Tellurium(VI) fluoride

Tellurium(VI) fluoride, also known as tellurium hexafluoride, is a chemical compound. Its chemical formula is TeF6. It contains tellurium in its +6 oxidation state. It also contains fluoride ions. It is the oldest known tellurium fluoride.
Properties.
Tellurium(VI) fluoride is a colorless gas. It condenses to a white solid when made cold. It has a very bad smell. It is very toxic. It is similar to selenium hexafluoride, even though it is less volatile (not as easily evaporated). It reacts with water to make telluric acid and hydrofluoric acid. It reacts with tellurium under to make tellurium tetrafluoride. 
Preparation.
It is made by reacting hot fluorine with tellurium. Cold fluorine gas makes tellurium tetrafluoride. It can also be made by reacting fluorine with tellurium trioxide. Another way to make it is reacting selenium tetrafluoride and tellurium dioxide to make tellurium tetrafluoride, which is heated above to make tellurium hexafluoride and tellurium.