The Structure of Fullerite C60 Intercalated with Molecular Oxygen

A (O-2)(x)C-60 sample with a high content of oxygen (x >= 0.4) and free of technological solvent impurities was obtained by precipitation from solution. For the first time, the results of the determination of the x coefficients using C-13 NMR and elemental analysis were compared. It was shown by Raman spectroscopy, mass spectrometry, and NMR that the inclusion of oxygen into fullerite was accompanied by a decrease in the frequency of O-O stretching vibrations by no less than 12 cm(-1) compared with gaseous O-2. Nevertheless, oxygen exists in the molecular form in (O-2)(0.4)C-60 and is released in the form of O-2 as the sample is heated to 373 K. The number of oxygen molecules occupying octahedral pores closets to the fullerene molecule takes on all the possible values, from 0 to 6. At room temperature, the (O-2)(x)C-60 sample lost oxygen much more slowly than similar products prepared by diffusion saturation of pure fullerite with oxygen.