According to Fig. 3, the ĪS(r) results suggest that the activation of adjacent carbon/boron sites are quite localized for each tube. Such a localized effect upon reactivity is consistent with what was found earlier in the case of the Stone–Wales defectcontaining [68] and chlorinated (5,5) armchair single-walled CNT [69].To examine the regioselectivity and site ranking ability of ĪS,min, interaction energies for the addition of a hydrogen atom at different carbon sites of the pristine BC3NT are calculated.