Potassium permanganate is an inorganic compound with the chemical formula KMnO4. It is a purplish-black crystalline salt, which dissolves in water as and ions to give an intensely pink to purple solution.
Potassium permanganate is widely used in the chemical industry and laboratories as a strong oxidizing agent, and also traditionally as a medication for dermatitis, for cleaning wounds, and general disinfection. It is on the World Health Organization's List of Essential Medicines. It has a great variety of niche uses such as biocide for water treatment purposes and for tanning and dyeing cloth. In 2025, global potassium permanganate market reached 360,100 metric tons.
It is also referred to as chameleon mineral, Condy's crystals, permanganate of potash, hypermangan, purple potion powder, permanganic acid (potassium salt), and purple salt.
Properties Potassium permanganate is the potassium salt of the tetrahedral transition metal oxo complex permanganate, in which four ligands are bound to a manganese(VII) center. Potassium permanganate is odorless and slightly sweet and astringent in taste. It is soluble in water, sulfuric acid, acetic anhydride, and benzonitrile, but dissolves best in methanol and acetone.
Structure forms orthorhombic crystals with constants: a = 910.5 pm, b = 572.0 pm, c = 742.5 pm. The overall motif is similar to that for barium sulfate, with which it forms solid solutions. In the solid (as in solution), each centre is tetrahedral. The Mn–O distances are 1.62 Å.
Color The purplish-black color of solid potassium permanganate, and the intensely pink to purple color of its solutions, is caused by its permanganate anion, which gets its color from a strong charge-transfer absorption band caused by excitation of electrons from oxo ligand orbitals to empty orbitals of the manganese(VII) center. The crystal form can range from purple to black or gray, and has a blue metallic sheen.
Medical uses
Mechanism of action Potassium permanganate functions as a strong oxidizing agent. Through this mechanism it results in disinfection, astringency, and reduced odors.
Clinical use Potassium permanganate is no longer the preferred treatment for dermatological conditions and no form of it is labeled for human use by the US Food and Drug Administration. It should never be taken internally, because it is highly toxic and corrosive to mucous membranes and skin.
Traditionally potassium permanganate was prescribed for a number of skin conditions, including fungal infections of the foot, impetigo, pemphigus, superficial wounds, dermatitis, and topical ulcers. Also accessible via WHO Publications. Radioactive contamination of the skin could be cleaned with potassium permanganate and vigorous scrubbing. For topical ulcers it was used together with procaine benzylpenicillin. Typically it was used in skin conditions that produce a lot of liquid. It could be applied as a soaked dressing or a bath. Petroleum jelly may be used on the nails before soaking to prevent their discoloration. For treating eczema, it was recommended using for only a few days at a time due to irritating the skin.
The US Food and Drug Administration does not recommend its use in the crystal or tablet form. It should only be used in a diluted liquid form.
Historical use Potassium permanganate was first made in the 1600s and came into common medical use at least as early as the 1800s. During World War I Canadian soldiers were given potassium permanganate (to be applied mixed with an ointment) in an effort to prevent sexually transmitted infections. Some have attempted to bring about an abortion by putting it in the vagina, though this is not effective. Other historical uses have included an effort to wash out the stomach in those with strychnine or picrotoxin poisoning.
Side effects Side effects from topical use include irritation of the skin and discoloration of clothing. A harsh burn on a child from an undissolved tablet has been reported. Higher concentration solutions can result in chemical burns. Therefore, in 2015 the British National Formulary recommended 100 mg be dissolved in a liter of water before use to form a 1:10,000 (0.01%) solution. Wrapping the dressings soaked with potassium permanganate is not recommended.
Toxicology
Potassium permanganate is toxic if taken by mouth. Concentrated solutions when drunk have resulted in acute respiratory distress syndrome or swelling of the airway. Effects may include nausea, vomiting, and shortness of breath. If a sufficiently large amount (about 10 grams) is eaten death may occur. Concentrated solutions of potassium permanganate and repeated exposure cause skin corrosion and dermatitis.
Recommended measures for those who have ingested potassium permanganate include gastroscopy. Activated charcoal or medications to cause vomiting are not recommended. While medications like ranitidine and acetylcysteine may be used in toxicity, evidence for this use is poor.
Pharmaceuticals In the United States the FDA requires tablets of the medication to be sold by prescription. Potassium permanganate, however, does not have FDA approved uses and therefore non medical grade potassium permanganate is sometimes used for medical purposes.
It is available under a number of brand names including Permasol, Koi Med Tricho-Ex, and Kalii permanganas RFF. It is occasionally called "Condy's crystals".
Veterinary medicine Potassium permanganate may be used to prevent the spread of glanders among horses.
Industrial and other uses Almost all applications of potassium permanganate exploit its oxidizing properties. As a strong oxidant that does not generate toxic byproducts, has many niche uses.
Water treatment Potassium permanganate is used extensively in the water treatment industry. It is used to remove iron and hydrogen sulfide (rotten egg smell) from well water via a "manganese greensand" filter. "Pot-Perm" is also obtainable at pool supply stores and is used additionally to treat wastewater. Historically it was used to disinfect drinking water, though the EPA considers it a poor disinfectant. It can turn water a fuchsia or pink color. Modern hiking and survivalist guides advise against using potassium permanganate in the field because it is difficult to dose correctly.
Fisheries and aquatic management
Potassium permanganate is not FDA approved for use with food fish in the United States, however it is categorized under "regulatory action deferred" and is legal to use because the FDA considers it "low regulatory priority" and at low risk for adverse human health effects.: "At the time of this writing, FDA has also given copper sulfate (CuSO 4) and potassium permanganate (KMnO4) deferred status, which means that these treatments may be used without legal prosecution, but they may lose deferred status if evidence is found of any danger to the human consumer."
Potassium permanganate is a treatment for Ichthyophthirius multifiliis (commonly known as "ich") and protozoa (such as Trichodina), which infect and usually kill freshwater aquarium fish. A minimum dose of 2 ppm is required. Water with more organic load and a higher number of organisms including algae requires more permanganate. High concentrations and use more than once per week kill fish. Food fish require a 7-day period after treatment before they can be consumed.
An alternative application is in the control of nuisance organisms such as zebra mussels in freshwater collection and treatment systems.
Rotenone can be deactivated in water with the use of potassium permanganate to lower toxicity to acceptable levels. A 1:1 ratio of permanganate to rotenone is insufficient to deactivate rotenone in most situations.
Synthesis of organic compounds
KMnO4 is a reagent for the synthesis of organic compounds. Significant amounts are used in the commercial synthesis of ascorbic acid, chloramphenicol, saccharin, isonicotinic acid, and pyrazinoic acid.
is used in qualitative organic analysis to test for the presence of unsaturation. It is sometimes referred to as Baeyer's reagent after the German organic chemist Adolf von Baeyer. The reagent is an alkaline solution of potassium permanganate. Reaction with double or triple bonds ( or ) causes the color to fade from purplish-pink to brown. Aldehydes and formic acid (and formates) also give a positive test. The test is antiquated.
solution is a common thin layer chromatography (TLC) stain for the detection of oxidizable functional groups, such as alcohols, aldehydes, alkenes, and ketones. Such compounds result in a white to orange spot on TLC plates.
Analytical use Potassium permanganate can be used to quantitatively determine the total oxidizable organic material in an aqueous sample. The value determined is known as the permanganate value. In analytical chemistry, a standardized aqueous solution of is sometimes used as an oxidizing titrant for redox titrations (permanganometry). As potassium permanganate is titrated, the solution becomes a light shade of purple, which darkens as excess of the titrant is added to the solution. In a related way, it is used as a reagent to determine the Kappa number of wood pulp. For the standardization of solutions, reduction by oxalic acid is often used. In agricultural chemistry, it is used for estimation of active carbon in soil.
Aqueous, acidic solutions of are used to collect gaseous mercury in flue gas during stationary source emissions testing.Code of Federal Regulations(7-1-07) Edition, Title 40, Part 60, Appendix A-8, Method 29, Section 7.3.1
In histology, potassium permanganate was used as a bleaching agent.
Fruit preservation Ethylene absorbents extend storage time of bananas even at high temperatures. This effect can be exploited by packing bananas in polyethylene together with potassium permanganate. By removing ethylene by oxidation, the permanganate delays the ripening, increasing the fruit's shelf life up to 4 weeks without the need for refrigeration.
The chemical reaction, in which ethylene (C2H4) is oxidised by potassium permanganate () to carbon dioxide (), manganese oxide (MnO2) and potassium hydroxide (KOH), in the presence of water, is presented as follows:
Survival kits Potassium permanganate is sometimes included in survival kits: as a hypergolic fire starter (when mixed with glycerol antifreeze from a car radiator); as a water sterilizer; and for creating distress signals on snow. Modern hiking and survivalist guides advise against using potassium permanganate in the field because it is difficult to dose correctly.
Fire service Potassium permanganate is added to "plastic sphere dispensers" to create backfires, burnouts, and controlled burns. Polymer spheres resembling ping-pong balls containing small amounts of permanganate are injected with ethylene glycol and projected towards the area where ignition is desired, where they spontaneously ignite seconds later. Both handheld helicopter- unmanned aircraft systems (UAS) or boat-mounted plastic sphere dispensers are used.
Other uses Potassium permanganate is one of the principal chemicals used in the film and television industries to "age" props and set dressings. Its ready conversion to brown creates "hundred-year-old" or "ancient" looks on hessian cloth (burlap), ropes, timber and glass.
Potassium permanganate is used as an oxidizing agent in the synthesis of cocaine and methcathinone. It can purify cocaine paste with oxidization to increase its stability. This led to the Drug Enforcement Administration launching Operation Purple in 2000, with the goal of monitoring the world supply of potassium permanganate; however, potassium permanganate derivatives and substitutes were soon used thereafter to avoid the operation.
History