Tellurium tetrachloride

Tellurium tetrachloride
Names
	IUPAC names Tellurium(IV) chloride; Tetratellurium hexadecachloride
	Other names Tellurium chloride
Identifiers
CAS Number	10026-07-0 ;
3D model (JSmol)	Interactive image;
ChemSpider	55367 ;
ECHA InfoCard	100.030.038
PubChem CID	61443;
UNII	DNY2R5498H ;
CompTox Dashboard (EPA)	DTXSID1064904 ;
	InChI InChI=1S/Cl4Te/c1-5(2,3)4 Key: SWLJJEFSPJCUBD-UHFFFAOYSA-N ; InChI=1/Cl4Te/c1-5(2,3)4 Key: SWLJJEFSPJCUBD-UHFFFAOYAL;
	SMILES Cl[Te](Cl)(Cl)Cl;
Properties
Chemical formula	[TeCl4]4
Molar mass	1077.64 g/mol
Appearance	hygroscopic pale yellow solid; (if fused, maroon liquid)
Density	3.26 g/cm3, solid
Melting point	224 °C (435 °F; 497 K)
Boiling point	380 °C (716 °F; 653 K)
Structure
Crystal structure	Monoclinic, mS80
Space group	C12/c1, No. 15
Coordination geometry	Distorted octahedral (Te)
Molecular shape	Seesaw (gas phase)
Dipole moment	2.59 D (gas phase)
Hazards
Main hazards	Toxic, corrosive,; respiratory irritant
Related compounds
Other anions	Tellurium tetrafluoride; Tellurium tetrabromide; Tellurium tetraiodide
Other cations	Selenium tetrachloride; Polonium tetrachloride
Related compounds	Tellurium dichloride
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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	Infobox references

Tellurium tetrachloride is the inorganic compound with the empirical formula TeCl₄. The compound is volatile, subliming at 200 °C at 0.1 mmHg.[1] Molten TeCl₄ is ionic, dissociating into TeCl₃⁺ and Te₂Cl₁₀²⁻.[1]

Structure

TeCl₄ is monomeric in the gas phase, with a structure similar to that of SF₄.[2] In the solid state, it is a tetrameric cubane-type cluster, consisting of a Te₄Cl₄ core and three terminal chloride ligands for each Te. Alternatively, this tetrameric structure can be considered as a Te₄ tetrahedron with face-capping chlorines and three terminal chlorines per tellurium atom, giving each tellurium atom a distorted octahedral environment

Synthesis

TeCl₄ is prepared by chlorination of tellurium powder:

Te + 2 Cl₂ → TeCl₄

The reaction is initiated with heat. The product is isolated by distillation.[3]

Applications

TeCl₄ is of occasional interest in organic synthesis.[4] It adds to alkenes to give Cl-C-C-TeCl₃ derivatives, wherein the Te can be subsequently removed with sodium sulfide. Electron-rich arenes react to give aryl Te compounds. Thus, anisole gives TeCl₂(C₆H₄OMe)₂, which can be reduced to the diaryl telluride.

Safety considerations

As is the case for other tellurium compounds, TeCl₄ is toxic. It also releases HCl upon hydrolysis.

References

Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5
Suttle, J. F.; Smith, C. R. F. (1950). Audrieth, Ludwig F. (ed.). Tellurium(IV) chloride. Inorganic Syntheses. 3. pp. 140–2. doi:10.1002/9780470132340. ISBN 978-0-470-13162-6.CS1 maint: multiple names: authors list (link)
Petragnani, N.; Comasseto, J. V. (1991). "Tellurium Reagents in Organic Synthesis; Recent Advances. Part 1". Synthesis. 1991 (10): 793–817. doi:10.1055/s-1991-26577. and Petragnani, N.; Comasseto, J. V. (1991). "Tellurium Reagents in Organic Synthesis; Recent Advances. Part 2". Synthesis. 1991 (11): 897–919. doi:10.1055/s-1991-26605.

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[Greenwood-1] Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.

[2] Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999), Advanced Inorganic Chemistry (6th ed.), New York: Wiley-Interscience, ISBN 0-471-19957-5

[3] Suttle, J. F.; Smith, C. R. F. (1950). Audrieth, Ludwig F. (ed.). Tellurium(IV) chloride. Inorganic Syntheses. 3. pp. 140–2. doi:10.1002/9780470132340. ISBN 978-0-470-13162-6.CS1 maint: multiple names: authors list (link)

[4] Petragnani, N.; Comasseto, J. V. (1991). "Tellurium Reagents in Organic Synthesis; Recent Advances. Part 1". Synthesis. 1991 (10): 793–817. doi:10.1055/s-1991-26577. and Petragnani, N.; Comasseto, J. V. (1991). "Tellurium Reagents in Organic Synthesis; Recent Advances. Part 2". Synthesis. 1991 (11): 897–919. doi:10.1055/s-1991-26605.