High resolution electron microscopy of (SN)_x

Abstract

Pristine and iodinated (SN)_x were studied by high resolution electron microscopy. High resolution electron micrographs showing lattice fringes up to 0.22 nm were obtained. In these electron micrographs, the texture of (SN)_x crystals was elucidated to be fibrillar or mosaic; the lattice fringes were observed in domains extended along the molecular axis (b-axis) and very narrow in the perpendicular direction. Each crystallite varied from place to place in size but maintained the b-axis orientation.

The high resolution image of iodinated (SN)_x did not show directly the location of iodine atoms and their presence was deduced only from the optical transform of the image. The optical transform showed that iodine atoms were not intercalated uniformly, but localized at the skin region on (SN)_x fibers, where the crystal lattice was highly distorted. Then the iodination of (SN)_x is supposed to result in the destruction of the crystal lattice by invasion of iodine atoms or to take place preferentially at a distorted crystal region.