High-resolution electron microscopy of crystal defects in C70-toluene solvate

Defects in C70 x C6H5CH3 were examined using transmission electron microscopy. Two types of defects with respect to (001) and [011] were observed. The former is an inter-grain of BCT phase in Amm2 orthorhombic matrix, whereas the latter is a twin. Origins of the observed defects were determined to be of a shearing nature in the directions of [010] and <011>. In addition, an attempt is made to explain the decagonal symmetry of the compound, as reported by several authors, with respect to strain relaxation by observing defects as well as a multiple-twinning model described by Fleming et al. (Phys. Rev. B44: 888 (1991)). The conversion of C70-toluene solvate into C70 pure phases is discussed in terms of the defects.