Tellurium tetrafluoride
4219070
189006461
2008-02-04T11:36:35Z
Axiosaurus
3399137
corrected reference to Te2F10 and corrected words on other tellurium fluorides added chem box
{{Chembox new
| ImageFile =
| ImageSize =
| IUPACName = tellurium(IV) fluoride
| OtherNames =
| Section1 = {{Chembox Identifiers
| CASNo = 15192-26-4
| PubChem =
| SMILES =
}}
| Section2 = {{Chembox Properties
| Formula = TeF<sub>4</sub>
| MolarMass = 203.594
| Appearance = white crystalline solid
| Density =
| MeltingPt = 130 °C
| BoilingPt =
| Solubility =
}}
| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
| Autoignition =
}}
}}
'''Tellurium tetrafluoride''', TeF<sub>4</sub>, is a stable, white, hygroscopic crystalline solid and is one of two fluorides of [[tellurium]]. The other binary fluoride is [[tellurium hexafluoride]]<ref name = "Wiberg">''Inorganic Chemistry'',Egon Wiberg, Arnold Frederick Holleman Elsevier 2001 ISBN 0123526515</ref>. The widely reported [[ditellurium decafluoride|Te<sub>2</sub>F<sub>10</sub>]] has been shown to be F<sub>5</sub>TeOTeF<sub>5</sub> <ref name = "Wiberg"/> There are other tellurium compounds that contain fluorine, but only the two mentioned contain solely tellurium and fluorine. Tellurium difluoride, TeF<sub>2</sub>, and ditellurium fluoride, Te<sub>2</sub>F are not known.<ref name = "Wiberg"/>
==Preparation==
Tellurium tetrafluoride can be prepared by the following reaction:<br><br>
[[tellurium dioxide|TeO<sub>2</sub>]] + 2[[sulfur tetrafluoride|SF<sub>4</sub>]] → TeF<sub>4</sub> + 2[[thionyl fluoride|SOF<sub>2</sub>]]
<br><br>
It is also prepared by reacting [[nitryl fluoride]] with tellurium or from the elements at 0 °C or by reacting [[selenium tetrafluoride]] with [[tellurium dioxide]] at 80 °C.<br>
Fluorine in nitrogen can react with [[tellurium dichloride|TeCl<sub>2</sub>]] or [[tellurium dibromide|TeBr<sub>2</sub>]] to form TeF<sub>4</sub>. [[lead(II) fluoride|PbF<sub>2</sub>]] will also fluorinate tellurium to TeF<sub>4</sub>.
==Reactivity==
Tellurium tetrafluoride will react with [[water]] or [[silica]] and forms tellurium oxides. [[Copper]], [[silver]], [[gold]] or [[nickel]] will react with tellurium tetrafluoride at 185 °C. It does not react with [[platinum]]. It is soluble in [[antimony pentafluoride|SbF<sub>5</sub>]] and will precipitate out the complex TeF<sub>4</sub>SbF<sub>5</sub>.
==Properties==
Tellurium tetrafluoride melts at 130 °C and decomposes to [[tellurium hexafluoride]] at 194 °C. In the solid phase it consists of infinite chains of TeF<sub>3</sub>F<sub>2/2</sub> in an octahedral geometry. A lone pair of electrons occupies the sixth position.
==References==
*R.B. King; ''Inorganic Chemistry of Main Group Elements'', VCH Publishers, New York, 1995.
*W.C. Cooper; ''Tellurium'', VanNostrand Reinhold Company, New York, 1971.
<references/>
[[Category:Tellurium compounds]]
[[Category:Fluorides]]