vmelkon - 2-10-2012 at 04:18
Do other salts of permanganate exist besides KMnO4?
I made a solution of FeSO4 and KMnO4 and added them together. The first drop of KMnO4 into the FeSO4 solution did nothing. A few more drops and a
brown precipitate formed. I don't have the means to analyze it.
Fe 2+ gets oxidized by permanganate to Fe 3+ according to
http://www.titrations.info/permanganate-titration-iron
Is the brown stuff Fe(MnO4)3? Fe(OH)3?
What about other transition metals and alkali earth metals?
According to http://en.wikipedia.org/wiki/Calcium_permanganate
calcium permanganate exist in a dry state.
ammonium permanganate exists in a dry state but might explode.
aluminum permanganate exists and so does barium.
ScienceSquirrel - 2-10-2012 at 05:11
The brown precipitate is most likely a mixture of hydrated iron III and manganese II oxides.
The quantitative titration of potassium permanganate requires acidic conditions to go to completion.
I suspect that permanganate salts of all the group I and II metals can be made as they show only one oxidation state.
Similarly, zinc, mercury II, cadmium II, etc.
Cations that are easily oxidised such as iron II will not form stable permanganate salts.