Osmium thermodynamic propertie

Plutonium-noble metal compounds have both technological and theoretical importance. Modeling of nuclear fuel interactions with refractory containers and extension of alloy bonding theories to include actinides require accurate thermodynamic properties of these materials. Plutonium was shown to react with noble metals such as platinum, rhodium, iridium, ruthenium, and osmium to form highly stable intermetallics. 

Plutonium-noble metal compounds have both technological and theoretical importance. Modeling of nuclear fuel interactions with refractory containers and extension of alloy bonding theories to include actinides require accurate thermodynamic properties of these materials. Plutonium was shown to react with noble metals such as platinum, rhodium, iridium, ruthenium, and osmium to form highly stable intermetallics. Vapor pressures of phases in these systems were measured by the Knudsen effusion technique. Use of mass spectrometer-target collection apparatus to perform thermodynamic studies is discussed. The prominent sublimation reactions for these phases below 2000 K was shown to involve formation of elemental plutonium vapor. Thermodynamic properties determined in this study were correlated with corresponding values obtained from theoretical predictions and from previous measurements on analogous intermetallics. 

Hirschmann M. (1991). Thermodynamics of multicomponent olivines and the solution properties of (Ni,Mg,Ee)2Si04 and (Ca,Mg,Fe)2Si04 olivines. Amer. Mineral, 76 1232-1248 Hirt B., Herr W, and Hoffmeister W. (1963). Age determinations by the rhenium-osmium method. In Radioactive Dating, International Atomic Energy Agency, Vienna. 

First of all, we must realize that the most important property of the electroactive polymer, as far as mediation is concerned, is its redox potential. To mediate a reduction of a solution species, the redox potential of the electroactive layer must be less positive than that of the analyte for the mediated oxidation process, the reverse is the case. This means that the osmium polymers under consideration here which have a redox potential of about 250 mV, are thermodynamically able to mediate the reduction of Fe(III) to FeCII), but not the reverse process (see Fig. 8.24), since the formal potential of the Fe(III/II) couple is 450 mV. The difference in the two redox potentials can be considered the driving force for the mediating process. On the basis of these considerations, it is clear that the mediated reduction of Fe(III) [as in Eq. (38)] is irreversible. 

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