Tellurium tetrafluoride

Tellurium tetrafluoride

Names
IUPAC name tellurium(IV) fluoride
Identifiers
CAS Number	15192-26-4 Y
PubChem CID	167258
CompTox Dashboard (EPA)	DTXSID80934374
Properties
Chemical formula	TeF4
Molar mass	203.594
Appearance	white crystalline solid
Melting point	129 °C (264 °F; 402 K)
Related compounds
Other anions	tellurium dioxide, tellurium tetrachloride, tellurium(IV) bromide, tellurium(IV) iodide
Other cations	sulfur tetrafluoride, selenium tetrafluoride
Related compounds	tellurium hexafluoride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Tellurium tetrafluoride, TeF₄, is a stable, white, hygroscopic crystalline solid and is one of two fluorides of tellurium. The other binary fluoride is tellurium hexafluoride.^[1] The widely reported Te₂F₁₀ has been shown to be F₅TeOTeF₅ ^[1] There are other tellurium compounds that contain fluorine, but only the two mentioned contain solely tellurium and fluorine. Tellurium difluoride, TeF₂, and ditellurium difluoride, Te₂F₂ are not known.^[1]

Preparation

Tellurium tetrafluoride can be prepared by the following reaction:

TeO₂ + 2SF₄ → TeF₄ + 2SOF₂

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.
Fluorine in nitrogen can react with TeCl₂ or TeBr₂ to form TeF₄. PbF₂ will also fluorinate tellurium to TeF₄.

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 SbF₅ and will precipitate out the complex TeF₄SbF₅.

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 TeF₃F_2/2 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.