scholarly journals The Temperature Dependence of the Isotope Effect for Electromigration of Potassium Ions in Molten Potassium Nitrate

1968 ◽  
Vol 23 (11) ◽  
pp. 1779-1782
Author(s):  
Arnold Lundén ◽  
Alf Ekhed
Keyword(s):  
Thermal Decomposition ◽  
Temperature Dependence ◽  
Isotope Effect ◽  
Separation Factor ◽  
Mass Effect ◽  
Potassium Nitrate ◽  
Relative Difference ◽  
Potassium Ions ◽  
Heavy Isotope ◽  
Significant Enrichment

The relative difference (Δb/b) between the electromigration mobilities of 39K and 41K in molten KNO3 has been measured over the range 354° to 586°C. The mass effect, μ= (Δb/b)/(Δm/m), becomes larger when the temperature is increased, following the relation—,u =0.0385+0.000124 (t-337)where t is the temperature in °C. Due to thermal decomposition, the nitrate is partly converted to nitrite, but it is proved by performing experiments with different initial concentrations of nitrite, that the isotope effect for potassium is not influenced noticeably by the concentration of the anions.The experiment is designed to give an enrichment of the heavy isotope 41K in a small anode compartment and in the upper part of the separation tube. However, it was possible to establish that a slight, but significant, enrichment of the light isotope 39K was obtained in the lower part of the separation tube, i. e. just above the opening into the large cathode compartment. A separation factor of 1.003 was estimated for this enrichment effect, which is due to non-ideal conditions of the experiment.

Cation Mobilities, Including Isotope Effects, for Electromigration in Molten Mixtures of Potassium and Rubidium Nitrate

1979 ◽  
Vol 34 (10) ◽  
pp. 1207-1211 ◽  
Author(s):  
Alf Ekhed ◽  
Dr. Arnold Lundén
Keyword(s):  
Temperature Dependence ◽  
Isotope Effect ◽  
Isotope Effects ◽  
Mass Effect ◽  
Potassium Ions ◽  
Rubidium Nitrate ◽  
Mole Percent ◽  
The Difference

Abstract Electromigration of cations has been studied in molten KNO3 -RbNO 3 mixtures as a function of concentration (11 -94 mole % RbNO3 , about 380 °C) and temperature (about 10 mole % RbNO3 , 378 -560 °C). The mobility of K+ is slightly larger than that of Rb+ at all concentrations, the difference being about 3% in KNO3 -rich and 2% in RbNO3 -rich mictures. Neither for potassium nor for rubidium is the isotope effected affected much by the composition of the melt, although there is a tendency that the isotope effect for rubidium is somewhat larger in mixtures than in pure salts. Both isotope effects have the same temperature dependence in the investigated mixture as in the pure salts. The isotope effects for potassium and rubidium have also been determined for ternary NaNO3 -KNO3 -RbNO3 mixtures containing about 5 mole percent of NaNO3 and of RbNO3 . For comparison, a study of the mass effect for potassium ions in NaNO3 -KNO3 is also reported.

The Temperature Dependence of the Isotope Effect for Electromigration of Rubidium Ions in Molten Rubidium Nitrate

1972 ◽  
Vol 27 (7) ◽  
pp. 1135-1138
Author(s):  
Arnold Lundén ◽  
Allan Floberg ◽  
Ronny Mattsson
Keyword(s):  
Temperature Dependence ◽  
Isotope Effect ◽  
Mass Effect ◽  
Relative Difference ◽  
Rubidium Nitrate ◽  
Similar Temperature Dependence ◽  
Similar Temperature

Abstract The relative difference (Δb/b) between the internal electromigration mobilities of 85Rb and 87Rb in molten RbNO3 has been measured over the range 355 to 500 °C. The mass effect μ = (Δb/b)/(Δm/m) has a complicated temperature dependence. Thus, the largest mass effect, -μ=0.061, was obtained at 445 °C, while it is about 0.033 at 350 °C and 0.041 at 500 °C. A similar temperature dependence was found by SAITO et al. for μNa in pure NaNO3, and for both μRb and μNa maxima have been found also in nitrate mixtures (in KNO3-RbNO3 and NaNO3-KNO3)

scholarly journals The Isotope Effect for Electromigration of Sodium Ions in Molten Sodium Nitrate

1972 ◽  
Vol 27 (2) ◽  
pp. 288-293
Author(s):  
Nobufusa Saito ◽  
Katsumi Hirano ◽  
Kohei Okuyama ◽  
Isao Okada
Keyword(s):  
Melting Point ◽  
Isotope Effect ◽  
Sodium Nitrate ◽  
Mass Effect ◽  
Relative Difference ◽  
Internal Mass ◽  
Sodium Ions ◽  
Molten Sodium

AbstractThe relative difference (Δb/b) between the internal electromigration mobilities of 22Na and 24Na in molten NaNO3 has been measured in the range 340 - 515 °C. The internal mass effect, μint= (Δb/b)/(Δm/m) is - 0.056 at 340 °C (melting point 308 °C), - 0.079 at 435 °C and - 0.068 at 515 °C. The errors in μint are ±0.002.

The Isotope Effect of Electromigration in Some Solid Alkali Halides

1971 ◽  
Vol 26 (2) ◽  
pp. 300-307 ◽  
Author(s):  
Takeshi Morimoto ◽  
Isao Okada ◽  
Nobufusa Saito
Keyword(s):  
Activation Energy ◽  
Ionic Conductivity ◽  
Single Crystal ◽  
Potassium Chloride ◽  
Isotope Effect ◽  
Lithium Fluoride ◽  
Alkali Halides ◽  
Mass Effect ◽  
Relative Difference ◽  
Solid Alkali Halides

The isotope effect of electromigration in some solid alkali halides was determined in their intrinsic ionic conductivity region. The external cationic mass effect (i. e., relative difference in cationic mobility/relative difference in mass) of lithium fluoride, chloride, bromide and iodide and potassium chloride was -0.243, -0.207, -0.195, -0.190 and -0.254, respectively, at 750, 540, 470, 370 and 600 °C, respectively. No difference of the mass effect was found between polycrystalline and single crystal potassium chloride. When the available data for the mass effect of the solid salts are plotted against the activation energy for electric conductance, there is a tendency for the mass effect to increase as the activation energy increases.

Isotope Effect of Cation Electromigration in Molten Lithium Chloride-Nitrate-Mixtures

1975 ◽  
Vol 30 (1) ◽  
pp. 75-78 ◽  
Author(s):  
Vladislav Ljubimov ◽  
Arnold Lundén
Keyword(s):  
Isotope Effect ◽  
Lithium Chloride ◽  
Isotope Effects ◽  
Mass Effect ◽  
Relative Difference ◽  
Lithium Ions ◽  
Lithium Isotopes ◽  
Decomposition Products ◽  
Molten Lithium

Abstract Molten mixtures of lithium chloride and nitrate, including the decomposition products nitrite and oxide, were electrolysed at about 600 °C with gaseous electrodes. The relative mobilities of the lithium isotopes were studied. The mass effect (relative difference in mobility divided by relative difference in mass) is 0.063 for a mixture with 20% Cl- and 0.069 for 80% CI-, which both are more than 30% smaller than those interpolated from the isotope effects of pure LiNO3 and LiCl. It is concluded that the lithium ions interact more strongly (with the anions and/or with each other) in a melt containing several anions than in a pure melt. The experiments also yield some information about the mobilities of the anions present in the melt.

Neutral Solvolysis of Acyl Carbon and the Temperature Dependence of the Kinetic Solvent Isotope Effect

1975 ◽  
Vol 53 (6) ◽  
pp. 869-877 ◽  
Author(s):  
B. Rossall ◽  
R. E. Robertson
Keyword(s):  
Temperature Dependence ◽  
Isotope Effect ◽  
Solvent Isotope Effect ◽  
Acyl Carbon ◽  
Rate Of Hydrolysis ◽  
Solvent Isotope ◽  
Neutral Conditions ◽  
Hydrolysis Of

The temperature dependence of the rate of hydrolysis of benzoic, phthalic, and succinic anhydrides have been determined in H2O and D2O under "neutral" conditions. Corresponding data have been obtained for methyl trifluoroacetate. While both series supposedly react by the same BAc2 mechanism, remarkable differences are made obvious by this investigation. Possible sources of such differences are proposed.

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