Other Manganese Compounds

Other Manganese Compounds.—MnGa2Se and MnGa2Te have been prepared by direct synthesis from the elements at 900—1000 Structural studies on (Fe, 

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Figure 6 shows spectra of other manganese compounds. The spectrum of manganese 1,10-phenanthroline dichloride matches those of the divalent... 

CO release from a range of other manganese compounds has been reported but are generally slow CO releasers [204]. 

An additional problem is encountered when the isolated solid is non-stoichiometric. For example, precipitating Mn + as Mn(OH)2, followed by heating to produce the oxide, frequently produces a solid with a stoichiometry of MnO ) where x varies between 1 and 2. In this case the nonstoichiometric product results from the formation of a mixture of several oxides that differ in the oxidation state of manganese. Other nonstoichiometric compounds form as a result of lattice defects in the crystal structure. ... 

The brown crystalline manganese(III) acetate dihydrate is of considerable commercial importance because it is often used as the source material for other trivalent manganese compounds. It can be made by oxidation of manganese(II) acetate using chlorine or potassium permanganate, or by reaction of manganese(II) nitrate and acetic anhydride. 

The cake is leached with water in order to dissolve tantalum and niobium (and other related compounds) in the form of fluoride salts of ammonium. Ammonium fluoroferrate and fluoromanganate are unstable in aqueous solutions of low acidity. It is assumed that iron and manganese will form precipitates of insoluble fluorides or oxyfluorides that can be separated from the solution by filtration. 

One other important compound of manganese is potassium permanganate, KMnO . This is an intensely violet-colored material much used as an oxidizing agent in the laboratory. (It is too expensive to use on a large scale in industry, chlorine is more likely to be used.)... 

See other mercury compounds, n-s compounds 4343. Manganese tctralluoridc... 

Gas-diffusion flow injection analysis is capable of detecting very low concentrations of chlorine dioxide in water (i.e., detection limit is 5 ppb). A chemiluminescence flow-through detector cell is used to measure the concentration chlorine dioxide as a function of chemiluminescence intensity. A gas diffusion membrane separates the donor stream from the detecting stream and removes ionic interferences from iron and manganese compounds, as well as from other oxychlorinated compounds, such as chlorate and chlorite (Hollowell et al. 1986 Saksa and Smart 1985). 

Manganese(II) chloride forms adducts with ammonia, hydroxylamine and many other nitrogen compounds. Many adducts are stable at ordinary temperatures. Examples are MnCb BNHs and MnCE 2NH2OH. 

The dimensions of the unit cells do not seem to be related to each other, so that the compounds listed apparently are not iso-structural. In contrast to this Hoppe, Liebe and Ddhne (166) assume the manganese compounds AMnFs (A = K, Rb, Cs) to be of the same type. The x-ray diagrams are similar to each other, but stiU could not be indexed. It remains to be checked, whether the unit cell given later by Clark and Sadana (66) for KMnFs may be applicable to the Rb- and Cs-compounds. 

The findings of Bussemeier et al. and Kolbel and Tillmetz were, however, later on confirmed by the work of Barrault and co-workersand a maximum increase in light olefin production was found for bulk chemical composition Fe/Mn ratios of 1. This group also explained the promotion effects in terms of electronic changes in the metal atoms by the surrounding manganese compounds i.e., an electronic promotion effect. On the other hand, Barrault et al. also concluded that the beneficial effect of the promoter was related to the preparation method used, and more specifically to the formation of specific precursor compounds. Other preparation routes were... 

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