Tin(IV) chloride, also known as tin tetrachloride or stannic chloride, is an inorganic compound of tin and chlorine with the formula SnCl4. It is a colorless hygroscopic liquid, which fumes on contact with air. It is used as a precursor to other tin compounds.[1] It was first discovered by Andreas Libavius (1550–1616) and was known as spiritus fumans libavii.

Tin(IV) chloride
Tin (IV) chloride
Tin (IV) chloride
Anhydrous Tin(IV) chloride
Tin(IV) chloride pentahydrate.jpg
Tin(IV) chloride pentahydrate.jpg
Tin(IV) chloride pentahydrate
Names
IUPAC names
Tetrachlorostannane
Tin tetrachloride
Tin(IV) chloride
Other names
Stannic chloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.028.717 Edit this at Wikidata
EC Number
  • 231-588-9
RTECS number
  • XP8750000
UNII
UN number 1827
  • InChI=1S/4ClH.Sn/h4*1H;/q;;;;+4/p-4 checkY
    Key: HPGGPRDJHPYFRM-UHFFFAOYSA-J checkY
  • InChI=1/4ClH.Sn/h4*1H;/q;;;;+4/p-4
    Key: HPGGPRDJHPYFRM-XBHQNQODAC
  • anhydrous: Cl[Sn](Cl)(Cl)Cl
  • pentahydrate: Cl[Sn-2](Cl)(Cl)([OH2+])([OH2+])Cl.O.O.O
Properties
SnCl4
Molar mass 260.50 g/mol (anhydrous)
350.60 g/mol (pentahydrate)
Appearance Colorless fuming liquid
Odor Acrid
Density 2.226 g/cm3 (anhydrous)
2.04 g/cm3 (pentahydrate)
Melting point −34.07 °C (−29.33 °F; 239.08 K) (anhydrous)
56 °C (133 °F; 329 K) (pentahydrate)
Boiling point 114.15 °C (237.47 °F; 387.30 K)
hydrolysis,very hygroscopic (anhydrous)
very soluble (pentahydrate)
Solubility soluble in alcohol, benzene, toluene, chloroform, acetone, kerosene, CCl4, methanol, gasoline, CS2
Vapor pressure 2.4 kPa
−115·10−6 cm3/mol
1.512
Structure
monoclinic (P21/c)
Hazards
GHS labelling:
GHS05: Corrosive
Danger
H314, H412
P260, P264, P273, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
3
0
1
Safety data sheet (SDS) ICSC 0953
Related compounds
Other anions
Tin(IV) fluoride
Tin(IV) bromide
Tin(IV) iodide
Other cations
Carbon tetrachloride
Silicon tetrachloride
Germanium tetrachloride
Lead(IV) chloride
Related compounds
Tin(II) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation

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It is prepared from reaction of chlorine gas with tin at 115 °C (239 °F):

Sn + 2Cl
2
SnCl
4

Structure

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Anhydrous tin(IV) chloride solidifies at −33 °C to give monoclinic crystals with the P21/c space group. It is isostructural with SnBr4. The molecules adopt near-perfect tetrahedral symmetry with average Sn–Cl distances of 227.9(3) pm.[2]

 
Space-filling model of anhydrous SnCl4.
 
Structure of solid SnCl4.

Reactions

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Tin(IV) chloride is well known as a Lewis acid. Thus it forms hydrates. The pentahydrate SnCl4·5H2O was formerly known as butter of tin. They all consist of [SnCl4(H2O)2] molecules together with varying amounts of water of crystallization. The additional water molecules link together the molecules of [SnCl4(H2O)2] through hydrogen bonds.[3] Although the pentahydrate is the most common hydrate, lower hydrates have also been characterised.[4]

Aside from water, other Lewis bases form adducts with SnCl4. These include ammonia and organophosphines. The complex [SnCl6]2− is formed with hydrochloric acid making hexachlorostannic acid.[1]

Applications

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Precursor to organotin compounds

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Anhydrous tin(IV) chloride is a major precursor in organotin chemistry. Upon treatment with Grignard reagents, tin(IV) chloride gives tetraalkyltin compounds:[5]

SnCl4 + 4 RMgCl → SnR4 + 4 MgCl2

Anhydrous tin(IV) chloride reacts with tetraorganotin compounds in redistribution reactions:

SnCl4 + SnR4 → 2 SnCl2R2

These organotin halides are useful precursors to catalysts (e.g., dibutyltin dilaurate) and polymer stabilizers.[6]

Organic synthesis

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SnCl4 is used in Friedel–Crafts reactions as a Lewis acid catalyst.[1] For example, the acetylation of thiophene to give 2-acetylthiophene is promoted by tin(IV) chloride.[7] Similarly, tin(IV) chloride is useful for the nitrations.[8]

Safety

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Stannic chloride was used as a chemical weapon in World War I, as it formed an irritating (but non-deadly) dense smoke on contact with air. It was supplanted by a mixture of silicon tetrachloride and titanium tetrachloride near the end of the war due to shortages of tin.[9]

References

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  1. ^ a b c Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman (2001). Inorganic Chemistry. Elsevier. ISBN 0-12-352651-5.{{cite book}}: CS1 maint: multiple names: authors list (link)
  2. ^ Reuter, Hans; Pawlak, Rüdiger (April 2000). "Die Molekül- und Kristallstruktur von Zinn(IV)-chlorid". Zeitschrift für anorganische und allgemeine Chemie (in German). 626 (4): 925–929. doi:10.1002/(SICI)1521-3749(200004)626:4<925::AID-ZAAC925>3.0.CO;2-R.
  3. ^ Barnes, John C.; Sampson, Hazel A.; Weakley, Timothy J. R. (1980). "Structures of di-μ-hydroxobis[aquatrichlorotin(IV)]-1,4-dioxane(1/3), di-μ-hydroxobis[aquatrichlorotin(IV)]-1,8-epoxy-p-menthane(1/4), di-m-hydroxobis[aquatribromotin(IV)]-1,8-epoxy-p-menthane(1/4), di-μ-hydroxobis[aquatrichlorotin(IV)], and cis-diaquatetrachlorotin(IV)". J. Chem. Soc., Dalton Trans. (6): 949. doi:10.1039/DT9800000949.
  4. ^ Genge, Anthony R. J.; Levason, William; Patel, Rina; et al. (2004). "Hydrates of tin tetrachloride". Acta Crystallographica Section C. 60 (4): i47–i49. doi:10.1107/S0108270104005633. PMID 15071197.
  5. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  6. ^ G. G. Graf "Tin, Tin Alloys, and Tin Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2005 Wiley-VCH, Weinheim. doi:10.1002/14356007.a27_049
  7. ^ John R. Johnson, G. E. May (1938). "2-Acetothienone". Organic Syntheses. 18: 1. doi:10.15227/orgsyn.018.0001.
  8. ^ Thurston, David E.; Murty, Varanasi S.; Langley, David R.; Jones, Gary B. (1990). "O-Debenzylation of a Pyrrolo[2,1-c][1,4]benzodiazepine in the Presence of a Carbinolamine Functionality: Synthesis of DC-81". Synthesis. 1990: 81–84. doi:10.1055/s-1990-26795. S2CID 98109571.
  9. ^ Fries, Amos A. (2008). Chemical Warfare. Read. pp. 148–49, 407. ISBN 978-1-4437-3840-8..
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