By using the B3LYP/6-31G (d, p) density functional level of theory, the structural and magnetic properties of the BNNT (6,3), C(B)BN6-3, C(N) BNNT (6,3), BNNT (6,3) two caps, C(B) BNNT (6,3) – two caps and C(N) BNNT (6,3) – two caps have been studied. The effects of the substitution of the boron or nitrite atom by carbon atom impurity and closing two- ends of nanotube have been investigated in this study. The substituted atom type and closing two-ends of nanotube type on the value of the MT and the abstract value MT changes from 0.36 μB to 1.055 μB. Also, the Es of the nanotubes indicate the changes between 1.25 eV and 6.11 eV where the smallest and the highest E belong to BN6-3 and C(B) BNNT (6, 3) – two caps. Thus, it seems that the mentioned nanotubes can be used to produce the semiconductors with various band gaps.
