Theoretical analysis of formation energy and geometry was done to compare the relative stabilities of modified carbon nanostructures representative fragments. Structure and energies of formation were calculated at semiempirical level of theory. Depending of B-N pair localization on the molecular structures the formation enthalpy decreases. B-N substitution in tubular structures at low concentration decreases the energy when the tubes have small diameters. Our results are in according to experimental works which have shown that boron and nitrogen are met at region of defects in B X C Y N Z nanostructures.
nanostructures; semiempirical methods; doping; boron; nitrogen
