Crystal Structures and Phase Transitions of Fullerenes

Abstract

Fullerenes, a new allotrope of carbon, are hollow spherical all carbon molecules composed of six-membered and five-membered rings. Structural studies on C60 and C70 in the solid state at ambient and high pressure are reviewed Phase transitions under high pressures are associated with molecular rotation, orientational ordering, polymerization, and/or crushing of molecules. Tentative p-T phase diagrams for solid C60 and C70 are given. Under appropriate pressure and temperatures, fulleren es in the solid state transform to polymers and diamond. Bulk moduli at low pressures (≤1GPa) are also summarized. © 1995, The Japan Society of High Pressure Science and Technology. All rights reserved.