Journal of Physical Chemistry B, Vol.103, No.12, 2050-2053, 1999
Solvent molecules in crystalline C-60
A set of samples C-60(cr) was prepared and studied using X-ray diffraction analysis,H-1 NMR, differential scanning calorimetry (DSC), and gas adsorption methods for elucidating the state of residual solvents in C-60. The solvent molecules were found to be adsorbed at interfaces of the microcrystals of C-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-60.
Keywords:ORIENTATIONAL ORDERING TRANSITION;SOLID C-60;PRESSURE-DEPENDENCE;PHASE-TRANSITION;FULLERENE C-60;X-RAY;DSC;C60