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The standard electrode potentials (E°) of the following redox couples were determined in molten normalLiF‐BeF2‐ZrF4 false(65.6‐29.4‐5.0 normalm/normalo false(normalmole per centfalse) and normalLiF‐normalNaF‐KFfalse(46.5‐11.5‐42.0 normalm/normalofalse) at 500°C from emf measurements on galvanic cells using Ni(II)/Ni reference electrode, contained in a boron nitride compartment. The E° of the Ni(II)/Ni couple was set at 0.000V. In normalLiF‐BeF2‐ZrF4 : Be(II)/Be −2.120V, Zr(IV)/Zr −1.792V (not E°), Cr(II)/Cr −0.701V, Cr(III)/Cr(II) −0.514V, Fe(II)/Fe −0.410V, and Fe(III)/Fe(II) 0.166V. In normalLiF‐normalNaF‐KF : Fe(II)/Fe −0.390V and Fe(III)/Fe(II) −0.200V. The more anodic value of E° of the Fe(III)/Fe(II) couple (as compared to the Fe(II)/Fe couple) in normalLiF‐BeF2‐ZrF4 in comparison to normalLiF‐normalNaF‐KF reflects the higher acidity (modified Lux‐Flood concept) of the normalLiF‐BeF2− ZrF4 melt.

mentioning that the mechanism suggested by Breck and Lin is sufficiently similar to the mechanism of H + transport under an electric field, i.e., considering the transport of H + as a sort of "structural diffusion." In view of the fact that in these two cases the driving forces involved are quite different, this is an interesting thing to know. An electric field (for example a d-c field) will tend to align the solvent dipole and thus create more order, whereas a temperature gradient would tend to create more disorder by way of setting up a thermal energy gradient among the solvent molecules.To evaluate the ionic entropy of transport on an "absolute" basis, a study of the problem of standard state is necessary. We plan to discuss this subject in a forthcoming article.

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