Metal reagent in dehalogenation of vicinal dihalides

In the dehalogenation of vicinal dihalides why can't sodium be taken as a reagent?

I understand that zinc is taken because it is reactive and rate of reaction would be considerably high and it doesn't form complexes. Because of this many other metals can't be used including magnesium as it forms complexes. But I don't understand why sodium can't be taken.

• I don't think you mean "catalyst". Also, please mention the complexes you are talking about (just one or two examples). – Eashaan Godbole Nov 3 '16 at 17:34

You mean something like the following right $$\mathrm{R-X ~+~ Na \longrightarrow R\cdot ~+ ~NaX}$$ and we add a proton source like an alcohole to transfer an H atom to $\mathrm{R\cdot}$: $$\mathrm{R\cdot~ + ~R'-H} \longrightarrow \mathrm{R-H}$$ Well, its in principle possible. But a) you don't want an explosion right?, so be careful as this will probably be very exothermic b) it will probably be really messy as side products like $$2~\mathrm{R\cdot} \longrightarrow \mathrm{R-R}$$ can be formed. Also the whole approach is not really tolerant to pretty much any functional group and will just tear the substrate apart in many cases. The other alternatives (e.g. Zinc, $\mathrm{SmI_2}$) are just much milder, easier to use and much more versatile. But sure, try it out have fun (less than 0.5 g sodium should still be relatively harmless) ; )