Potassium permanganate

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Dark purple, odorless crystals with a blue metallic sheen in reflected light. Potassium permanganate is a strong oxidizing agent that has been, in the past, used to bleach resins, waxes, fats, oils, Straw, Cotton, Silk, and other fibers. Excess bleaching of wood and paper results in dark brown stains caused by the precipitation of Manganese dioxide. It is now rarely used, if at all, as a bleach. Potassium permanganate is used to tan leathers and as a hypo eliminator in photographic processing solutions.

Synonyms and Related Terms

permanganic acid potassium salt; chameleon mineral; Condy's crystals


  • Strong oxidizing agent.
  • Reacts violently with organics and reducing salts.
  • Ingestion is toxic.
  • Contact and inhalation cause severe irritation.
  • ThermoFisher: SDS

Physical and Chemical Properties

Soluble in water, acetone, methanol. Decomposed by ethanol and other organic solvents.

Composition KMnO4
CAS 7722-64-7
Melting Point 240 C (dec)
Density 2.7032 g/ml
Molecular Weight mol. wt. = 158.03

Resources and Citations

  • Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
  • Hermann Kuhn, Conservation and Restoration of Works of Art and Antiquities, Butterworths, London, 1986
  • Michael McCann, Artist Beware, Watson-Guptill Publications, New York City, 1979
  • Book and Paper Group, Paper Conservation Catalog, AIC, 1984, 1989
  • The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 7824
  • A Glossary of Paper Conservation Terms, Margaret Ellis (ed.), Conservation Center of the Institute of Fine Arts, New York City, 1998