CHANGES OF MOLAR VOLUME FROM SOLID TO LIQUID AND SOLUTION - THE PARTICULAR CASE OF C-60

Partial molar volumes of solid C-60 at infinite dilution have been det ermined from high precision density measurements in 12 organic solvent s characterized by different physicochemical properties and solubilizi ng capacity. Results appear unusual with respect to almost all organic solid substances in that not only are the values far smaller than the estimated molar volume of liquid C-60 but they even remain lower than the molar volume of the pure solid C-60. The results which range from 350 to 440 cm(3) mol(-1) reveal the non-uniform behavior of this rema rkable rigid molecule in solution. Although no readily obvious relatio nship between the partial molar volumes of C-60 in a particular solven t and properties of the solvent has been found, the observed rough dep endence on the molar volume of the solvent might be interpreted in ter ms of the arrangement of the molecules differing in size and shape, an d how they fit together in solution.