Alexei Potapov

Electrical Conductivity of Melts Containing Rare-Earth Halides. I. MCl-NdCl3 (M = Li, Na, K, Rb, Cs)

The electrical conductivity of molten MCl-NdCl3 (M = Li, Na, Rb and Cs) has been measured from the liquidus temperature up to ~ 1180 K. The measurements were performed in usual U-shaped capillary quartz cells with platinum electrodes. The molar conductivity (Λ) has been computed by using literature data on the densities of the binary systems. In all cases, when the temperature range exceeds about 100 K, the plot lnΛ vs. 1/T is not a straight line. The activation energy of the conductivity does not remain constant but reduces with increasing temperature. In the specific and molar conductivity isotherms strong deviations from additivity are noted. The results are discussed in terms of octahedral local coordination of Nd3+ over the entire concentration range.

Viscosity of Molten Rare Earth Metal Trichlorides II. Cerium Subgroup

The kinematic viscosity of molten LaCl3, CeCl3, PrCl3, NdCl3, and SmCl3 was measured directly by using a capillary viscometer made of quartz and a transparent electric furnace. Viscosity of molten PmCl3 and EuCl3 was estimated using common tendencies in the lanthanides row. The dynamic viscosity was computed by using the most reliable density data taken from literature. The viscosity of molten lanthanides trichlorides at the same temperature changes slightly within a cerium lanthanides subgroup. Molten EuCl3 perhaps has abnormally low viscosity.

The Molar Volume of Molten Mixtures of MCl-LnCl2 (M = Alkali Metals, Ln = Lanthanoides)

Empirical equations for the density and molar volume of molten binary mixtures of MCl-LnCl2 and MCl-MeCl2 (M = alkali metals; Ln = lanthanoides; Me = Ca, Sr, Ba) based on the density of individual components are suggested. The equations, taking into account the deviations of the molar volumes from their additive values, are applicable to all binary systems involving known rare earth dichlorides.

Maximum on the Electrical Conductivity Polytherm of Molten TeCl4

Abstract The electrical conductivity of molten TeCl4 was measured up to 761K, i.e. 106 degrees above the normal boiling point of the salt. For the first time it was found that TeCl4 electrical conductivity polytherm has a maximum. It was recorded at 705K (κmax=0.245 Sm/cm), whereupon the conductivity decreases as the temperature rises. The activation energy of electrical conductivity was calculated.

Electrical Conductivity of Molten CdCl2 at Temperatures as High as 1474 K

Abstract The electrical conductivity of molten CdCl2 was measured across a wide temperature range (ΔT=628 K), from 846 K to as high as 1474 K, i.e. 241° above the normal boiling point of the salt. In previous studies, a maximum temperature of 1201 K was reached, this being 273° lower than in the present work. The activation energy of electrical conductivity was calculated.

Electrical Conductivity of Molten ZnCl2 at Temperature as High as 1421 K

Abstract The electrical conductivity of molten ZnCl2 was measured in a wide temperature range (ΔT=863 K) to a temperature as high as 1421 K that is 417 degrees above the boiling point of the salt. At the temperature maximum of the own vapor pressure of the salt reached several megapascals.

Hardness of a Crystal Lattice as Consequence of Quantum “Freezing” of Atomic Degrees of Freedom

It has been shown that in the classical computer model the “matter of a crystal” has the kinetic and mechanical properties of a dense gas or a simple liquid at any temperature, including the area near the absolute zero. Agreement with the experiment and a stable hard crystal structure with high enough real activation energy (for instance E ≈ 40RTm) can be obtained if quantum effects and especially quantum “freezing” of atomic degrees of freedom are introduced in the model.

Chlorine Solutions in Molten Alkali Chlorides

Electronic absorption spectra of gaseous chlorine and their saturated solutions in molten alkali chlorides were studied in wide ranges of temperature and wavelength. It was found that gaseous chlorine has a wide absorption band between 20 000 and 43 500 cm−1. There is a tendency to both widening of the band and shifting of the absorption maximum to the short-waves region with rising temperature. The absorption bands of saturated solutions of chlorine in all molten alkali chlorides show a maximum in the neighborhood of 30 000 cm−1. A good correlation was found between the optical density of molten salt-Cl2 systems and the solubility of chlorine.