Ultrasonic velocity, conductivity, viscosity and calorimetric studies of copper(I) and sodium perchlorates in cyanobenzene, pyridine and cyanomethane

Abstract

Ultrasonic velocities (u), densities (ρ), viscosities (η), molar conductivities (Λ) and enthalpies of solution (Δ_solH) of CuClO₄ and NaClO₄ have been measured in cyanobenzene, pyridine and cyanomethane at 298, 308 and 318 K. These data have been used to calculate isentropic compressibilities (κ_s) of the salts and limiting ionic conductivities (λ^o_i), solvated ionic radii (r_i) and solvation numbers (n) for Cu⁺, Na⁺ and ClO₄^–. Cu⁺ is highly solvated in all three solvents with solvation decreasing in the order pyridine > cyanomethane > cyanobenzene. Na⁺ in all solvents is relatively less solvated and the solvation decreases in the order cyanomethane cyanobenzene pyridine. The ClO₄^– ion is poorly solvated in all three solvents. κ_s and Δ_solH^o data indicate that NaClO₄, in spite of its poor solvation in pyridine, shows strong structural effects which are attributed to strong pyridine–pyridine interactions.