Tellurium tetrachloride

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Tellurium tetrachloride
Image:Tellurium tetrachloride.jpg
IUPAC name	Tellurium(IV) chloride Tetratellurium hexadecachloride
Other names	Tellurium chloride
Identifiers
CAS number	[10026-07-0]
Properties
Molecular 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
Boiling point	380 °C
Structure
Coordination geometry	Distorted octahedral (Te)
Molecular shape	Seesaw
Dipole moment	2.59 D
Hazards
Main hazards	Highly 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 noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Tellurium tetrachloride is a covalent compound of tellurium and chlorine that is somewhat volatile, subliming at 200 °C at 0.1 mmHg. It exists as the tetramer, Te₄Cl₁₆, in the solid state, which 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.^[1]. In the liquid it is good conductor dissociating into ions TeCl³⁺ and Cl⁻.^[1] In the vapour phase it is monomeric with a structure similar to SF₄.^[2]

TeCl₄ has proven of occasional interest in organic synthesis.^[3] 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 give TeC₂(C₆H₄OMe)₂ which can be reduced to the diaryl telluride.

[edit] Safety considerations

As is the case for other tellurium compounds, TeCl₄ is toxic and should be handled in a fume cupboard. It also releases HCl upon hydrolysis.

[edit] References

1. ^ ^{a b} Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4. 
2. ^ Cotton, F. Albert; Wilkinson, Geoffrey; Murillo, Carlos A.; Bochmann, Manfred (1999). Advanced Inorganic Chemistry (6th Edn.) New York:Wiley-Interscience. ISBN 0-471-19957-5.
3. ^ Petragnani, N.; Comasseto, J. V. Synthesis 1991, 793, 897