Manganese physical properties

Divalent manganese compounds are stable in acidic solutions but are readily oxidized under alkaline conditions. Most soluble forms of manganese that occur in nature are of the divalent state. Manganese(Il) compounds are characteristically pink to colorless, with the exception of MnO and MnS which are green, and Mn(OH)2, which is white. The physical properties of selected manganese(Il) compounds are given in Table 6. 

Steel is essentially iron with a small amount of carbon. Additional elements are present in small quantities. Contaminants such as sulfur and phosphorus are tolerated at varying levels, depending on the use to which the steel is to be put. Since they are present in the raw material from which the steel is made it is not economic to remove them. Alloying elements such as manganese, silicon, nickel, chromium, molybdenum and vanadium are present at specified levels to improve physical properties such as toughness or corrosion resistance. 

The /3-alloys are different in nature from the 7-alloys and the a-manganese and /3-manganese structures discussed above, in that they are not complex structures, but are simple, being based upon the body-centered arrangement. /3-Brass, for example, has either a disordered structure, above 480°K, the copper and zinc atoms in essentially equal number being distributed largely at random over the points of a body-centered cubic lattice, or an ordered structure, below 300°K, with copper and zinc at the positions 000 and, respectively, of the cubic unit. Moreover, the physical properties of /3-brass are not those that indicate a filled zone structure. 

Manganese borates, 4 282 Manganese boron, 4 136 Manganese bromide, physical properties of, 4 329... 

Manganese is a reactive metal that has several oxidation states (2, 3, 4, 6, and 7) that are responsible for its varied chemical compounds. The chemical and physical properties of manganese are similar to the properties of its companions in group 7—technetium ( jTc) and rhenium ( jRe). 

There are four allotropic forms of manganese, which means each of its allotropes has a different crystal form and molecular structure. Therefore, each allotrope exhibits different chemical and physical properties (see the forms of carbon—diamond, carbon black, and graphite). The alpha (a) allotrope is stable at room temperature whereas the gamma (y) form is soft, bendable, and easy to cut. The delta A allotrope exists only at temperatures above 1,100°C. As a pure metal, it cannot be worked into different shapes because it is too brittle. Manganese is responsible for the color in amethyst crystals and is used to make amethyst-colored glass. 

Table 4 Selected physical properties of mononuclear manganese(III) complexes.

Elemental composition K 24.74%, Mn 34.76%, 0 40.50%. The compound may be identified by its dark purple color and other physical properties, and confirmed by chemical analysis for the elements potassium and manganese by AA, ICP, and other instrumental means (see Potassium and Manganese). The concentration of permanganate ion, Mn04 in aqueous solution may be determined by titration with a standard solution of oxahc acid or ferrous ion (see Reactions). 

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