Single-Crystal Structural Study of fcc and hcp C₆₀ from 107 to 298 K Using Synchrotron X-Rays

Abstract

The crystal structure of pure C 60 has been determined by means of single-crystal diffraction methods using synchrotron X-rays at room and below room temperatures. Both fcc and hcp single crystals were found in one-run product by means of the precession method and a four-circle diffractometer. The fcc phase at 266 K gave the best fit for a shell model with the fullerene radius r =3.52 Å. The radius did not change significantly at lower temperatures but deviation from the free rotation model was detected for smaller B iso and larger R values. The least-squares calculation for the hcp phase converged at (1/3, 2/3, 0.459) for the one-sided fullerene, suggesting that solvent residue may remain in the crystal.