Natural charging charge compensation

The different oxide stacking sequences in j8 and j8". Fig. 2.9, and in particular, the presence of mirror symmetry in the conduction plane of j8 but not P", lead to differences in detail in the nature of the sites for Na" ions in the conduction plane. Such differences together with the different charge compensation mechanisms cause the electrical properties of p and P" to differ somewhat, and in particular lead to rather different conduction mechanisms. 

Early work by Boyd et al. (1947), performed on zeohtes, showed that the ion exchange process is diffusion controlled and the reaction rate is limited by mass transfer phenomena that are either film-diffusion (ED) or particle-diffusion (PD) dependent. Under natural conditions, the charge compensation cations are held on a representative subsurface solid phase as follows within crystals in interlayer... 

For the compounds with lighter aUcali metals which have the same composition, the formation of the isoelectronic one-dimensionaUy extended chains is favored [96]. This once again demonstrates the effect of cation size beyond the charge compensating function on the nature of the observed anions. 

Neodymium in natural and artificial apatite is characterized by anomalous distribution of luminescence intensity in the groups at 1.06 and 1.3 pm. In each of these spectral groups there is one fine whose intensity exceeds many times the intensity of the remaining fines of said group (Morozov et al. 1970). In laser-induced luminescence of natural apatites we also found somewhat different luminescence spectra (Eig. 4.3). Decay times of these fines are rather close and it is possible to suppose that all Nd occupy the Ca(I) sites with different charge compensations. 

For the TOF SIMS analysis, only slides treated with a natural pH HAPS solution were used. These were subsequently extracted with warm and hot water. They were mounted into a grid sample holder for transportation into a VG IX23S time-of-flight (TOF) SIMS instrument operating at a vacuum of < 10 Torr with a microfocused liquid Ga metal ion primary beam source (30 keVx 1.0 nA). For charge compensation, an electron flood gun was used. The working resolution of the spectrometer was determined from a lead phthalocyanine spectrum for Pb+ at mlz = 208 and the molecular ion at mlz = 720, it was 500 and 1000, respectively. 

The chemical transformation of Ru-complexes in faujasite-type zeolites in the presence of water and of carbon monoxide-water mixtures is reviewed and further investigated by IR, UV-VIS spectroscopic and volumetric techniques. The catalytic activity of these materials in the watergasshift reaction was followed in a parallel way. The major observations could be rationalized in terms of a catalytic cycle involving Ru(I)bis and triscarbonyl intermediates stabilized in the supercages of the faujasite-type zeolite. The turnover frequency of this cycle is found to be determined by the nature, number and position of the charge compensating cations, as well as by the nature of the ligands present in the Ru-coordination sphere. 

In view of what precedes, it has been the aim of the present work to identify the Ru-species present in faujasite-type zeolites activated under WGS-conditions, making use of the avail-albe literature data. The activation procedure of Ru(III)hex-ammine in NaY has been related to its catalytic performance as low temperature WGS-catalvst. Subsequently, the basicity of the material was related to its catalytic behavior in the same reaction, by changing the nature of the parent complex, of the charge compensating cations and of the aluminum content of the faujasite-type zeolite. 

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