These positive outer surfaces are due to the electronic charge withdrawn from hydrogen by carbon atoms. We note that, there are also weak positive regions above boron atoms. These VS,max represent attractive channels for the approach of a nucleophile to the surface of a zigzag BC3NT. The value of Π, our estimate of the internal charge separation, is calculated to be 7.0 kcal/mol, which is in good agreement with reported value for pristine (5,5) and (6,1) CNTs [54,66,67].