While the manganates are bright green, the permanganates, which are analogous to the per-chlorates, are almost black ; they dissolve in water with a deep purple colour ; the best known is the potassium salt, a solution of which is sold under the name of " Condy's Fluid." It is also a useful oxidising agent. If an oxidisable body is boiled with its solution, it loses oxygen, thus : ₂KMnO₄.Aq + ₃H₂O = ₂KOH.Aq + ₂MnO(OH)₂ + 3O ; if an acid, such as sulphuric acid, is present, the equation is: 2KMnO₄.Aq + 3H₂SO₄.Aq = K₂SO₄.Aq + ₂MnSO₄.Aq + 5O + 3H₂O.

Ferrates are also known; they are still more unstable than manganates.