Magnetic susceptibility studies

Tofield BC (1975) The Study of Covalency by Magnetic Neutron Scattering. 21 1-87 Trautwein AX, Bill E, Bominaar EL, Winkler H (1991) Iron-Containing Proteins and Related Analogs-Complementary Mossbauer, EPR and Magnetic Susceptibility Studies. 78 1-96 Trautwein AX (1974) Mossbauer-Spectroscopy on Heme Proteins. 20 101-167 Tressaud A, Dance J-M (1982) Relationships Between Structure and Low-Dimensional Magnetism in Fluorides. 52 87-146... 

Table I. Samples Used for MOssbauer Spectroscopy and Magnetic Susceptibility Studies...

Trautwein AX, Bill E, Bominaar EL, Winkler H. 1991. Iron-containing proteins and related analogs. Complementary Mossbauer, EPR and magnetic susceptibility studies. Struct Bonding (Berlin) 78 1-95. 

Magnetic susceptibility studies can be difficult to interpret for multicentered metalloproteins particularly when paramagnetic impurities are present, whereas with MCD spectroscopy the magnetic properties of individual centers can be investigated independently. However, it should be emphasized that MCD studies... 

The structures of the anhydrous vanadiumfiii) sulphates, 2(804)3, yellow (monoclinic) and green (rhombohedral), have been investigated, and a new double sulphate, (NH4)3V(S04)3, has been prepared and extensively characterized. Single-crystal magnetic susceptibility studies (1.5—20 K) of guanidi-nium vanadium(iii) sulphate have been reported, and the zero-field splitting has been estimated as 3.74 cm . ... 

It would seem that the carrier identification would be readily resolved by experiment. In fact, numerous experiments have found the carriers to be electrons in BaPb B Og (78)(79), the carrier concentration and Tc readily scaling with Bi content until a CDW decreases the carrier density. This interpretation is well supported by a magnetic susceptibility study (80). Even though the parent compound BaBiOg is a hole type semiconductor (81), the carrier type has been shown to be n or electronic in character (75) in Ba K BiOg. 

Reactions with Radicai ions of Like Charge. In the final section, we briefly mention reactions between radical ions of like charge. One of the longstanding problems of radical ion chemistry involves the actual stmcture of ketyls. Following extensive conductivity and magnetic susceptibility studies in the 1930s detailed ESR and optical studies have demonstrated the existence and interconversion of at least four distinct species a free ketyl anion a monomer ion pair a... 

Demazeau et al. (1982) reported that Ni is in the low-spin t g state in LaSrNi04, but in the high-spin tig e state in LaBaNi04. A magnetic susceptibility study of LaSr, Ba Ni04 has shown the eg electrons in this system to be always in extended states forming a band with increase in x, the band-width decreases, accom-... 

Results from magnetic susceptibility studies have been reported (50—53). Measurements (50) obtained by the Gouy method are shown in Figure 3. These are lower than those of other investigators. However, the temperature dependences of the magnetic susceptibilities, %, for the various plutonium allotropes were similar. a-Plutonium single crystals show a slight anisotropy of % (54). 

Molybdenum oxide - alumina systems have been studied in detail (4-8). Several authors have pointed out that a molybdate surface layer is formed, due to an interaction between molybdenum oxide and the alumina support (9-11). Richardson (12) studied the structural form of cobalt in several oxidic cobalt-molybdenum-alumina catalysts. The presence of an active cobalt-molybdate complex was concluded from magnetic susceptibility measurements. Moreover cobalt aluminate and cobalt oxide were found. Only the active cobalt molybdate complex would contribute to the activity and be characterized by octahedrally coordinated cobalt. Lipsch and Schuit (10) studied a commercial oxidic hydrodesulfurization catalyst, containing 12 wt% M0O3 and 4 wt% CoO. They concluded that a cobalt aluminate phase was present and could not find indications for an active cobalt molybdate complex. Recent magnetic susceptibility studies of the same type of catalyst (13) confirmed the conclusion of Lipsch and Schuit. 

A recent Mossbauer and magnetic susceptibility study on [Fe(phen)2ox] 5 H20 186) has identified this complex as a typical 5T2(0, ) 1Aj(Oh) spin crossover system rather than a complex with a spin triplet ground state. Moreover, it has been shown 186> that the magnetic properties are very susceptible to the amount of lattice water present Pumping off the lattice water gradually favours more and more the HS state the stable monohydrate, finally, turned out to be a paramagnet. 

The investigation here reported was carried out in an attempt to show that such surface states did exist and that sorption and magnetic susceptibility studies of hydrogen-palladium systems might answer some of the questions raised by previous investigators. 

X-ray structural studies of [Cu2(bpim)(im)]2(N03)4 4H20 establish the presence of imidazolate bridges in III, Figure 6. Solutions of this compound reversibly take up four protons between the end points at PH 9.75 and 4.25, consistent with Reaction 4. Magnetic susceptibility studies show that the copper (II) centers in III are antiferromagnetically... 

Comparative variable-temperature magnetic susceptibility studies have been undertaken for [MnCl(TPP)] and [MnCl(TPP)(py)]676,617 and accurate estimates ( — 2.3 and - 3.0cm 1 respectively) of the zero-field splitting of the ground state of Mn111 in these compounds obtained. As expected the magnetic moments of both compounds at room temperature are close to the spin-only value for S = 2. 

While the stoichiometries of the Mn SOD enzymes appear to vary, the properties of the Mn-binding site do not. This is borne out in the electronic spectra of these proteins, which display a great degree of similarity despite the diversity of sources from which they have been isolated (Table II). This type of spectrum is distinctive for manganese in the trivalent oxidation state (3). The native enzymes are EPR silent, as might be anticipated if they contained Mn solely as the trivalent ion (S = 2) (1, 6,12,18-20, 24). However, when the enzymes are denatured, the characteristic six-line pattern of Mn(II) (I = 5/2) appears. Magnetic susceptibility studies with the E. coli SOD were consistent with the presence of a monomeric Mn(III) complex with a zero-field splitting of 1 to 2 cm-1 (4). The enzymes are additionally metal specific (however, see Refs. 36 and 37) metal reconstitution studies with E. coli and B. stearothermophilus revealed a strict requirement for Mn for superoxide dismutase activity (2, 22, 23). 

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