Teflic acid is a chemical compound with the formula HOTeF5. This strong acid is related to orthotelluric acid, Te(OH)6. Teflic acid has a slightly distorted octahedral molecular geometry.

Preparation

Teflic acid was accidentally discovered by Engelbrecht and Sladky. Their synthesis did not yield the anticipated telluryl fluoride TeO2F2, but a mixture of volatile telluric compounds, containing HOTeF5:[2]

BaTeO4 + 10 FSO2OH → HOTeF5 (25%)

Teflic acid can also be prepared from fluorosulfonic acid and barium tellurate:[3]

5 FSO2OH + Ba2+[TeO2(OH)4]2− → HOTeF5 + 4 H2SO4 + BaSO4

It is also the first hydrolysis product of tellurium hexafluoride:

TeF6 + H2O → HOTeF5 + HF

Teflates

Boron teflate

The conjugate base of teflic acid is called the teflate anion, F5TeO− (not to be confused with triflate). Many teflates are known, one example being B(OTeF5)3, that can be pyrolysed to give acid anhydride O(TeF5)2.[3]

2 B(OTeF5)3 → 2 B(OTeF5)2F + O(TeF5)2

The teflate anion is known to resist oxidation. This property has allowed the preparation several highly unusual species such as the hexateflates M(OTeF5)−6 (in which M = As, Sb, Bi). Xenon forms the cation Xe(OTeF5)+.[4]

References

  1. ^ Perrin, D. D., ed. (1982) [1969]. Ionisation Constants of Inorganic Acids and Bases in Aqueous Solution. IUPAC Chemical Data (2nd ed.). Oxford: Pergamon (published 1984). Entry 220. ISBN 0-08-029214-3. LCCN 82-16524.
  2. ^ Engelbrecht, A.; Sladky, F. "Pentafluoro-orthotellursaure, HOTeF5" Angewandte Chemie 1964. 76(9), 379-380, doi:10.1002/ange.19640760912.
  3. ^ a b Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
  4. ^ Mercier, H. P.A.; Sanders, J. C. P.; Schrobilgen, G. J. "The Hexakis(pentafluorooxotellurato)pnictate(V) Anions, M(OTeF5)−6 (M = As, Sb, Bi): A Series of Very Weakly Coordinating Anions" Journal of the American Chemical Society, volume 116, 2921, (1994). doi:10.1021/ja00086a025.

Further reading

  • R.B. King; Inorganic Chemistry of Main Group Elements, VCH Publishers, New York,1994.
Allikas: http://en.wikipedia.org/wiki/Teflate
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