George J. Janz

Molten salts: Volume 4, part 2, chlorides and mixtures—electrical conductance, density, viscosity, and surface tension data

Data on the electrical conductance, density, viscosity, and surface tension of fluoride mixtures have been systematically collected and evaluated. Results are given for 44 binary mixtures over a range of compositions and temperatures. Values of the above properties for the single salts have been updated in accord with previously advanced recommendations.

Raman Spectra and Ionic Interactions in Molten Nitrates

A simple experimental assembly designed for use with a conventional Toronto‐type source and capable of use at temperatures up to 700°C is described for the Raman technique. Application to the series of molten inorganic salts Li, Na, K, Cs, Rb, and Ag/NO3, and selected mixtures of these, is reported. The Raman frequencies, relative intensities, depolarization ratios, and vibrational force constants are discussed. A regular variation of the Raman frequencies and force constants which correlates with the change in the polarizing power of the cationic environment is noted. The results are examined in the light of current views on the structure of molten salts.

The electrolytic deposition of carbon from fused carbonates

Abstract : The cathodic deposition of carbon from fused carbonates is reported. The yield is quantitative under favorable conditions (600 C, Ar atmosphere) but diminishes in the presence of CO2 and with rise in temperature. If the melt does not contain Li(+) ions, alkali metal is the only cathodic product. The distinctive feature of the electrolytic carbon is an enhanced electrochemical activity; thus the rest potential is 0.8V negative with respect to commercial carbons. A thermodynamic treatment correlates this activity with the occlusion of oxide ions in the highly porous carbon deposit. The marked solvent effect is shown to arise in the same way. (Author)

Molten Salts: Volume 3 Nitrates, Nitrites, and Mixtures: Electrical Conductance, Density, Viscosity, and Surface Tension Data

Data on the electrical conductance, density, viscosity, and surface tension of nitrate—nitrate, nitrite—nitrite, and nitrite—nitrate mixtures have been systematically collected and evaluated. Results are given for some 71 binary mixtures over a range of compositions and temperatures. Values of the above properties for the single salts have been updated in accord with previously advanced recommendations.

The thermodynamics of corrosion in molten carbonates: Application of E/pCO2 diagrams

Abstract The corrosion of metals in fused carbonates is discussed in terms of a diagrammatic presentation of the thermodynamic data. The treatment closely resembles that of Pourbaix and Littlewood; diagrams are plotted of E vs pCO2, where E is the redox potential of the system, and pCO2  log10(CO2). Each diagram is divided into three regions which mark the limits of stability at unit activity of the pure metal, metal oxide and liquid metal carbonate. In the oxide region the metal may become passivated, but this depends on structural factors and requires experimental confirmation. The electrochemical series in molten carbonates is presented, and the significance of pCO2 in relation to acid—base behaviour is discussed.

Molten Salts Data: Diffusion Coefficients in Single and Multi‐Component Salt Systems

The property of diffusion is one of the basic properties of fluid systems. In molten salts, more than 700 studies have been reported to August, 1980, with more than 15 diffusion measurement techniques. A critical examination of these studies with a review of the techniques is presented. The results for more than 140 salt systems are reported in this communication as a series of data tables, with numerical values, value judgements, and literature citations. Silicates, slags, and oxide melts are excluded.

Molten Salts Data as Reference Standards for Density, Surface Tension, Viscosity, and Electrical Conductance: KNO3 and NaCl

Accuracy estimates for physical property measurements are usually based on somewhat subjective quality judgements and the difficulties encountered in interpreting accuracy statements in the literature are frequently compounded through lack of details on the methods of measurements, chemical purity, and related experimental aspects. In the present communication we report the results of a Standards Program initiated in 1973 with participating laboratories in Czechosloskia, German Democratic Republic‐DDR, Japan, Norway, Poland, Rumania, and U.S.A. Potassium nitrate (m.335 °C) and sodium chloride (m 800 °C) were selected as the two reference salts for the properties: density, surface tension, viscosity, and electrical conductance. The results of the measurements have been critically examined, and are reported herewith. It has been possible to resolve some of the difficulties encountered in accuracy estimates through this ’’round‐robin’’ series of measurements, and to up‐grade some of the data‐sets to calibrat...

SILVER, SILVER CHLORIDE ELECTRODES

The silver, silver chloride electrode (like its mercury-based analogue, the calomel electrode) belongs to the class of reference electrodes of the second kind. These are three-phase electrodes reversible to anions in solution-that is to say, their potentials are determined by the activity in solution of the appropriate anions, in accordance with the thermodynamically-based Nernst relation. The three phases, in contact and in equilibrium with each other, consist of a metal, a solid, sparingly soluble salt formed by the cation of the metal with the anion to which the electrode is reversible, and a solution containing this same anion. Thus, the silver, silver chloride electrode, normally represented

Molten Carbonate Electrolytes: Physical Properties, Structure, and Mechanism of Electrical Conductance

Abstract : Results are presented of an investigation of the properties of surface tension, density, and electrical conductance for molten Li2CO3, Na2CO3, and K2CO3 and some mixtures in the temperature range of 750 to 1000 C. The surface tensions are approximately twice the values for the corresponding chlorides: the densities and electrical conductance are quite comparable to those of the chlorides. The ionic nature of the molten carbonates is examined from the physicochemical criteria based on these properties: and the mechanism of electrical transport is considered in the light of current theoretical concepts. Relative to Na2CO3 - K2CO3 mixtures, the surface tensions and partial molal volumes indicate but little deviations from the predictions for thermodynamically ideal mixtures. (Author)

Molecular Structure and Vibrational Spectra of Ethyl Cyanide

The infrared spectra for the gaseous and liquid states, and the Raman spectra for the liquid state, including intensity and polarization data, are reported for ethyl cyanide (C2H5CN). A normal coordinate treatment has been made for four planar and five nonplanar skeletal vibrational modes. The observed spectra are in accord with a C8 model for this molecule. A complete assignment of frequencies to the fundamental modes of vibration is made for ethyl cyanide. From the spectroscopic data, the height of the barrier hindering internal rotation is estimated to be 5200 cal. The thermodynamic functions for ethyl cyanide have been calculated to 1000°K.