NANOCRYSTALLINE DOMAINS OF A MONOCLINIC MODIFICATION OF BENZENE STABILIZED IN A CRYSTALLINE MATRIX OF C60

The crystal structure of C60.4C6H6 at 104 K has been refined to R(Abso lute value of F) = 0.070, wR(Absolute value of F) = 0.03 The C60 molec ules are arranged in infinite stacks which form a regular, honeycomb-l ike arrangement, whose voids (channels) are filled by benzene molecule s. Contrary to earlier assertions, the C60 molecules form a defective and distorted cubic closest packing in which one C60 out of three is r eplaced by eight benzene molecules. The positions and orientations of the benzene molecules in each channel suggest a hitherto unobserved mo noclinic packing of benzene molecules. The crystal structure may be co nsidered as a macroscopically ordered nanocomposite of fullerene and b enzene domains. Some of the properties of the benzene domains are typi cal of the nanocrystalline state of matter.