VOLTAIC CELLS IN FUSED SALTS: PART IV. ELECTRODE POTENTIALS OF THE SYSTEMS: Tl/TlCl (KCl–NaCl), Cu/CuCl (KCl–NaCl), Cu/CuCl2 (KCl–NaCl), Cr/CrCl2 (KCl–NaCl), AND Cr/CrCl3 (KCl–NaCl). REDOX POTENTIALS OF THE SYSTEMS: Pt/CuCl, CuCl2 (KCl–NaCl), AND Pt/CrCl2, CrCl3 (KCl–NaCl)

1958 ◽  
Vol 36 (7) ◽  
pp. 1103-1115 ◽  
Author(s):  
S. N. Flengas ◽  
T. R. Ingraham

Using a Ag/AgCl (KCl–NaCl) reference electrode, the standard electrode potentials of the systems Tl/TlCl (KCl–NaCl), Cu/CuCl (KCl–NaCl), Cu/CuCl2 (KCl–NaCl), Cr/CrCl2 (KCl–NaCl), and Cr/CrCl3 (KCl–NaCl) were measured and found to be: 0.650 volt at 680 °C, and 0.250, −0.175, 0.755, and 0.423 at 700 °C. respectively. The standard redox potentials of the systems Pt/CuCl2, CuCl (KCl–NaCl), and Pt/CrCl3, CrCl2 (KCl–NaCl) were also measured at 700 °C. and found to be 0.600 and 0.240 volt respectively. The effect of temperature on the electromotive forces of the above cells was measured and the heats of the cell reactions were calculated from the data.

1958 ◽  
Vol 36 (12) ◽  
pp. 1662-1667 ◽  
Author(s):  
S. N. Flengas ◽  
T. R. Ingraham

Using a Ag/AgCl (KCl–NaCl) reference electrode, the standard electrode potentials of the systems Sn/SnCl2 (KCl–NaCl), Fe/FeCl2 (KCl–NaCl), and Mn/MnCl2 (KCl–NaCl) were determined at 700 °C and found to be 0.370 v, 0.520 v, and 1.205 v respectively. In each of the systems the Nernst equation was found to be applicable over the range of concentrations investigated.The effect of temperature on the electromotive forces of the above cells was measured and the heats of the cell reactions were calculated from the data.


1957 ◽  
Vol 35 (11) ◽  
pp. 1254-1259 ◽  
Author(s):  
S. N. Flengas ◽  
T. R. Ingraham

Using a reversible silver – silver chloride reference electrode, described in the first paper of this series, standard electrode potentials have been established for the systems lead – lead chloride, zinc – zinc chloride, and nickel – nickelous chloride, in melts containing equimolar quantities of KCl and NaCl. Deviations from ideality were observed, and these were attributed to the formation of complexes. Dissociation constants for the complexes were calculated. The effect of temperature on the electromotive forces of the voltaic cells was also measured, and the heats of the cell reactions were calculated from the data.


1965 ◽  
Vol 43 (1) ◽  
pp. 197-205 ◽  
Author(s):  
R. Baboian ◽  
D. L. Hill ◽  
R. A. Bailey

The methods of potentiometry and polarography have been used to study the Ti(II) and Ti(III) ions in solution in the LiCl–KCl eutectic at 450 °C and 550 °C. Solutions of Ti(II) were prepared by anodic dissolution of Ti metal, and Ti(III) solutions by coulometric titration of Ti(II) by Pt(II). Apparent standard electrode potentials were measured for the Ti(II)/Ti and Ti(III)/Ti(II) couples against the Pt(II)/Pt and Ag(I)/Ag reference electrodes. Values obtained on the mole fraction scale with a Pt(II)/Pt reference electrode were[Formula: see text]Polarographic waves for oxidation and reduction of Ti(II), and for reduction of Ti(III), were observed.


1957 ◽  
Vol 35 (10) ◽  
pp. 1139-1149 ◽  
Author(s):  
S. N. Flengas ◽  
T. R. Ingraham

A reversible silver − silver chloride reference electrode for use in melts at high temperatures has been developed. It was found that the solution of silver chloride in an equimolar mixture of KCl–NaCl melt is ideal for the range of concentrations studied, i.e. 1.0 × 10−3 to 6.0 × 10−2 mole fraction of AgCl.The electromotive force of the voltaic cell[Formula: see text]in which the half-cell to the right contains the above-mentioned reference electrode, was measured as a function of CoCl2 concentration. The applicability of the Nernst equation to this system was established. Deviation from ideality was observed in the case of the solution of CoCl2 in the melt solvent, and this was attributed to the formation of a complex. The dissociation constant of this complex was calculated as 4.50 × 10−2 at 710 °C.The effect of temperature on the electromotive force of this cell was also measured, and the heat of the cell reaction in the presence of solvent (Co + 2AgCl → CoCl2 + 2Ag) was calculated from the data as 22.8 ± 1.3 kcal.The thermodynamic significance of the standard electrode potential of the Co–Ag voltaic cell, derived experimentally as 0.324 volt, is discussed briefly.


1958 ◽  
Vol 36 (5) ◽  
pp. 780-788 ◽  
Author(s):  
S. N. Flengas ◽  
T. R. Ingraham

Using a silver–silver chloride reference electrode, the standard electrode potential his been established for the equilibrium Cd|Cd++ in melts containing equimolar quantities of KCl and NaCl. The experimentally obtained standard potential was greater than that calculated from theoretical thermodynamic data. This difference was attributed to the formation of a cadmium complex in the melt. A dissociation constant for the complex was calculated.The effect of temperature on the electromotive force of the silver–cadmium voltaic cell was also measured, and the heat of the cell reaction was calculated from the data. To extend the temperature range of the cadmium data, a cadmium–lead alloy was used in the higher temperature experiments. To correlate these data with those for the pure cadmium system, the activity coefficients of cadmium in the alloy were determined electrometrically using the silver–silver chloride electrode as a reference. It was found that the activity coefficients were in agreement with previously published data obtained at lower temperatures using a pure cadmium reference electrode. The activity coefficients were virtually independent of temperature but showed large positive deviations from unity when the mole fraction of cadmium was decreased below about 0.8.


1961 ◽  
Vol 39 (4) ◽  
pp. 773-784 ◽  
Author(s):  
S. N. Flengas

Using a silver – silver chloride reference electrode, the electrode potentials of the system U, UCl3(KCl, NaCl) and the redox potentials of the system Pt, UCl3, UCl4(KCl, NaCl) were measured at various concentrations of the uranium chlorides and at temperatures between 650 and 850 °C.From the results, the electrode potential of the system U, UCl4(KCl, NaCl) was calculated. In addition, the activity coefficients and partial molal properties of dilute solutions of UCl3 and UCl4 in the equimolar mixture of potassium and sodium chlorides were calculated.


1993 ◽  
Vol 71 (9) ◽  
pp. 1283-1289 ◽  
Author(s):  
G.J. Kipouros ◽  
S.N. Flengas

The standard electrode potentials for the formation of the pure solid and molten compounds Li2ZrCl6, Li2HfCl6, Na2ZrCl6, Na2HfCl6, K2ZrCl6, K2HfCl6, Cs2ZrCl6, and Cs2HfCl6 have been calculated from measured vapour pressures corresponding to their thermal decomposition at equilibrium and from available thermochemical data. Reversible potentials for the formation of Na2ZrCl6 and of K2ZrCl6 in solution according to the reaction[Formula: see text]where A is Na or K, have been calculated from available equilibrium vapour pressures as functions of the mole fractions of the alkali hexachlorocompounds. Standard potentials for the above reaction and "formal" potentials are also given. The latter are useful in predicting the electrochemical behaviour of dilute solutions of the hexachlorozirconates in alkali metal chlorides.


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