Solvent Molecules in Crystalline C60

A set of samples C{sub 60}(cr) was prepared and studied using X-ray diffraction analysis, {sup 1}H NMR, differential scanning calorimetry (DSC), and gas adsorption methods for elucidating the state of residual solvents in C{sub 60}. The solvent molecules were found to be adsorbed at interfaces of the microcrystals of C{sub 60}(cr); sintering of the microcrystals on heating is assumed to be responsible for entrapping some of the solvent molecules in the sample. This may explain the difficulty of removal of the solvents from fullerene samples. The disappearance of the orientational phase transition in DSC curves of mechanically treated samples was interpreted in terms of space defects in the crystals of C{sub 60}.