Magnetic properties hydrides

Nuclear relaxation rates, iron-sulfur proteins, 47 267-268 Nuclear resonance boron hydrides and, 1 131-138 fluorescence, 6 438-445 Nuclear spin levels, 13 140-145 Magnetic properties of nuclei, 13 141-145 Nuclear testing... 

The investigations of magnetic properties of hydrides Er2Fei4BHx, that have been carried out previously have not taken into account the hydrogen loss in the sample with temperature increase. We have used an apparatus that has allowed to measure the magnetic properties of the sample at high temperatures in hydrogen atmosphere with pressure control. 

Apostolov, A., Bezdushnyi, R., Damianova, R., Stanev, N., Naumova, I., Gamari-Seale, H. (1994) Magnetic properties of some TbFenTiFlx hydrides, Phys.Stat.Sol.(a) 143, 385-390. 

Metallic hydrides are usually nonstoichiometric compounds, as expected from their relatively low heats of formation and the mobility of hydrogen. They are ordinarily described, chemically, in terms of any of three models in which hydrogen is considered a small interstitial atom, a proton, or a hydride anion. These models are discussed critically with particular reference to the group V metal hydrides. The interstitial atom model is shown to be useful crystallographically, the protonic model is questioned, and the hydridic model is shown to be the most useful at present. The effect of hydrogen content on the lattice parameter of VHn and the structural and magnetic properties of several hydrides are discussed in terms of these models. 

The range of experimental methods employed has not so far been very wide further work on the spectroscopic, thermochemical, and magnetic properties and on the kinetics of the formation and substitution reactions can be expected to be illuminating. Most work has been done on the trimeric chloride, the lowest stable member of the series, and the most abundant. As in the boron hydride series, significant advances are likely to result from investigations of the higher polymers. 

Magnetic properties of Zt(T1 xCtx)4 and compounds with hydrogen (Jacob et al. 1980), T = Fe, Co. Properties of hydrided ZrMn2 compounds are also given. 

In contrast to binary hydrides, relatively little is known of the structural and magnetic properties of hydrides of An-based intermetallic compounds. 

Altliough activated adsorjition does not necessarily precede catalysis, the investigation of the activated adsorption as well as the investigation of adsorption by means of IR spectra and of magnetic properties of chemisorbed molecules, must be important for catalysis. Of no less importance is the study of bulk chemical compounds which are similar to the supposed surface compounds, for example, the alcoholates in the dehydration of alcohols. From this point of view, one should study the properties of nitrides, carbides, hydrides, and other similar compounds. These studies are necessary because they permit one to make a judgment of the chemical forces which are displayed under conditions similar to catalysis. It should be borne in mind, however, that this evidence is indirect, as it refers not to the catalytically active centers themselves but to the surface, which is much larger they refer not to the activated complex, but to more stable compounds formed with the help of a catalyst. 

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