Teflic acid

Teflic acid is the chemical compound with the formula HOTeF₅. This strong acid is related to orthotelluric acid, Te(OH)₆. Teflic acid has octahedral geometry and, Ignoring its bent Te-O-H bond, has point group symmetry C_4v.

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Preparation

Teflic acid can be prepared from barium tellurate and fluorosulfonic acid:^[1]

5HOSO₂F + BaO₂Te(OH)₄ → HOTeF₅ + 4 H₂SO₄ + BaSO₄

It is also the first hydrolysis product of tellurium hexafluoride:

TeF₆ + H₂O → HOTeF₅ + HF

Teflates

The conjugate base of teflic acid is called the teflate anion, F₅TeO^- (not to be confused with friflate). Many teflates are known, examples being B(OTF₅)₃ and the acid anhydride O(TeF₅)₂. Pyrolysis of the boron compound gives the dimer (TeF₄O)₂^[1]

2 B(OTF₅)₃ → 2 B(OTF₅)₂F + (OTF₄)₂

The teflate anion is known to resist oxidaton. This property has allowed the preparation several highly unusual species such as the hexateflates M(OTeF₅)₆^- (M = As, Sb, Bi). Xenon forms the cation Xe(OTeF₅)⁺,^[2]

References

1. ^ ^{a b} Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
2. ^ 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.