Аннотация:Investigation of the orientational ordering phase transition at 260 K in crystalline C-60 was done using differential scanning calorimetry, X-ray diffraction, high performance liquid chromatography and C-13, H-1 nuclear magnetic resonance methods. The smearing over the large temperature range of the first-order transitional peak on differential scanning calorimetry curves due to prolonged mechanical crushing was observed, the structure being crystalline. The temperature dependences of C-13 nuclear spin-lattice relaxation time (T-1) reveal however only the reduction of the T-1 jump without shifting in temperature. From these facts it is transpired that two alternative mechanisms are responsible for grinding-induced changes in the structure of C-60 crystals.