RESUMEN
A dielectric study of the structural phase transition from cubic fcc ([Formula: see text]) to simple cubic sc [Formula: see text] at T = 260 K in a fullerene C(60) monocrystal as well as the influence of absorbed oxygen on T(c) are presented. For the first time the results of dielectric measurements of a C(60) monocrystal without any oxygen trapped inside showed a typical first order structural phase transition. It has been shown that absorbed oxygen affects the mechanism of the structural phase transition at T(c) = 260 K in the C(60) single crystal. In the cooling run, the electric permittivity ε' in the vicinity of phase transition decreases for the oxygen free C(60) monocrystal whereas it increases for the C(60) crystal exposed to oxygen.