Tellurium hexafluoride is the
inorganic compound
An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bondsthat is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''.
Inorgan ...
of
tellurium
Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally fou ...
and
fluorine
Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extre ...
with the chemical formula TeF
6. It is a colorless and highly toxic gas with an unpleasant odor.
Preparation
Tellurium hexafluoride can be prepared by treating tellurium with
fluorine
Fluorine is a chemical element; it has Chemical symbol, symbol F and atomic number 9. It is the lightest halogen and exists at Standard temperature and pressure, standard conditions as pale yellow Diatomic molecule, diatomic gas. Fluorine is extre ...
gas at 150 °C.
It can also be prepared by fluorination of
TeO3 with
bromine trifluoride. Upon heating,
TeF4 disproportionates to give TeF
6 and Te.
Properties
Tellurium hexafluoride is a highly symmetric octahedral molecule. Its physical properties resemble those of the hexafluorides of
sulfur
Sulfur ( American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms ...
and
selenium
Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elem ...
. It is less
volatile, however, due to the increase in
polarizability
Polarizability usually refers to the tendency of matter, when subjected to an electric field, to acquire an electric dipole moment in proportion to that applied field. It is a property of particles with an electric charge. When subject to an elect ...
. At temperatures below −38 °C, tellurium hexafluoride condenses to a volatile white solid.
File:Tellurium-hexafluoride-xtal-1992-3D-balls.png, Ball-and-stick model of the crystal structure
File:Tellurium-hexafluoride-xtal-1992-3D-SF.png, Space-filling model of the crystal structure
Reactivity
Tellurium hexafluoride is much more chemically
reactive than SF
6.
For example, TeF
6 slowly hydrolyzes to
Te(OH)6:
:TeF
6 + 6 H
2O → Te(OH)
6 + 6 HF
Treatment of tellurium hexafluoride with
tetramethylammonium fluoride (Me
4NF) gives, sequentially, the hepta- and octafluorides:
:TeF
6 + Me
4NF → Me
4NTeF
7
:Me
4NTeF
7 + Me
4NF → (Me
4N)
2TeF
8
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
Web ElementsOSHA
{{fluorine compounds
Tellurium halides
Hexafluorides
Octahedral compounds
Foul-smelling chemicals
Tellurium(VI) compounds