IONIC CONDUCTIVITY OF POTASSIUM BROMIDE CRYSTALS

1964 ◽  
Vol 42 (11) ◽  
pp. 2195-2216 ◽  
Author(s):  
J. Rolfe
Keyword(s):  
Ionic Conductivity ◽  
Single Crystals ◽  
High Temperatures ◽  
Potassium Carbonate ◽  
Calcium Ions ◽  
Transport Number ◽  
Potassium Bromide ◽  
Negative Ion ◽  
Conductivity Measurements ◽  
Positive Ion

The conductivity of single crystals of potassium bromide has been measured as a function of temperature. Potassium carbonate was found to be sufficiently soluble at high temperatures in KBr to cause a conductivity due to negative ion vacancies. The ionic conductivity parameters of KBr were calculated from conductivity measurements on crystals containing known concentrations of potassium carbonate and calcium bromide without recourse to transport number experiments. A simple theory of association was found to be adequate to describe the interaction between calcium ions and positive ion vacancies. The solubility of free divalent impurities in KBr was also calculated from conductivity measurements. The following enthalpy values were found: for formation of a pair of Schottky vacancies, 2.53 eV; for the motion of positive ion vacancies, 0.665 eV; for the motion of negative ion vacancies, 0.87 eV; for the association of calcium ions and positive ion vacancies, 0.46 eV.

Ionic Conductivity of Rubidium Iodide Crystals

1973 ◽  
Vol 51 (3) ◽  
pp. 236-240 ◽  
Author(s):  
Suresh Chandra ◽  
John Rolfe
Keyword(s):  
Ionic Conductivity ◽  
Defect Formation ◽  
Formation Enthalpy ◽  
Negative Ion ◽  
Conductivity Measurements ◽  
Transport Parameters ◽  
Vacancy Migration ◽  
Strontium Ions ◽  
Positive Ion ◽  
Migration Enthalpy

The ionic conductivity of pure and strontium-doped rubidium iodide crystals was measured as a function of temperature. Eight transport parameters were calculated from the conductivity results by a nonlinear regression computation. The values obtained for the transport parameters were: Schottky defect formation enthalpy hs = 2.1 eV, entropy ss = 0.5 × 10−3 eV/deg; positive-ion vacancy migration enthalpy Δh1 = 0.60 eV, entropy Δs1 = 0.14 × 10−3 eV/deg; negative-ion vacancy migration enthalpy Δh2 = 1.6 eV, entropy Δs2 = 0.13 × 10−3 eV/deg; association enthalpy of strontium ions and positive-ion vacancies χ = 0.58 eV, entropy η = 0.22 × 10−3 eV/deg. Rubidium carbonate was found to have a negligible solid solubility in rubidium iodide, so that conductivity measurements could not be made on anion-doped crystals. The negative-ion vacancy migration parameters are thus not as accurately determined as the other transport parameters.

scholarly journals IONIC CONDUCTIVITY MEASUREMENTS OF BARIUM FLUORIDE SINGLE CRYSTALS

1976 ◽  
Vol 37 (C7) ◽  
pp. C7-337-C7-341 ◽  
Author(s):  
V. M. CARR ◽  
A. V. CHADWICK ◽  
D. R. FIGUEROA
Keyword(s):  
Ionic Conductivity ◽  
Single Crystals ◽  
Barium Fluoride ◽  
Conductivity Measurements

Ionic Conductivity of Potassium Bromide Crystals

1971 ◽  
Vol 49 (16) ◽  
pp. 2098-2105 ◽  
Author(s):  
Suresh Chandra ◽  
John Rolfe
Keyword(s):  
Defect Formation ◽  
Formation Enthalpy ◽  
Potassium Bromide ◽  
Negative Ion ◽  
Coulomb Interactions ◽  
Transport Parameters ◽  
Vacancy Migration ◽  
Charged Defects ◽  
Positive Ion ◽  
Migration Enthalpy

The electrical conductivity of single crystals of potassium bromide was measured as a function of temperature, and as a function of the concentration of calcium bromide or potassium carbonate impurity. The results were analyzed on the assumption that the observed conductivity was due entirely to the motion of separated anion and cation vacancies (Schottky defects), with Coulomb interactions between charged defects. Agreement between measured and calculated conductivities at all temperatures showed that this assumption was reasonable. The values obtained for transport parameters were: Schottky-defect formation enthalpy hs = 2.53 eV, entropy Ss = 10.3k; positive ion vacancy migration enthalpy Δh1 = 0.65 eV, entropy Δs1 = 1.89k; negative ion vacancy migration enthalpy Δh2 = 1.22 eV, entropy Δs2 = 7.30k; association of calcium ions and positive ion vacancies enthalpy x = 0.61 eV, entropy η = 2.23k, where k is Boltzmann's constant.

Characterization of New Ionically Conducting Peo-Based Networks by Diffusion, Elasticity Modulus and Ionic Conductivity Measurements

1992 ◽  
Vol 293 ◽  
Author(s):  
Herve Cheradame ◽  
F. Desbat ◽  
P. Mercier-Niddam ◽  
S. Boileau
Keyword(s):  
Diffusion Coefficient ◽  
Ionic Conductivity ◽  
Elasticity Modulus ◽  
Sol Gel ◽  
Cation Transport ◽  
Lithium Cation ◽  
Conductivity Measurements ◽  
Conducting Materials ◽  
Diffusion Studies

AbstractIonically conducting materials containing PEO were prepared from telechelic di(methyl-diethoxy-silane) PEO, synthesized by the hydrosilylation of telechelic diallyl-PEO with methyldiethoxysilane. The network is obtained by the usual sol-gel chemistry. Then, it is filled with LiClO4 by diffusion of the salt and further drying. A comparison is made with the same kind of materials crosslinked using urethane chemistry. Diffusion studies show that the diffusion coefficient of solvent is similar for both types of materials, whilst the ionic conductivity is higher for the networks crosslinked with siloxane bonds. An experiment of diffusion of LiClO4 without solvent showed that this salt has a diffusion coefficient of the order of 2.10-8 cm2.sec-1 at 34°C. The conductivity calculated from this determination is compatible with the mechanism of lithium cation transport by the diffusion of salt molecules. Elasticity modulus measurements show that the salt aggregates are essentially located within the crosslinks at low concentration, but also in the PEO chains for salt concentrations higher than 1 mol/l.

Influence of purity of NdF3 single crystals on their ionic conductivity

2012 ◽  
Vol 57 (3) ◽  
pp. 461-462 ◽  
Author(s):  
N. I. Sorokin ◽  
Z. I. Zhmurova ◽  
E. A. Krivandina ◽  
B. P. Sobolev
Keyword(s):  
Ionic Conductivity ◽  
Single Crystals
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