Activity multi-site mixing

In carrying out calculations for multi-site mixing such as this, you can either use equation (15.10) directly, or work through the problem stepwise and ion by ion as with (15.8) the two methods are equivalent. Further details are given by Powell (1977). It is possible using analytic techniques such as X-ray diffraction, Mossbauer spectroscopy and infra-red, Raman and UV-visible spectroscopy to analyze for the concentration of different ions on specific crystal sites. Thus the activities, configurational entropies, and other such properties of solid solutions can often be calculated. This provides detailed information on the stability and structure of crystalline solutions. 

During the early researching stages of melting-iron catalyst, the concept of multi-component mixed catalyst proposed by Mittasch, the BET equation and the selective chemisorption method for determining active site on catalyst proposed by Emmett et al, proposed the iron catalyst as a prototypical model catalyst established on the basis of N2 adsorption on iron catalyst. Brill has proved that Fe (111) face first adsorbs N2, and found that the transformation of small distorted manifests... 

Langmuirian view, the active catalytic surface is comprised of a uniform distribution of static sites that do not interact with one another. This is sharply contrasted by the Taylor view, which proposes vacancies and topologically unique surface atom configurations as the centers of reactivity. The Langmuirian idea of a catalytically reactive surface leads to the ensemble effect that ascribes the changes in the selectivity for an alloy surface to the dilution of multi-atom surface ensembles in the alloy induced by mixing inert components into the active surface. In this view, the selectivity of a particular reaction depends predominantly on the number of reactive surface atoms that participate in elementary reaction events. 

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