Conductivity anomalies in mixed Na/Ag β-aluminas: evidence for a co-ionic effect?
Abstract A reinvestigation of mixed cation effects in Na/Ag β-aluminas shows that the conductivity isotherm contains both maxima and minima. Increases in conductivity are attributed to the co-ionic migration of Ag + ions. Decreases in conductivity indicate the trapping of interstitial cation pairs, e.g. (Ag 2 ) + by the interstitial O 2− ions. The positions of the conductivity minima (at approx. 8% and 40% Ag respectively) are interpreted by postulating the formation of stable complexes, such as [O 2− .(Na 2 ) + (NaAg) + ] and [O 2− .(Ag 2 ) 2 + ].