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Tellurium hexafluoride

Tellurium hexafluoride is the inorganic compound of tellurium and fluorine with the chemical formula TeF<sub>6</sub>. It is a colorless and highly toxic gas with an unpleasant odor.

Preparation

Tellurium hexafluoride can be prepared by treating tellurium with fluorine gas at 150 °C. It can also be prepared by fluorination of TeO<sub>3</sub> with bromine trifluoride. Upon heating, TeF<sub>4</sub> disproportionates to give TeF<sub>6</sub> and Te.

Properties

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

Reactivity

Tellurium hexafluoride is much more chemically reactive than SF<sub>6</sub>. For example, TeF<sub>6</sub> slowly hydrolyzes to Te(OH)<sub>6</sub>:

TeF<sub>6</sub> + 6 H<sub>2</sub>O → Te(OH)<sub>6</sub> + 6 HF

Treatment of tellurium hexafluoride with tetramethylammonium fluoride (Me<sub>4</sub>NF) gives, sequentially, the hepta- and octafluorides:

TeF<sub>6</sub> + Me<sub>4</sub>NF → Me<sub>4</sub>NTeF<sub>7</sub>
Me<sub>4</sub>NTeF<sub>7</sub> + Me<sub>4</sub>NF → (Me<sub>4</sub>N)<sub>2</sub>TeF<sub>8</sub>

Further sources

  • 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.
  • 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.

References

External links