Polumna Posted April 2, 2007 Share Posted April 2, 2007 hi dudes i have got one question. Today I bought some Kmno4 from pharmacie for 40cents per 10g.Then i was grinding it down in a mortar while wearing a dust mask.then i remember that i have got some kmno4 left on my shelf, i pour it on a sheet of paper and compared to the new permanganate it looks brownish/black. Can I use the old permanganate for anything now or shouldn´t i use it??? thanx for your advices Polumna Link to comment Share on other sites More sharing options...
asilentbob Posted April 2, 2007 Share Posted April 2, 2007 Its probably slightly decomposed to MnO2. Consider that KMnO4 really has no place in pyrotechnics. Chemistry experiments, yes, but not in pyrotechnics. However, yeah it should work fine. Link to comment Share on other sites More sharing options...
Polumna Posted April 2, 2007 Author Share Posted April 2, 2007 hi dude The Kmno4 also smells a bit amazing after opening the glassjar.maybe it is a gas??? Polumna Link to comment Share on other sites More sharing options...
Mumbles Posted April 3, 2007 Share Posted April 3, 2007 It may or may not be a gas. Oxygen, or ozone most likely. As for the brown permanganate, yes it appears to be MnO2 or something. Decomposition to the Manganate is not uncommon, (formula below). There isn;t anything you shouldn't use the decomposed stuff compared to the fresh stuff, as I wouldn't recomend you using it for anything at all. Just goes to show you the instability of the stuff. 2 KMnO4 ---> K2MnO4 + MnO2 + O2 Link to comment Share on other sites More sharing options...
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