Manganese induce a strong green color in glass by forming less-colored iron(III) and slightly pink manganese(II), compensating for the residual color of the iron(III). Larger quantities of manganese are used to produce pink colored glass. Tetravalent manganese is used as an activator in red-emitting phosphors. While many compounds are known which show luminescence the majority is not used in commercial application due to low efficiency or deep red emission. However, several Mn aktivated fluorides were reported as potential red emitting phorshors for warm-white LEDs. But to this day, only KSiF:Mn is commercially available for use in warm-white LEDs. The manganese oxide
Manganese(II) sulfate highly characteristic. Typically, manganese ores are purified by their conversion to manganese(II) sulfate. Treatment of aqueous solutions of the sulfate with sodium carbonate leads to precipitation of manganese carbonate, which can be calcined to give the oxides MnO. In the laboratory, manganese sulfate can be made by treating manganese dioxide with sulfur dioxide: It can also be made by mixing potassium permanganate with sodium bisulfate and hydrogen peroxide. Manganese sulfate is a by-product of various industrially significant oxidations that use manganese dioxide, including the manufacture of hydroquinone and anisaldehyde. Electrolysis of manganese sulfate yields manganese dioxide, which is called EMD