Intercalation compounds of α-zirconium hydrogen phosphate with heterocyclic bases and their ac conductivity

Abstract

Intercalation compounds of α-zirconium hydrogen phosphate with diazoles (pyrazole, imidazole) and diazines (pyridazine, pyrimidine and pyrazine) were prepared by equilibrating the host matrix, pre-swelled with ethanol and/or 1-butanol, with diluted solutions of the bases, for one to two weeks. Composition data and interlayer distance values suggest that the guests are accommodated in the interlayer region as a monolayer of molecules lying flat or slightly tilted with respect to the surface of the sheet. The ac conductivities of diazole intercalates, determined by impedance measurements on pellets over a temperature range of 80–160°C, are higher than those of diazine. At 120°C the pirazole intercalate had a conductivity of 1.4×10 -6S cm -1 (9×10 -6S cm -1 when the intercalate was prepared in pellicular form). The data have been tentatively interpreted on the basis of a transport mechanism involving proton transfer from protonated guest molecules to a nonprotonated neighbour ones, followed by the rotation of the neutral (or protonated) species.