Cobalt decreasing value

Decomposition rates of (Ni,Co) mellitates [1110] increase with increase in nickel content. The a—time curves for the pure components and the mixed mellitates were deceleratory throughout and there was no discontinuity in shape with changes in composition. Rates of decomposition of the solid solutions were appreciably greater than those expected from the decomposition of the individual components present (Fig. 19). The values of E determined for the initial stages of the decomposition of mixtures were close to that found for the nickel salt (184 kJ mole 1) and in the latter stages tended to increase towards that for cobalt mellitate (251 kJ mole-1). Values of A showed a systematic decrease with increase in cobalt content. 

It is indicated by the observed interatomic distances and shown by magnetic data that there occurs some deviation from this simple and attractive scheme in the middle region of the sequence. From chromium to cobalt the interatomic distances do not continue to decrease in value, as expected with increase in the number of bonds instead they remain nearly constant Cr, A2, 2.49A Mn, no simple structure Fe, A2, 2.48A, Al, 2.52A Co, Al, A3, 2.50-2.51A Ni,... 

In Fig. 1 there is indicated the division of the nine outer orbitals into these two classes. It is assumed that electrons occupying orbitals of the first class (weak interatomic interactions) in an atom tend to remain unpaired (Hund s rule of maximum multiplicity), and that electrons occupying orbitals of the second class pair with similar electrons of adjacent atoms. Let us call these orbitals atomic orbitals and bond orbitals, respectively. In copper all of the atomic orbitals are occupied by pairs. In nickel, with ou = 0.61, there are 0.61 unpaired electrons in atomic orbitals, and in cobalt 1.71. (The deviation from unity of the difference between the values for cobalt and nickel may be the result of experimental error in the cobalt value, which is uncertain because of the magnetic hardness of this element.) This indicates that the energy diagram of Fig. 1 does not change very much from metal to metal. Substantiation of this is provided by the values of cra for copper-nickel alloys,12 which decrease linearly with mole fraction of copper from mole fraction 0.6 of copper, and by the related values for zinc-nickel and other alloys.13 The value a a = 2.61 would accordingly be expected for iron, if there were 2.61 or more d orbitals in the atomic orbital class. We conclude from the observed value [Pg.347]

Using the tri-iodide/iodide redox couple and the sensitizers (22) and (56), several groups have reported up to 8-10% solar cell efficiency where the potential mismatch between the sensitizer and the redox couple is around 0.5 V vs. SCE. If one develops a suitable redox couple that decreases the potential difference between the sensitizer and the redox couple, then the cell efficiency could increase by 30%, i.e., from the present value of 10% up to 13%. Towards this goal, Oskam et al. have employed pseudohalogens in place of the triiodide/iodide redox couples, where the equilibrium potential is 0.43 V more positive than that of the iodide/iodide redox couple.17 Yamada and co-workers have used cobalt tris-phenanthroline complexes as electron relays (based on the CoII/m couple) in dye-sensitized solar cells.95... 

Van Steen11 and Schulz et al.24,25 have presented a detailed analysis of FT products obtained on iron and cobalt catalysts that revealed an exponential decrease of branching with increasing carbon number, as demonstrated in Figure 11.8. At elevated carbon numbers the fractions of branched hydrocarbons approach a constant value. 

The approximating polynomial was also used to obtain response surfaces. Figure 8.16 shows a 3D response surface and a 2D contour plot for the rate of deposition as a function of the concentration of cobalt sulfate and pH. The response surface in Figure 8.16 shows that the rate of deposition first increases, reaches a maximum, and then decreases with increase in pH. The value of this maximum increases with an increase in the concentration of cobalt sulfate. 

XPS has been used to characterize the three mixtures containing respectively 7,25, and 50 weight % of Bi2Mo30i2 (Table II samples J,K and L). These samples have been characterized before and after catalytic reaction (table III). Bi, Mo, Fe, Co and O have been analyzed. The Mo/0 ratio remains equal to 0.25 for all the samples, before and after catalysis which confirms that no new phase was formed since the molybdates suspected to have formed, have a much lower Mo/0 ratio (0.17 for Bi2Mo06 and Bi3FeMo20i2). Concerning the Bi/(Fe+Co) ratio, it can first be observed that before catalysis this ratio was always lower than that calculated from chemical analysis. This can be explained by the difference between the particles size of the bismuth molybdate and the iron and cobalt molybdates which is in a ratio of more than 30 as calculated from differences in surface area values, 0.3 and 9 to 22 m. g Secondly the Bi/(Fe+Co) ratio increased systematically after catalysis which could be explained by the decrease in size of the bismuth molybdate particles or by the covering of the iron and cobalt molybdate particles by the bismuth molybdate or by both effects. 

In all cases, the oxidation rate was smallest for experiments involving thiophenol and ferf-butanethiol. The oxygen uptake vs. time curves for cobalt-catalyzed reactions showed an initial high slope followed by a decrease in slope after ca. 30% reaction to a final steady value. 

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