CRYSTAL-STRUCTURE AND DISORDER IN SOLID C-70

Detailed analysis of the room-temperature x-ray powder-diffraction dat a of pure, as-prepared, solid C70 is reported. C70 adopts a hcp struct ure (space group P6(3)/mmc) with a=10.53(1) angstrom and c=17.24(1) an gstrom. Quantitative agreement between the observed and calculated dif fraction patterns require (a) orientational disorder among the molecul es, (b) the presence of approximately 5% of stacking faults, and (c) a fraction of the sample to be either microcrystalline or amorphous.