Does carbon prefer flat or curved surfaces?

The presence of fullerene- and nanotube-like elements in carbons prepared f rom saccharose and anthracene by slow pyrolysis and then heat treated at 10 00 degreesC, 1900 degreesC, and 2300 degreesC has been revealed using Raman spectroscopy. High energy X-ray diffraction has been used to examine the e ffect on these carbons of heat treatment. Tendency to graphitization of the anthracene-based carbon and resistance to graphitization of the saccharose carbon will be considered in the light of the formation of curved graphiti c networks and cages. The obtained results lead us to propose a model of th e structure of non-graphitizing and graphitizing carbons.