Manganese banding

Keywords Woodstock, Manganese, Banded Iron Formations, Plymouth Deposit. 

The zinc content of soil limonite was found to be always greater than that of the soil matrix in Tennessee subsurface soil samples (251), Burns and Fuerstenau (40) determined the occluded heavy metal concentrations in oceanic manganese nodules via an electron probe. They found that nickel and copper occurred in the high manganese bands while cobalt occurred predominantly in the iron rich areas. 

The aerobic and anaerobic degradation of acetone is initiated by carboxylation to acetoac-etate. The involvement of manganese has been examined in photoheterotrophically grown Rhodobacter capsulatus strain BIO and the presence of Mn verified from the X-band EPR spectrum (Boyd et al. 2004). 

By far the most important ores of iron come from Precambrian banded iron formations (BIF), which are essentially chemical sediments of alternating siliceous and iron-rich bands. The most notable occurrences are those at Hamersley in Australia, Lake Superior in USA and Canada, Transvaal in South Africa, and Bihar and Karnataka in India. The important manganese deposits of the world are associated with sedimentary deposits the manganese nodules on the ocean floor are also chemically precipitated from solutions. Phosphorites, the main source of phosphates, are special types of sedimentary deposits formed under marine conditions. Bedded iron sulfide deposits are formed by sulfate reducing bacteria in sedimentary environments. Similarly uranium-vanadium in sandstone-type uranium deposits and stratiform lead and zinc concentrations associated with carbonate rocks owe their origin to syngenetic chemical precipitation. 

Here, A is the nearly isotropic nuclear coupling constant, I is the nuclear spin (Iun = I), and m is the particular nuclear spin state. It may be observed that the zero field splitting term D has a second-order effect which must be considered at magnetic fields near 3,000 G (X-band). In addition to this complication nuclear transitions for which Am = 1 and 2 must also be considered. The analysis by Barry and Lay (171) of the Mn2+ spectrum in a CsX zeolite is shown in Fig. 35. From such spectra these authors have proposed that manganese is found in five different sites, depending upon the type of zeolite, the primary cation, and the extent of dehydration. 

FIGURE 5.12 Manganese as a common contaminant in protein EPR. This X-band spectrum is characteristic for high-spin Mn(II) aspecifically bound to proteins. 

In a study on another manganese enzyme, glutathione transferase, the Hoffmann group has proposed Q-band dispersion EPR at the unusually low temperature of 2 K as the optimal approach to collect data from Mn11 centers with D hv (Smoukov et al. 2002). This proposal would be practically limited by the fact that Q-band spectrometers running at 2 K can be counted on the fingers of one finger however, dispersion spectra are readily obtained in Q-band also at helium-flow temperatures (i.e., T>4.2K). 

Ferromanganese nodules found in freshwater lakes show concentric, alternating, iron- and manganese-rich bands radiating out from a central nucleus of detrital rock (e.g. Harriss Troup 1970). The nodules are found primarily in shallow (1-5 meters depth) regions of lakes, in regions with little to no finegrained sediment accumulation (e.g. Kindle 1935). 

Other cyclic olefine-manganese tricarbonyl complexes were investigated by Whitesides and Lichteriberger (64), and include (77schd)Mn(CO)3,0 sced)Mn(CO)3, and (i7scet)Mn(CO)3. In all three complexes, the ionizations of the six d-electrons fall at 8 eV, giving rise to a broad band, while 7r orbitals of the cyclic ligands produce two bands, at 8.5 and 10 eV. 

Nonradiative energy transfer is very often used in practical applications, such as to enhance the efficiency of phosphors and lasers. A nice example is the commercial phosphor Cas(P04)3 (FCl), which is doubly activated by Sb + and Mn + ions. When the phosphor is singly activated by Mn + ions, it turns out to be very inefficient, due to the weak absorption bands of the divalent manganese ion. However, coactivation with Sb + ions produces a very intense emission from the Mn + ions, because the Sb + ions (the donor centers) efficiently absorb the ultraviolet emission (253.6 nm) of... 

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