Conductance, viscosity, density, pmr spectra, and glass transition temperature measurements have been performed for the binary hydrate melt system calcium nitrate tetrahydrate-cadmium nitrate tetrahydrate. Chemical shift vs. composition plots for the water proton resonance indicate that in these melts the Ca2+ and Cd2+ ions are equally hydrated. Glass transition temperatures are a linear function of cation fraction of Cd2+ and decrease from 222 to 210° as XCd2+ increases from 0 to 1. Both conductance and fluidity exhibit a non-Arrhenius temperature dependence for all compositions and have been described in terms of three-parameter equations of the forms Λ = AΛT-1/2 exp[-kΛ/(T - T0,Λ)] and φ = AφT-1/2 exp[-kφ/(T - T0,φ)]. It is shown that the parameters in these equations have a simple dependence on composition such that T0,Λ = T0,φ for each composition, kΛ and kφ are composition independent, and ln AΛ and ln Aφ show identical linear dependences on composition. Plots of T0,Λ and T0,φ vs. XCd2+ parallel similar plots for the glass transition temperature, Tg. Both conductance and fluidity isotherms show negative deviations from additivity as a function of composition, primarily as a result of the composition dependence of the T0,Λ and T0,φ parameters.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry