Dilute solutions of the C-70 fullerene (at concentrations from 0.0001-0.0005% to a few hundredths of a percent) in benzene, toluene, and p-xylene are investigated using small-angle and wide-angle X-ray diffraction. It is revealed that an increase in the C-70 fullerene concentration leads to a nonmonotonic shift of the small-angle X-ray diffraction patterns along the intensity axis: the intensity first decreases, reaches a minimum, and then increases. The wide-angle X-ray diffraction patterns of all the solutions under investigation exhibit two halos: as the fullerene concentration in the solution increases, the intensity of the first halo increases, whereas the intensity of the second halo decreases. The variations observed in the X-ray diffraction patterns of the fullerene solutions are interpreted in terms of structuring of the solvents, i.e., the formation of a specific order on the molecular and supramolecular levels. The X-ray diffraction data are in good agreement with the nonmonotonic concentration dependences of the density of the fullerene solutions in aromatic solvents. A structural interpretation of the initial decrease in the density of the fullerene solutions is proposed.
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