Manganese spectra

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). 

Figure 2. Alpha spectrum for a radium adsorbing manganese-oxide thin film exposed to a groundwater sample, after Surbeck (2000) and Eikenberg et al. (2001b). A 2x2 cm sheet is exposed to O.l-l.O L of sample for 2 days, capturing nearly all of the radium in the sample. These sample discs can be used directly for low-level alpha spectrometry without the need for further separation and preparation methods to produce planar sample sources. Energy resolution is nearly as good as for electroplated sources, and detection limits are typically 0.2 mBqA (6 fg Ra/L) for Ra and " Ra for a one-week counting period. These sensitivities are comparable to traditional methods of alpha spectrometry. [Used by permission of Elsevier Science, from Eikenberg et al. (2001), J Environ Radioact, Vol. 54, Fig. 4, p. 117]...

The spectrum of the low-spin manganese(n) complex, [Mn(dppe)2(CO)(CN-Bu)]2+, (dppe = Ph2PCH2CH2PPh2), in a CH2C12/THF glass is shown in Figure 4.4(a).24 The spin Hamiltonian parameters, obtained from least-squares... 

The low-spin manganese(n) complex [Mn(dppe)2-(CO)(CNBu)]2+ gave us a textbook example of a well-behaved ESR spectrum characterized by coincident g- and hyperfine-matrix principal axes. The nearly identical complex [Mn(dppm)2(CO)(CN)]+, (dppm = Ph2PCH2PPh2) (ref. 25) provides us with a good example of non-coincident principal axes. The frozen solution spectrum (Figure 4.8) shows that the parallel features are not evenly spaced. 

Group VIIA (Mn, Tc. Re). A number of mononuclear manganese carbonyl derivatives have been y- irradiated and examined by e.s.r. spectroscopy. The motivation behind much of this effort was the search for the elusive radical Mn(CO)s. The e.s.r. spectrum of this species is now firmly (35-37) established (Figure 4), although there is still some suggestion that the true "naked Mn(CO)s has yet to be observed (37). 

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. 

However, in the sodium atom, An = 0 is also allowed. Thus the 3s —> 3p transition is allowed, although the 3s —> 4s is forbidden, since in this case A/ = 0 and is forbidden. Taken together, the Bohr model of quantized electron orbitals, the selection rules, and the relationship between wavelength and energy derived from particle-wave duality are sufficient to explain the major features of the emission spectra of all elements. For the heavier elements in the periodic table, the absorption and emission spectra can be extremely complicated - manganese and iron, for example, have about 4600 lines in the visible and UV region of the spectrum. 

With XPS it is possible to obtain good analytical information on the amount of metal adsorbed and, in favourable cases, to identify the chemical form of that metal. Oxidation states are readily determined and it can be shown, for example, that adsorption of Co(II) on manganese oxides results in oxidation to Co(III) (38,39), whereas adsorption of Co(II) on zirconia and alumina leads to the formation of cobalt(II) hydroxide (40). With Y-type zeolites hexaaquacobalt(II) is adsorbed as Co(II), and cobalt(III) hexaammlne is adsorbed as Co(III). The XPS spectrum of Co(II) adsorbed on chlorite was consistent with the presence of the hexaaquacobalt(II) ion for pH 3-7 and indicated that no cobalt(II) hydroxide was present (41). With kaollnlte and llllte, Co is adsorbed as Co(II) over the pH range 3-10 (39,42), it being bound as the aqua ion below pH 6 and as the hydroxide above pH 8. Measurements involving Pb have... 

The optical emission spectrum of technetium is uniquely characteristic of the element " with a few strong lines relatively widely spaced as in the spectra of manganese, molybdenum and rhenium. Twenty-five lines are observed in the arc and spark spectra between 2200 and 9000 A. Many of these lines are free from ruthenium or rhenium interferences and are therefore useful analytically. Using the resonance lines of Tc-I at 4297.06, 4262.26, 4238.19, and 4031.63 A as little as 0.1 ng of technetium can be reliably determined. 

The oxides of manganese give spectra, shown in Fig. 5, where the valence shift from +2 to higher (+3, +4) is the outstanding feature. The MnO spectrum shows extended structure probably related to the simple crys-... 

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

Fig. 7. Type 111 spectra of manganese in four metallic phases, MnSi phase has distinctive spectrum.

The simple hydrated ionic salt, chromic nitrate, has a spectrum quite distinct from the ionic salts of cobalt and manganese. The principal peak shows a splitting. This may be related to the very strong aflSnity which chromium displays toward its first coordination sphere of water. 

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