and water treatment additive in aquaculture. Manganates(VII) are not very stable thermally. For instance, potassium permanganate decomposes at 230 °C to potassium manganate and manganese dioxide, releasing oxygen gas: 2 KMnO4 → K2MnO4 + MnO2 + O2 A permanganate can oxidize an amine to a nitro compound, an alcohol to a ketone, an aldehyde to a carboxylic acid, a terminal alkene to a carboxylic acid, oxalic acid to carbon dioxide, and an alkene to a diol. This list is not exhaustive. In alkene oxidations one intermediate is a cyclic Mn(V) species: Compounds Ammonium permanganate, NH4MnO4 Barium permanganate, Ba(MnO4)2 Calcium permanganate, Ca(MnO4)2 Potassium permanganate, KMnO4 Sodium permanganate, NaMnO4 Silver permanganate, AgMnO4 See also Perchlorate, a similar ion with a chlorine(VII) center Permanganate index Chromate, which is isoelectronic with permanganate Pertechnetate References Oxometallates