Carbon framework structures produced in the Fullerene related materials

Soot produced from graphite through arc discharge was separated into four fractions which were structurally analyzed. The toluene-soluble fraction carried C₆₀, C₇₀, and C₇₆-C₁₂₀ fullerenes while the toluene-insoluble quinoline-soluble fraction (ca. 1 wt%) consisted of larger clusters of C₇₀ to C₄₀₀ which have a similar framework to C₆₀ or C₇₀ fullerenes. Graphitic substances in the quinoline-insoluble fraction were separated through precipitation in acetone. Combustion of the quinoline-insoluble fraction free from graphitic substances (15 wt%) revealed two kinds of carbon framework structures; one is a pentagon-containing system similar to fullerenes (ca. 30 wt%) and the other is a rather graphitic, hexagonal system (ca. 45 wt%). The pentagon-containing system in 'soot' particles burned in air at temperatures as low as 400°C and was thermally converted to a hexagonal structure by heat treatment above 800°C.