Particularities of C-60 transformations at 1.5 GPa

The high-pressure states of C-60 fullerene corresponding to the 1.5 GPa iso baric section of its p,T diagram in the 293-1073 K temperature range were i nvestigated by X-ray diffraction and IR and Raman spectroscopies. It was sh own that increasing the treatment temperature of C-60 at quasihydrostatic p ressure changes the nature of the polymerization products. The IR and Raman spectra of the high-pressure materials obtained at 423 K are similar to th e spectra of the dumb-bell-shaped C60 dimer synthesized in a solid-state me chanochemical reaction of C60 With potassium cyanide by Wang et al.(1) It c an be concluded that this dumb-bell-shaped dimer is the main structural uni t forming the low-pressure polymerization product. So, on further temperatu re increase, the dimer phase becomes unstable and transforms into the "low- pressure" orthorhombic polymerized phase of C60 which, in turn, transforms into the tetragonal polymerized phase at temperatures above similar to 723 K. Depolymerization of the polymerized phases at temperatures above similar to 900 K results in the formation of the monomeric fee phase of C60 fuller ene, which agrees with the experimental data determined previously by Bashk in et al.(2).