Barium equilibrium conductivity

Conditioning of the manganese oxide suspension with each cation was conducted in a thermostatted cell (25° 0.05°C.) described previously (13). Analyses of residual lithium, potassium, sodium, calcium, and barium were obtained by standard flame photometry techniques on a Beckman DU-2 spectrophotometer with flame attachment. Analyses of copper, nickel, and cobalt were conducted on a Sargent Model XR recording polarograph. Samples for analysis were removed upon equilibration of the system, the solid centrifuged off and analytical concentrations determined from calibration curves. In contrast to Morgan and Stumm (10) who report fairly rapid equilibration, final attainment of equilibrium at constant pH, for example, upon addition of metal ions was often very slow, in some cases of the order of several hours. 

KNs. The d.c. electrical conduction of KN3 in aqueous-solution-grown crystals and pressed pellets was studied by Maycock and Pai Verneker [127]. The room-temperature conductivity was found to be approximately 10" (ohm cm) in the pure material. Numerical values for the enthalpies of migration and defect formation were calculated from ionic measurements to be 0.79 0.05 and 1.43 0.05 eV (76 and 138 kJ/mole), respectively. In a subsequent paper [128], the results were revised slightly and the fractional number of defects, the cation vacancy mobility, and the equilibrium constant for the association reaction were calculated. The incorporation of divalent barium ions in the lattice was found to enhance the conductivity in the low-temperature region. Assuming the effect of the divalent cation was to increase the number of cation vacancies, the authors concluded that the charge-carrying species is the cation, and the diffusion occurs by means of a vacancy mechanism. 

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