Tin(IV) chloride
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| Names | |||
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| IUPAC names
Tetrachlorostannane
Tin tetrachloride Tin(IV) chloride | |||
| Other names
Stannic chloride
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| Identifiers | |||
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3D model (JSmol)
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| ECHA InfoCard | 100.028.717 | ||
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PubChem CID
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| UNII | |||
| UN number | 1827 | ||
CompTox Dashboard (EPA)
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| Properties | |||
| SnCl4 | |||
| Molar mass | 260.50 g/mol (anhydrous) 350.60 g/mol (pentahydrate) | ||
| Appearance | Colorless to slightly yellow 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 | |||
Refractive index (nD)
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1.512 | ||
| Structure | |||
| monoclinic (P21/c) | |||
| Hazards | |||
| NFPA 704 (fire diamond) | |||
| Safety data sheet (SDS) | ICSC 0953 | ||
| Related compounds | |||
Other anions
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Tin(IV) fluoride Tin(IV) bromide Tin(IV) iodide | ||
Other cations
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Carbon tetrachloride Silicon tetrachloride Germanium tetrachloride Tin(II) chloride Lead(IV) 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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Tin(IV) chloride, also known as tin tetrachloride or stannic chloride, is an inorganic compound 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.
Preparation
It is prepared from reaction of chlorine gas with tin at 115 °C (239 °F).
- Sn + 2 Cl2 → SnCl4
Structure
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]
Hydrates
Several hydrates of tin tetrachloride are known. 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]
Reactions
Aside from water, other Lewis bases form adducts. These include ammonia and organophosphines. With hydrochloric acid the complex [SnCl6]2− is formed making the so-called hexachlorostannic acid.[1]
Precursor to organotin compounds
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 more useful than the tetraorganotin derivatives.
Applications in high organic synthesis
Although a specialized application, SnCl4 is used in Friedel-Crafts reactions as a Lewis acid catalyst for alkylation and cyclisation.[1] Stannic chloride is used in chemical reactions with fuming (90%) nitric acid for the selective nitration of activated aromatic rings in the presence of inactivated ones.[6]
Uses
The main application of SnCl4 is as a precursor to organotin compounds, which are used as catalysts and polymer stabilizers.[7] It can be used in a sol-gel process to prepare SnO2 coatings (for example for toughening glass); nanocrystals of SnO2 can be produced by refinements of this method.
Safety
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 substituted for by a mixture of silicon tetrachloride and titanium tetrachloride near the end of the war due to shortages of tin.[8]
References
- ^ a b c Egon Wiberg, Arnold Frederick Holleman (2001). Inorganic Chemistry. Elsevier. ISBN 0-12-352651-5.
- ^ 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.
- ^ 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.
- ^ Genge, Anthony R. J.; Levason, William; Patel, Rina; Reid, Gillian; Webster, Michael (2004). "Hydrates of tin tetrachloride". Acta Crystallographica Section C. 60 (4): i47–i49. doi:10.1107/S0108270104005633. PMID 15071197.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- ^ 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.
- ^ 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
- ^ Fries, Amos A. (2008). Chemical Warfare. Read. pp. 148–49, 407. ISBN 978-1-4437-3840-8..
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