![]() ![]() ![]() In the “+4” state, manganese forms black manganese dioxide (MnO 2), which is the only compound of manganese (IV). The oxides formed in the “+2” and “+3” states (manganous oxide (MnO) and manganic oxide (Mn 2O 3), respectively) are bases due to their solubility in acid solutions, as shown in the following example: The manganic ion (Mn 3+) tends to be unstable in aqueous solution and disproportionates into Mn(II) and Mn(IV), as shown in the following reaction:ĢMn 3+(aq) + 2H 2O(l) → Mn 2+(aq) + MnO 2(s) + 4H +(aq)ĭisproportionation means that an element initially in only one oxidation state changes to two products: one product exhibiting a lower oxidation state and the other exhibiting a higher state. Examples of manganese in these states are illus- trated in the following series: Mn «0» Mn 2+ «+2» Mn 3+ «+3» MnO 2 «+4» MnO 3 – «+5» MnO 4 2-«+6» MnO 4 – «+7».Īs it is in group VIIA, its “+7” oxidation state is the preferred one. In compounds, manganese can be in any of the oxidation states from “+2” to “+7,” inclusive. For example, in hydrochloric acid, the following reaction takes place: Manganese metal is readily oxidized in the presence of oxygen gas, water, and hydrochloric acid. Manganese is an essential element in animals: it increases bone strength, helps absorb vitamin B1 and is an important cofactor for enzymes. Manganese is also a component of certain enzymes, and it is also used in the production of fertilizers and other chemicals, and in the manufacturing of ceramics and glass. In prehistoric times, manganese dioxide, MnO 2, was crushed to make the dark colors used in cave paintings. Manganese compounds are also added to gasoline and are used to clean impurities from glass to lighten it or give it a purple color. Certain dry cell batteries carry a mixture containing manganese oxide. Applications of manganese include its use in strengthening steel, which is used in the manufacture of railroad tracks and tank armor. The human body needs a small amount of manganese, which we can obtain from mussels, nuts, oats and pineapples. This element is present in seawater in the form of manganese hydroxide and manganese oxide, which have accumulated in layers over millions of years to form masses on the seabed. Pure manganese is dense, hard and brittle. The pure form of the metal is obtained mainly from the pyrolusite mineral, through a process called electrolysis. Manganese, like magnesium, is named after the Greek region of Magnesia, where there are many manganese ores, including the colorful rodochrosite mineral. Manganese is a chemical element with the symbol Mn and atomic number 25. ![]()
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