Mixing entropy, metallic liquids

The entropy contents of lead chalcogenides have been measured240 at temperatures between 300 K and their melting points. Enthalpies of mixing in the liquid state (for mole fractions of chalcogen = 0.5) were calculated. These values confirm the more metallic nature of the melts with tellurium as... 

Sorption of Cu(tfac)2 on a column depends on the amount of the compound injected, the content of the liquid phase in the bed, the nature of the support and temperature. Substantial sorption of Cu(tfac)2 by glass tubing and glass-wool plugs was observed. It was also shown that sorption of the copper chelate by the bed is partialy reversible . The retention data for Cr(dik)3, Co(dik)3 and Al(dik)3 complexes were measured at various temperatures and various flow rates. The results enable one to select conditions for the GC separation of Cr, Al and Co S-diketonates. Retention of tfac and hfac of various metals on various supports were also studied and were widely used for the determination of the metals. Both adsorption and partition coefficients were found to be functions of the average thickness of the film of the stationary phase . Specific retention volumes, adsorption isotherms, molar heats and entropy of solution were determined from the GC data . The retention of metal chelates on various stationary phases is mainly due to adsorption at the gas-liquid interface. However, the classical equation which describes the retention when mixed mechanisms occur is inappropriate to represent the behavior of such systems. This failure occurs because both adsorption and partition coefficients are functions of the average thickness of the film of the stationary phase. It was pointed out that the main problem is lack of stability under GC conditions. Dissociation of the chelates results in a smaller peak and a build-up of reactive metal ions. An improvement of the method could be achieved by addition of tfaH to the carrier gas of the GC equipped with aTCD" orFID" . ... 

The enthalpies and entropies of formation of intermetallic compounds between transition metals and rare earth or actinide elements are reported in tables 5-15. As can be seen, data are available for late transition metals. For early transition metals some data concerning the U-Zr, U-Nb, U-Mo solid solutions have been found and are reported in table 16. When calorimetric experiments have been performed in the liquid state, the values of the partial or integral enthalpies of mixing are reported in tables 17-20. These data concern only rare-earth-based alloys with Ni, Co, Fe and Mn. 

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