Oxides magnetic measurements

Lithium oxides of Pu, magnetic measurements and reciprocal molar susceptibility vs. 

Rare-earth ions inserted in the tetraborides have the 34- oxidation state, except for CeB4 and YbB4 (see Fig. 2). The abnormal volume contraction for the CeB4 unit cell can be explained by the presence of some Ce ions . Recoilless y-ray emission spectra and magnetic measurements indicate that ytterbium in YbB4 has an intermediate valence state as in YbAl3... 

Before studying the reactivity of the nanoparticles, it is necessary to evaluate whether the synthetic method employed would lead to particles of clean unoxidized surface, able to react with incoming molecules. For this purpose we used, besides physical techniques (which are sometimes difficult to handle due to the high oxidability of particles prepared in this way), molecular methods, namely IR and NMR spectroscopy, as well as magnetic measurements which can give a precise description of the surface properties of the particles. 

Properties of FeCr,o solid samples have been studied by X-ray diffraction, 57Fe Mossbauer spectroscopy and magnetic measurements to stimulate the interaction of Fe with fullerene. FeCr,o samples have been prepared by decomposition of the 1,3-dipolar cycloadduct of the fullerene and ferrocene nitrile oxide. The components exhibit super paramagnetic properties originating from an interaction between FeCr,o complexes within the nano-particles. Each nano-particle consists of hundreds to thousands complexes (546). 

IR spectra, 27 283, 284 magnetic measurements, 27 280 oxidized state, 27 289 Raman spectra, 27 284 reduced state, 27 291 reflectance spectroscopy, 27 279 X-ray diffraction, 27 272, 273 support interactions, 27 290 Cobalt monoxide, field effect, 27 44, 45 Cobalt(nickel)-molybdenum-sulfide catalysts, 42 417... 

It should be pointed out that the treatment of phosphorus or sulfur donors bearing ferrocenyl groups with diiodine results in the formation of molecular charge-transfer adducts without simultaneous oxidation of the ferrocenyl groups (Durfey et al. 2000, Gridunova et al. 1982). At the same time, the reaction of 4-ferrocenyl-l,3-dithiolene-2-thione with diiodine leads to a charge-transfer complex in which the iron has been oxidized from Fe" to Fe ". This was confirmed by magnetic measurements and Moessbauer spectroscopy (Allen et al. 2003). 

MeOpyNO. 4-ClpyNO, or 4-N02pyN0) and [FeL ](C104)2 (L = 4-picoline. V-oxide. 4-MeOpyNO, 4-ClpyNO, 4-N02pyN0, 4-CNpyNO, or 3-CNpyNO) have been prepared, and have been characterized by magnetic measurements and i.r. and electronic spectroscopy. ... 

Tetranuclear manganese(III) carboxylate complexes have three different configurations for their metal centers fused open cubane, planar, or butterfly (see Figure 22). There is only one example of the first type namely [Mn4Q2(OAc)2(BSP)2] (105). The Mn Mn separations in (105) vary between 2.875(1)A and 3.122(1)A. Variable temperature magnetic measurements for (105) indicated weak antiferromagnetic interactions (/=—10.0cm and / = —3.7cm ) between the manganese(III) centers. Cyclic voltammetry of (105) in methanol shows one quasireversible oxidation wave at 0.01 V and two quasireversible reduction waves at about —0.4 V and —0.7 V vs. SCE. 

In addition to X-ray and neutron-diffraction structural characterization, the physical properties of iron oxides have been studied by a wide variety of techniques. Most common are conventional transport, optical, dielectric, calorimetric and magnetic measurements. In addition, NMR and Mossbauer are widely used. 

Solid-state sulfide compounds MMo2S4 (M = V, Cr, Fe, Co) contain infinite chains of Mo4S6 clusters with intracluster Mo-Mo distances (2.756-2.989 A) and intercluster distance (2.960 A) for the cobalt derivative (112). As the valence of M is +2, judging from magnetic measurements, and the average oxidation state of molybdenum +3, the CVE for M2Mo4S8 is 12. This agrees with five intracluster and one intercluster... 

The tetraamide [U Fc(NSiBu Me2)2 2] was prepared from the potassium salt of 1,1 -ferrocenylenediamine Fc N(H)SiBu Me2 2 and Ufdthf). Its oxidation by I2 followed by treatment with NaBPh4 produced the mixed-valence (Fe /Fe ") compound [U Fc-(. SiBLi. le2)2 f2l[BPh ], in which the centre mediates the electronic communication. The model of electron transfer between Fe and I- e " via a direct U-Fe interaction was confirmed by magnetic measurements, EPR, NIR and IR spectroscopy and DFT calculations on model systems. ... 

NiO(200) presents a small excess of oxygen, whereas NiO(250) contains metallic nickel (Table I). Magnetic measurements (15) have confirmed the chemical analysis (19). However, both oxides are p-type semiconductors, as shown by the Seebeck effect measurements. In the case of NiO(250), this result means that, although there is a total excess of nickel, the oxide phase still contains a small excess of oxygen (13). The electrical properties of both oxides are identical. 

In this study we present the first in-situ formation of a ternary transition metal oxide within the pores of MCM-48 silica. XRD measurements showed the preservation of the host structure as well as the formation of 5-6 nm small particles. In addition, the analysis of nitrogen physisorption data revealed the existence of mesopores with smaller pore diameters and surface areas in comparison to the pristine phase, which can be attributed to the introduction of the Co/Fe/O phase into the pores. First qualitative XANES and EXAFS analyses support the formation of CoFe204 nanoparticles. TEM investigations on particle size and structure are in progress. To learn more about the properties of the oxide nanoparticles Mossbauer and magnetic measurements have to be carried out, which are planned for the future. 

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