Thermal and mechanical behaviour of the C60·2S8 monoclinic compound

The thermal expansion tensor of the C60·2S8 solvate as determined through X-ray measurements in the 90–470 K range is found to be strongly anisotropic. The intermolecular interactions which account for the weakest thermal expansion direction and which are likely to be the strongest ones are mainly C60–S8 interactions. Furthermore, contrary to what is observed for other solvates, C60·2S8 resists desolvation through mechanical treatment. It is shown that C60·2S8 local order is maintained in the resulting non-crystalline phase. On heating, this phase reverts to crystalline C60·2S8 near the melting temperature of pure sulphur. These results support strong C60–S8 interactions.