Manganese forms

Carbon reacts with molten manganese forming various carbides including [12266-65-8], Mn C [12121 -90-3], Mn C [12076-37-8], Mn2C2... 

The sulfides are fewer and less familiar than the oxides but, as is to be expected, favour lower oxidation states of the metals. Thus manganese forms MnS2 which has the pyrite structure (p. 680) with discrete Mn and 82 ions and is converted on heating to MnS and... 

Warden B.T., Reisenauer H.M. Fractionation of soil manganese forms important to plant availability. Soil Sci Soc Am J 1991 55 345-349. 

Manganese in soil has many characteristics that are similar to iron for instance, it exists in multiple oxidation states Mn2+, Mn3+, and Mn4+. Although manganese can exist in the laboratory in other oxidations states, from -3 to +7, the +2 to +4 species are the ones commonly found in soil. Manganese forms various oxide and hydroxide species and chelates with many soil components. Its low oxidation state (i.e., Mn2+) is more soluble and more available than its high oxidation state (i.e., Mn4+). 

Manganese forms a decacarbonyl Mn2(CO)10 in which each manganese has the required share in 18 electrons to achieve the noble gas configuration. Reduction of this covalent compound with sodium amalgam gives the salt Na[Mn(CO)5], sodium pentacarbonyl-manganate ( - 1) in the ion Mn(CO)5 the noble gas structure is again attained. 

Manganese forms manganesefll) halides when heated with halogens. With fluorine, reaction is very vigorous and the products are MnF2 and MnFs ... 

The ferric iron is then changed to ferrous iron and with the oxidized manganese forms a purple color. This is characteristic of bottles which have been subjected to the sun s rays for a period of time. The manganese is added initially to the glass as a decolorizer to offset the yellow color of the iron. (7 )... 

Manganese forms a large number of mononuclear complexes in oxidation states II, III, and IV with acyclic and other common ligands. The complexes primarily are six-coordinate species with octahedral or pseudo-octahedral geometries. Some exceptions to this categorization are the tetraoxo anions in oxidation states V, VI, and VII and the manganocenes. Table 1 contains electrochemical data for representative redox couples in which the Mn coordination environment remains invariant with oxidation state. Many entries are for homoleptic complexes, but some species with mixed... 

They form more complicated ions with high oxidation states. For example, chromium forms the dichromate(vi) ion, Cr2072-, which contains chromium with a +6 oxidation state (Cr(vi)) and manganese forms the manganate(vu) ion, Mn04, which contains manganese with a +7 oxidation state (Mn(vn)). 

The oxidation-reduction potentials and reaction constants of oxidation of iron and manganese differ and these reactions can occur in different amounts of oxygen. That is why the level of appearance of particulate manganese is situated higher than that of particulate iron [63]. Bacteria have been shown to oxidize manganese [64], whereas iron oxidation is possible without bacteria but can be carried out with bacteria [50]. Reduced iron can be oxidized by particulate manganese, forming complex compounds [65]. 

Manganese forms three oxides, MnO, Mn203, which is naturally occurring as the mineral hausmanite, and Mn02, which is also the composition of the mineral pyrolucite. The lowest oxide, MnO, can be obtained by the partial reduction of Mn02 with hydrogen as shown in the following equation ... 

Superoxide dismutase The major intracellular antioxidant enzyme in aerobic cells, the Cu-Zn form in the cytoplasm and the manganese form in the mitochondria, reduces superoxide radicals to hydrogen peroxide very rapidly and specifically. 

Inman first showed that trivalent manganese formed a complex with transferrins by adding hydrogen peroxide to a mixture of Mn2+ and the apoenzyme (118). Displacement studies revealed that the order of binding for both the human serum enzyme and ovotransferrin was Fe3+ > Mn3+ > Cu2+. The Mn complex displayed a distinctive visible band maximum at 429 nm. Further studies of the Mn-containing protein by... 

Manganese can be removed as Mn(OH)2 using a suitable OH source. Upon introduction of the hydroxide source, however, it is not only this solid that is produced. Manganese forms complex ions with the hydroxide. The complex equilibrium reactions are as follows (Snoeyink and Jenkins, 1980) ... 

Calcium as well as iron or manganese form molten chlorides at the reaction temperature, causing difficulties in reactor design. 

The role played by sand here is probably to catalyze the NaI04 oxidation of the low valent manganese formed back to permanganate and/or to prevent permanganate from further reduction beyond Mn(V) so that it could easily be oxidized by sodium metaperiodate to regenerate permanganate [53]. 

Iron and manganese form compounds which are isoinurplinns with K /I a TV and are therefore not removed by Marignac s method. ()nc met hud of separating these elements is to decompose the fluorides with concentrated IK-1, add I IK, iuu then NI Id when I he inanganese and iron are. precipitated. 

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