Oxidation of C60 by hexafluorides

Far infrared (FIR) and Raman spectroscopy studies of C-60(ASF(6))(x) and C-60(SbF6)(x) were carried out at room temperature. The FIR spectra showed the presence of AsF6- and SbF6. There was a shift upward of (13 +/- 3) cm(-1) in the tangential A(g) mode compared to that of neutral C-60 This shift is attributed to a reduction in the electron screening of carbon. The charge transfer from C-60 is 0.033 electrons per carbon atom, which is equivalent to two electrons per C-60 molecule. This shows that the oxidation of C-60 in C-60(AsF6)(2) and C-60(SbF6)(2) is the source of the charge on the negative ions. The effect of air exposure on the compounds as indicated by the FIR spectra is also reported.