Re: Chemical synthesis of F2

"Wilco Oelen" <photo@xxxxxxxxx> wrote in message
news:1124559044.097346.283760@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> According to the book "Chemistry of the Elements" by Earnshaw and
> Greenwood, the synthesis is done as follows:
>
> Prepare K2MnF6, using HF only (no F2 needed to synthesize this
> compound). In HF, this manganese (IV) complex is stable. Also prepare
> SbF5, also in HF. The book does not state which antimony compound is
> used as a starting point, but I can imagine that an SbF6(-) compound or
> possibly SbCl5 or Sb2O5 can be used. For manganese I can imagine that
> MnO2 or KMnO4 can be used, but the book does not mention it.
>
> When these are brough together, then the following reaction occurs:
>
> K2MnF6 + 2SbF5 ---> 2KSbF6 + MnF4
>
> Manganese (IV) fluoride is not stable and decomposes to manganese (III)
> fluoride and fluorine gas.
>
> Christe did this experiment in a passivated Teflon-stainless steel
> reactor at 150 C for 1 hour. He had a yield of 40% from the theoretical
> equations, shown above.
>
> All this information can be found at page 821 of the book I mentioned.
>
> Hope this helps,
>
> Wilco

Since this synthesis calls for the use of HF, don't you think it would be
much more direct and simpler to electrolyze anhydrous HF in a divided cell
and collect the F2 that evolves at the (nickel) anode? Anhydrous HF is known
to be a poor electrical conductor because HF is a weak acid so an carrier
electrolyte would be required. The concept of 'chemical synthesis' includes
the concept of electrochemical synthesis so this is a better answer to the
OP's question. If this is meant to be some kind of exercise in 'wet
chemistry' is a malodorous idea because of the toxicity of HF and F2. A
Teflon electrochemical reactor is known as a "Simons cell" and is well known
in the literature.


.