Manganese compounds Mn

In Table II are assembled the compounds for which measurements have been made (so far by the Gouy method) and the results obtained. The behavior of the manganese compound, Mn (05115)2, is especially interesting. This compound has been investigated over the temperature range 4-530°K. (116, 216), and is found to be antiferromagnetic with a Neel temperature of 134 2°K. Earlier results are thereby superseded. 

Ground-state electronic configuration is ls 2s 2p 3s 3p 3i 4s. Manganese compounds are known to exist in oxidation states ranging from —3 to +7 (Table 2). Both the lower and higher oxidation states are stabilized by complex formation. In its lower valence, manganese resembles its first row neighbors chromium and especially iron ia the Periodic Table. Commercially the most important valances are Mn, Mn ", or Mn ". ... 

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. 

The purple permanganate ion [14333-13-2], MnOu can be obtained from lower valent manganese compounds by a wide variety of reactions, eg, from manganese metal by anodic oxidation from Mn(II) solution by oxidants such as o2one, periodate, bismuthate, and persulfate (using Ag" as catalyst), lead peroxide in acid, or chlorine in base or from MnO by disproportionation, or chemical or electrochemical oxidation. 

Human and animal studies indicate that inorganic manganese compounds have a very low acute toxicity by any route of exposure. The toxicity values for a given Mn compound are shown in Table 20 to depend on the species of test animal as well as the route of exposure. Manganese concentrations as high as 2000 ppm were found to be tolerated by test animals over a six-month period without any ill effects (208). 

Table I. Boron-Manganese Compounds of the Type R2BMn(CO)4L and RB[Mn(CO)4L]2...

Mn-dependent peroxidase differs from lignin peroxidase in that it utilizes Mn (II) as the main substrate (74). The oxidized manganese ion, Mn (III), carries out the oxidation of organic molecules. Compound I of Mn-dependent peroxidase is able to oxidize Mn (II) to Mn (III) as well as some phenolic compounds the compound II can only oxidize Mn (II) (14) ... 

Fio. 6. Spectra of variety of manganese compounds MnF4 has high amplitude, MnS low amplitude fine structure. 

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... 

Calcination of a-FeOOH with small quantities of manganese compounds gives homogeneous brown pigments with the composition (Fe, Mn)203 [3.14], Calcination of iron and chromium compounds that decompose at elevated temperatures yields corresponding pigments with the composition (Fe, Cr)203 [3.15]. 

Lichtenberger et al. (209) have reported the He(I) photoelectron spectrum of the manganese compound (ju.-CH2)[(i75-C5H4CH3)Mn(CO)2]2 (3b) in the ionization energy range below 11 eV and have compared the results... 

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