Reactions between C 6 0 and FeCl 3 were carried out with and without Cl 2 gas. Chlorinated C 6 0 was also produced. The product C 6 0 (FeCl 3 ) 2 formed with Cl 2 gas in the sample preparation was a black insulating powder inside and outside the dry box. Infrared (IR) spectroscopy showed that, when C 6 0 (FeCl 3 ) 2 is exposed to air, FeCl 3 leaves the sample and C 6 0 remains. Coherent (Bragg) X-ray diffraction was not observed from C 6 0 (FeCl 3 ) 2 although polycrystalline C 6 0 was used in the reaction. For the product from the reaction between C 6 0 and FeCl 3 without Cl 2 gas, only very weak IR absorption lines from C-Cl bonding were observed, and the X-ray diffraction pattern showed FeCl 3 and C 6 0 peaks. This shows that C 6 0 does not react well with FeCl 3 without Cl 2 gas in the sample preparation. Thus, Cl 2 gas enhances the reaction between C 6 0 and FeCl 3 , produces a noncrystalline product, and is not responsible for the conductivity in chlorinated C 6 0 compounds.