Tellurium hexafluoride

Tellurium hexafluoride is a chemical compound of tellurium and fluorine with the chemical formula TeF₆. It is a colorless, highly toxic gas with an extremely unpleasant smell.

Preparation

Tellurium hexafluoride is most commonly prepared by passing fluorine gas over tellurium at 150 °C. Below this temperature a mixture of lower fluorides form, including tellurium tetrafluoride and ditellurium decafluoride. It can also be prepared by passing fluorine gas over TeO₃ or indirectly by reacting TeO₂ with SeF₄ to produce TeF₄ and then heating TeF₄ in excess of 200 °C to make TeF₆ and Te.

Properties

Tellurium hexafluoride is a highly symmetric octahedral molecule. Its physical properties resemble the sulfur and selenium analogs. It is less volatile, however, due to the increase in molecular weight. At temperatures below −38 °C, tellurium hexafluoride condenses to a volatile white solid.

Reactivity

Unlike the sulfur analog, tellurium hexafluoride is not chemically inert. This can be attributed to the larger atomic radius which can co-ordinate a maximum of eight atoms rather than six for sulfur and selenium which allows for nucleophilic attack. TeF₆ is hydrolyzed in water to Te(OH)₆ and reacts with Te below 200 °C.

References

1 2 CRC Handbook of Chemistry and Physics, 90. Auflage, CRC Press, Boca Raton, Florida, 2009, ISBN 978-1-4200-9084-0, Section 4, Physical Constants of Inorganic Compounds, p. 4-95.
1 2 3 4 "NIOSH Pocket Guide to Chemical Hazards #0588". National Institute for Occupational Safety and Health (NIOSH).
↑ "Tellurium hexafluoride (as Te)". Immediately Dangerous to Life and Health. National Institute for Occupational Safety and Health (NIOSH).

Literature

W.C. Cooper; Tellurium, Van Nostrand Reinhold Company, New York, USA, 1971.
K.W. Bagnall; The Chemistry of Selenium, Tellurium and Polonium, Elsevier Publishing, New York, 1966.
R.T. Sanderson; Chemical Periodicity, Reinhold, New York, USA, 1960.
N.N. Greenwood and A. Earnshaw; Chemistry of the Elements, 2nd edition, Butterworth, UK, 1997.
F. A. Cotton, G. Wilkinson, C.A. Murillo, and M. Bochmann; Advanced Inorganic Chemistry, John Wiley & Sons, 1999.
G.J. Hathaway, N.H. Proctor; Chemical Hazards of the Workplace, 5th edition, Wiley-Interscience, New Jersey, 2004.

External links

Binary hexafluorides

Known binary hexafluorides

Chalcogen binary hexafluorides	SF₆ SeF₆ TeF₆ PoF₆

Noble gas binary hexafluorides	XeF₆

Transition metal binary hexafluorides	MoF₆ TcF₆ RuF₆ RhF₆ WF₆ ReF₆ OsF₆ IrF₆ PtF₆

Actinide binary hexafluorides	UF₆ NpF₆ PuF₆

Predicted binary hexafluorides

Noble gas binary hexafluorides	KrF₆ RnF₆

Transition metal binary hexafluorides	CrF₆ PdF₆

Actinide binary hexafluorides	AmF₆

Tellurium compounds

Te₂Br TeBr₄ Te₃Cl₂ TeCl₄ TeF₄ TeF₆ TeI₄ TeO TeO₂ TeO₃

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