Effect of Cl2 in the interaction between C60 and FeCl3

Reactions between C60 and FeCl3 were carried out with and without Cl2 gas. Chlorinated C60 was also produced. The product C60(FeCl3)2 formed with Cl2 gas in the sample preparation was a black insulating powder inside and outside the dry box. Infrared (IR) spectroscopy showed that, when C60(FeCl3)2 is exposed to air, FeCl3 leaves the sample and C60 remains. Coherent (Bragg) X-ray diffraction was not observed from C60(FeCl3)2 although polycrystalline C60 was used in the reaction. For the product from the reaction between C60 and FeCl3 without Cl2 gas, only very weak IR absorption lines from C–Cl bonding were observed, and the X-ray diffraction pattern showed FeCl3 and C60 peaks. This shows that C60 does not react well with FeCl3 without Cl2 gas in the sample preparation. Thus, Cl2 gas enhances the reaction between C60 and FeCl3, produces a noncrystalline product, and is not responsible for the conductivity in chlorinated C60 compounds.