Molar enthalpies, transition metal

A proper description of electronic defects in terms of simple point defect chemistry is even more complicated as the d electrons of the transition metals and their compounds are intermediate between localized and delocalized behaviour. Recent analysis of the redox thermodynamics of Lao.8Sro,2Co03. based upon data from coulometric titration measurements supports itinerant behaviour of the electronic charge carriers in this compound [172]. The analysis was based on the partial molar enthalpy and entropy of the oxygen incorporation reaction, which can be evaluated from changes in emf with temperature at different oxygen (non-)stoichiometries. The experimental value of the partial molar entropy (free formation entropy) of oxygen incorporation, Asq, could be... 

A typical example of the FIAT method applied to the determination of differential enthalpies of adsorption is illustrated in Figure 8 for adsorption of potassium chloroplatinate on a graphitised carbon black. The first injection of 0.2 pmol of K2PtCl6 produced a molar heat of adsorption of 128 kJmoland the fourth injection yielded 31 kJmol k The individual adsorptions occur on surface sites of different activity and reflect the heterogeneity of the surface. On the other hand, similar adsorption experiments on alumina produced relatively low heats of adsorptions emphasising the high affinity for transition metal salts of the polar sites present in graphitised carbons. 

Thermodynamic Data on Alloys , by Kubaschewski and Catterall, critically surveys data on some 400 binary and ternary metallic systems, with the term alloy interpreted to include transition-metal oxides, sulphides, carbides, nitrides, and phosphides. When available, values are given for the integral enthalpy and entropy of formation of the alloy, the relative partial molar enthalpy and entropy of one component, and the volume change on mixing. 

Pasturel et al. (1983) have introduced another simple model, one which casts the partial enthalpy of mixing at infinite R dilution, AH, in terms of the change in (, the Fermi energy, and the change in volume, with alloying. This model addresses liquid alloys of R s with non-transition metals. These authors find that their measured and calculated values of AH", for the lanthanide series of R s in liquid Al, agree rather well, and, moreover, that both show the same dependence on atomic number as does the molar volume. 

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