Degradation of C70 in its hexagonal phase

The stability during a long time of a c70 vapour grown single crystal corresponding to the hexagonal (hcp) phase, has been studied by x-ray diffraction. At room temperature the symmetry of the crystal is orthorhombic. The domain structure of this phase is presented. A strong evolution of the mosaic spread is observed over a period of 4 months. It corresponds to a progressive destruction of the sample.