Abstract Densities, heat capacities and enthalpies of dilution at 25° C and osmotic coefficients at 37° C were measured for N-octyl-, N-decyl-and N-dodecyl-pyridinium chlorides in water over a wide concentration region. Conductivity measurements were performed in order to evaluate the cmc and the degree of counterion dissociation. Partial molar volumes, heat capacities, relative enthalpies and nonideal free energies and ...