Phase transformations in solid C 60 at high-pressure-high-temperature treatment and the structure of 3D polymerized fullerites
New data concerning the solid C 60 phase transformations in the pressure-temperature range P = 6.5-13 GPa, T = 300-2100 K and nonhydrostatic conditions are presented and plotted in the P- T coordinates. The structure of superhard and ultrahard carbon phases obtained with these conditions is investigated by X-ray powder diffractometry and Raman scattering. New crystal structures of distorted bcc type and transient to diamond states are revealed in the synthesized samples. Fragments of different lengths of polymerized fullerene cages are found from resonance Raman spectra of the samples obtained at P = 13 GPa and T < 1200 K.