Chemistry:Teflic acid

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Teflic acid
Structural formula
Space-filling model
Names
IUPAC name
Pentafluoroorthotelluric acid
Other names
Teflic acid
Identifiers
3D model (JSmol)
ChemSpider
Properties
HOTeF
5
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)
Hazards
Main hazards corrosive, toxic
GHS pictograms GHS05: Corrosive
GHS Signal word Danger
H314
P260, P264, P280, P301+330+331, P303+361+353, P304+340, P305+351+338, 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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Infobox references
Tracking categories (test):

Teflic acid is a chemical compound with the formula HOTeF
5
. 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 TeO
2
F
2
, but a mixture of volatile telluric compounds, containing HOTeF
5
:[1]

BaTeO
4
+ 10 FSO
2
OH → HOTeF
5
(25%)

Teflic acid can also be prepared from fluorosulfonic acid and barium tellurate:[2]

5 FSO
2
OH + Ba2+[TeO
2
(OH)
4
]2− → HOTeF
5
+ 4 H
2
SO
4
+ BaSO
4

It is also the first hydrolysis product of tellurium hexafluoride:

TeF
6
+ H
2
O → HOTeF
5
+ HF

Teflates

Boron teflate

The conjugate base of teflic acid is called the teflate anion, F
5
TeO
(not to be confused with triflate). Many teflates are known, one example being B(OTeF
5
)
3
, that can be pyrolysed to give acid anhydride O(TeF
5
)
2
.[2]

2 B(OTeF
5
)
3
→ 2 B(OTeF
5
)
2
F + O(TeF
5
)
2

The teflate anion is known to resist oxidation. This property has allowed the preparation several highly unusual species such as the hexateflates M(OTeF
5
)
6
(in which M = As, Sb, Bi). Xenon forms the cation Xe(OTeF
5
)+
.[3]

References

  1. Engelbrecht, A.; Sladky, F. "Pentafluoro-orthotellursaure, HOTeF
    5
    " Angewandte Chemie 1964. 76(9), 379-380, doi:10.1002/ange.19640760912.
  2. 2.0 2.1 Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN:0-12-352651-5.
  3. Mercier, H. P.A.; Sanders, J. C. P.; Schrobilgen, G. J. "The Hexakis(pentafluorooxotellurato)pnictate(V) Anions, M(OTeF
    5
    )
    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.