Teflic acid


Teflic acid is the chemical compound with the formula HOTeF5. This strong acid is related to orthotelluric acid, Te6. Teflic acid has a slightly distorted octahedral 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, i.a. HOTeF5:
Teflic acid can also be prepared from fluorosulfonic acid and barium tellurate:
It is also the first hydrolysis product of tellurium hexafluoride:

Teflates

The conjugate base of teflic acid is called the teflate anion, F5TeO−. Many teflates are known, examples being B3 and the acid anhydride O2. Pyrolysis of the boron compound gives the dimer 2
The teflate anion is known to resist oxidation. This property has allowed the preparation several highly unusual species such as the hexateflates M6−. Xenon forms the cation Xe+.