-title=On the reaction of phosphorus pentachloride with some inorganic acids |language=de |doi=10.1002/jlac.18571020116}} The boiling point of thionyl chloride which Schiff observed, appears on p. 112. The name ''Thionylchlorid'' is coined on p. 113.</ref> In 1859, the German chemist [[Georg Ludwig Carius]] noted that thionyl chloride could be used to make [[Organic acid anhydride|acid anhydrides]] and [[acyl chloride]]s from [[carboxylic acid]]s and to make [[Organochloride|alkyl chlorides]] from [[Alcohol (chemistry)|alcohol]]s.<ref>{{cite journal |last1=Carius |first1=L. |title=Ueber die Chloride des Schwefels und deren Derivate |journal=Annalen der Chemie und Pharmacie |date=1859 |volume=111 |pages=93–113 |url=https://babel.hathitrust.org/cgi/pt?id=hvd.hx3bhp;view=1up;seq=107 |trans-title=On sulfur chloride and its derivatives |language=de |doi=10.1002/jlac.18591110111}}

On p. 94, Carius notes that thionyl chloride can be ''" … mit Vortheil zur Darstellung wasserfreier Säuren verwenden."'' ( … used advantageously for the preparation of acid anhydrides.) Also on p. 94, Carius shows chemical equations in which thionyl chloride is used to transform [[benzoic acid]] (OC₇H₅OH) into [[benzoyl chloride]] (ClC₇H₅O) and to transform [[sodium benzoate]] into [[benzoic anhydride]]. On p. 96, he mentions that thionyl chloride will transform [[methanol]] into [[Chloromethane|methyl chloride]] (''Chlormethyl''). Thionyl chloride behaves like [[phosphoryl chloride]]: from pp. 94-95: ''"Die Einwirkung des Chlorthionyls … die Reaction des Chlorthionyls weit heftiger statt."'' (The reaction of thionyl chloride with [organic] substances containing oxygen proceeds in general parallel to that of phosphoryl chloride; where the latter exerts an effect, thionyl chloride usually does so also, only in nearly all cases the reaction occurs far more vigorously.)</ref>

==See also==

* [[Oxalyl chloride]]

* [[Phosphorus pentachloride]]

* [[Phosgene]]

* [[Sulfur dichloride]]

* [[Thionyl bromide]]

==References==

{{reflist|30em}}

{{Chemical agents}}

{{sulfur compounds}}

[[Category:Thionyl compounds]]

[[Category:Sulfur(IV) compounds]]

[[Category:Sulfur oxohalides]]

[[Category:Oxychlorides]]

[[Category:Reagents for organic chemistry]]

[[Category:Lachrymatory agents]]

[[Category:Foul-smelling chemicals]]

[[Category:Inorganic solvents]]