Boron monoxide dimer as a building block for boroxine based buckyballs and related cages: a theoretical study

B3LYP/DZP level calculations are used to predict B₂O₂ cage oligomers, which are constructed from polyhedra by locating their B-B bonds at edge midpoints and three oxygen atoms at each degree 3 vertex. The stability of such cage oligomers depends highly on the B_2nO_n (n = 3, 4, 5) cavities corresponding to the polyhedral faces. All such polyhedral oligomers are found to have larger cohesive energies (E_c's) than corresponding planar structures, except for the smallest (B₂O₂)₆ tetrahedron with extremely high strain arising from the four B₆O₃ cavities forming the tetrahedron faces. Promising (B₂O₂)_n cages with the highest cohesive energies include pentagonal dodecahedral (B₂O₂)₃₀ (c-B30) with B₁₀O₅ cavities, truncated octahedral (B₂O₂)₃₆ (t-B36-2) with B₈O₄ cavities, and truncated icosahedral (B₂O₂)₉₀ (t-B90) with B₁₀O₅ cavities. However, smaller (B₂O₂)_n oligomers are also expected to exhibit cage structures having B₈O₄ or even B₆O₃ cavities because of their large E_c(s).