Progress and effectiveness of structural models of carbons

Recent progress of structural models of carbon materials is reviewed by the classification of structures into nano, and mesoscopic views. The graphitic materials are viewed on the basis of the structural units of hexagon plane, graphite crystal, nano, meso, and macroscopic structural units. Novel 3-dimensional models of mesophase pitch based carbon fibers and carbon nanofibers are proposed by the comprehensive results of SEM, STM, and TEM. Graphitizability of carbon materials is also understood by the concept of structural hierarchy - the domain unit of carbon materials as a restricting boundary of the size development of crystallinity. The diversity of carbon materials in terms of their properties, phase, and applications becomes significant by combining the molecular and structural concepts.