Potassium permanganate
From PyroGuide
Formula: KMnO4
Description: Potassium permanganate is not commonly used in pyrotechnics. Compositions based on permanganates are more sensitive than those based on nitrates and other common oxidizers. It should not be mixed with sulfur. Additionally, it does stain everything it comes in contact with. While it is not incompatible with sulfur in the same way that Chlorates are, it is incompatable with many common organic chemicals, and contamination from such ordinary substances as paper, food or soil could cause extreme sensitivity, especially in the presence of water or high humidity. Though it may be relatively unstable, if used properly, it can be a very useful oxidizer
Hazards: Potassium permanganate is toxic, and breathing protection should be worn when handling fine powder. Also gloves and protective clothing should be warn due to its staining ability. It is also friction sensitive, so extreme care should be taken when mixing it. Do not grind or mill it. When potassium permanganate is mixed with organic materials it may spontaneously ignite. Accidental introduction of this substance into Sulfuric acid results in formation of ozone and extremely unstable Manganese(VII)oxide which violently reacts with most organic substances including many common plastics, paper, wood, and dry skin. It also is explosive by itself.
Other Characteristics: Potassium permanganate powder dropped in water will give it a violet color. If left to evaporate, turns into crystals. This is the recommended use for any pyro's who have bought it mistakenly. Potassium perchlorate or chlorate are much cleaner, safer and easier to handle and are a better alternatives for pyrotechnic use.
[edit] A word of additional legal caution for those of you residing in the USA
KMnO4 can be used to produce illicit substances. Consequently, the DEA has restricted its use and sale by classifying it as a List I controlled precursor. Potassium permanganate is listed as a Table I precursor under the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances. This makes it very difficult to find in California.
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