Tellurium tetrachloride

Tellurium tetrachloride
IUPAC name Tellurium(IV) chloride Tetratellurium hexadecachloride
Other names Tellurium chloride
Identifiers
CAS number	10026-07-0
PubChem	61443
ChemSpider	55367 Y
Jmol-3D images	Image 1
SMILES Cl[Te](Cl)(Cl)Cl
InChI InChI=1S/Cl4Te/c1-5(2,3)4 Y Key: SWLJJEFSPJCUBD-UHFFFAOYSA-N Y InChI=1/Cl4Te/c1-5(2,3)4 Key: SWLJJEFSPJCUBD-UHFFFAOYAL
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
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
Y tetrachloride (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Tellurium tetrachloride is the inorganic compound with the empirical formula TeCl₄. The compound is volatile, subliming at 200 °C at 0.1 mm Hg^[1]. Molten TeCl₄ is ionic, dissociating into ions 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 cluster, Te₄Cl₁₆. The cluster with a Te₄Cl₄ core and three terminal chloride ligands for each Te. Alternatively it 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 has proven 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 give 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

1. ^ ^{a b} Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419. 
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). "Tellurium(IV) chloride". Inorganic Syntheses 3: 140–2. doi:10.1002/9780470132340. ISBN 9780470131626. 
4. ^ Petragnani, N.; Comasseto, J. V. Synthesis 1991, 793, 897