Crystal Structure of Iron Chloride in Channels of Single-Walled Carbon Nanotubes

The crystal structure of iron chloride in channels of single-walled carbon nanotubes (SWCNTs) is investigated. The channels of SWCNTs with mixed conductivity and a diameter of ~1.4 nm are filled with iron chloride by means of the melt method. On the basis of high-resolution transmission electron microscopy (HRTEM) images, the crystal structure of the encapsulated iron chloride is modeled, and TEM images are produced. It is shown that the encapsulated iron chloride has a one-dimensional structure that differs from the three-dimensional structure with the $$R\bar {3}m$$ space group and the lattice parameters a = 3.5980 Å and c = 17.5360 Å. The filled SWCNTs are investigated via Raman spectroscopy. Modification of the electronic structure of the SWCNTs is revealed. The obtained data are important for applying filled SWCNTs in nanoelectronics, catalysis, sensors, biomedicine, electrochemical energy storage, spintronics, magnetic storage, and magnetic recording.