A permanganate is the general name for a chemical compound containing the manganate(VII) ion, (MnO4−). Because manganese is in the +7 oxidation state, the permanganate(VII) ion is a strong oxidizing agent. The ion has tetrahedral geometry. Permanganate solutions are purple in color and are stable in neutral or slightly alkaline media.The exact chemical reaction is dependent upon the organic contaminants present and the oxidant utilized. For example, trichloroethene (C2HCl3) is oxidized by sodium permanganate to form carbon dioxide (CO2), manganese dioxide (MnO2), sodium ions (Na+), hydronium ions (H+), and chloride ions (Cl-)
In an acidic solution, permanganate(VII) is reduced to the colourless +2 oxidation state of the manganese(II) (Mn2+) ion.
8 H+ + MnO4− + 5 e− → Mn2+ + 4 H2O
In a strongly basic solution, permanganate(VII) is reduced to the green +6 oxidation state of the manganate ion, MnO42−.
MnO4− + e− → MnO42−
In a neutral medium however, it gets reduced to the brown +4 oxidation state of manganese dioxide MnO2.
^Cotton, F. Albert; Wilkinson, Geoffrey; Carlos A. Murillo and Manfred Bochmann (1999). Advanced Inorganic Chemistry (6th ed.). New York: John Wiley & Sons, Inc. p. 770. ISBN978-0471199571.Cite uses deprecated parameters (help)