The electronic structure and stabilization energy of spherical and pyramidal shapes of boron oxide nanocapsules (X@B 20 O 30 , X=He, Ne, Ar, H, N, Cl) were investigated by long-range and dispersion corrected density functional theory (DFT+Disp) including CAM-B3LYP, B3LYP-D3, ωB97X-D and B2PLYP-D methods. Based on these calculations, the formation of nanocapsules is an exothermic process (except for Cl@B 20 O 30 ). The spherical boron oxide nanocapsules are mainly stabilized by dispersion, while the stability of pyramidal complexes is mainly due to monomer relaxation energy. The theoretical results obtained in this work show that the boron oxide capsule is a good potential candidate for gas storage.