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Manganese(II,III) oxide is the chemical compound with formula Mn 3 O 4. Manganese is present in two oxidation states +2 and +3 and the formula is sometimes written as MnO · Mn 2 O 3 . Mn 3 O 4 is found in nature as the mineral hausmannite .
A particularly common oxidation state for manganese in aqueous solution is +2, which has a pale pink color. Many manganese(II) compounds are known, such as the aquo complexes derived from manganese(II) sulfate (MnSO 4) and manganese(II) chloride (MnCl 2). This oxidation state is also seen in the mineral rhodochrosite (manganese(II) carbonate ...
[5] γ-Mn 2 O 3 can be produced by oxidation followed by dehydration of manganese(II) hydroxide. [5] Many preparations of nano-crystalline Mn 2 O 3 have been reported, for example syntheses involving oxidation of Mn II salts or reduction of MnO 2. [6] [7] [8] Manganese(III) oxide is formed by the redox reaction in an alkaline cell:
For example, Cu compounds with Cu oxidation state +2 are called cupric and those with state +1 are cuprous. [4]: 172 The oxidation numbers of elements allow predictions of chemical formula and reactions, especially oxidation-reduction reactions. The oxidation numbers of the most stable chemical compounds follow trends in the periodic table.
Photons trapped by photosystem II move the system from state S 0 to S 1 to S 2 to S 3 and finally to S 4. S 4 reacts with water producing free oxygen: 2 H 2 O → O 2 + 4 H + + 4 e −. This conversion resets the catalyst to the S 0 state. The active site of the OEC consists of a cluster of manganese and calcium with the formula Mn 4 Ca 1 O x ...
Manganese oxide is any of a variety of manganese oxides and hydroxides. [1] These include Manganese(II) oxide, MnO; Manganese(II,III) oxide, Mn 3 O 4; Manganese(III) oxide, Mn 2 O 3; Manganese dioxide, MnO 2; Manganese(VI) oxide, MnO 3; Manganese(VII) oxide, Mn 2 O 7; Other manganese oxides include Mn 5 O 8, Mn 7 O 12 and Mn 7 O 13.
Manganese can form compounds in the +2, +3 and +4 oxidation states. The manganese(II) compounds are often light pink solids. Like some other metal difluorides, MnF 2 crystallizes in the rutile structure, which features octahedral Mn centers. [29] and it is used in the manufacture of special kinds of glass and lasers. [30]
For example, addition of potassium permanganate to an aqueous solution of sugar and sodium hydroxide produces the chemical chameleon reaction, which involves dramatic color changes associated with the various oxidation states of manganese. A related vigorous reaction is exploited as a fire starter in survival kits.