Solid state chemical transformations of fullerene C-60 as a function of pressure and temperature

Carbon states, products of solid state chemical transformations of fullerite C-60 at pressures up to 10.0 GPa and temperatures up to 1900 K, have been investigated by X-ray diffraction, Raman spectroscopy and atomic force microscopy. P,T-diagram of the formation of atomic, molecular and polymolecular carbon. structures in the conditions of quasi-hydrostatic contraction was determined. It is shown that, along with polymerization, one more type of chemical interaction between C-60 molecules named polycondensation takes place in the system in the area of thermal stability of C-60. The polycondensation of C-60 gives rise to the formation of a new polymolecular type of carbon structures with the shortest intermolecular distance of 0.65 nm. The three-dimensional polycondensation of C-60 is used for the explanation of the nature of ''special'' physical and mechanical properties, including ultrahardness, of this new type of carbon materials.