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Teflic acid

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Teflic acid
Structural formula
Space-filling model
Space-filling model
Names
IUPAC name
Pentafluoroorthotelluric acid
Other names
Teflic acid
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.161.534 Edit this at Wikidata
  • InChI=1S/F5HOTe/c1-7(2,3,4,5)6/h6H checkY
    Key: OAOSLENTGBMCNC-UHFFFAOYSA-N checkY
  • InChI=1/F5HOTe/c1-7(2,3,4,5)6/h6H
    Key: OAOSLENTGBMCNC-UHFFFAOYAO
  • F[Te](F)(F)(F)(F)O
Properties
HOTeF5
Molar mass 239.60 g·mol−1
Appearance colorless solid
Melting point 39.1 °C (102.4 °F; 312.2 K)
Boiling point 59.7 °C (139.5 °F; 332.8 K)
Acidity (pKa) 8.8 (in Ac2O)[1]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
corrosive, toxic
GHS labelling:
GHS05: Corrosive
Danger
H314
P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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

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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

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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

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  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

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  • R.B. King; Inorganic Chemistry of Main Group Elements, VCH Publishers, New York,1994.