Double-ring tubular (B₂O₂)_n clusters (n = 6-42) rolled up from the most stable BO double-chain ribbon in boron monoxides

Based on extensive global searches and first-principles theory calculations, we present herein the possibility of double-ring tubular (B₂O₂)_n clusters (n = 6-42) (2-10) rolled up from the most stable one-dimensional (1D) BO double-chain ribbon (1) in boron monoxides. Tubular (3D) (B₂O₂)_n clusters (n ≥ 6) are found to be systematically much more stable than their previously proposed planar (2D) counterparts, with a 2D-3D structural transition at B₁₂O₁₂ (2). Detailed bonding analyses on 3D (B₂O₂)_n clusters (2-10) and their precursor 1D BO double-chain ribbon (1) reveal two delocalized B-O-B 3c-2e π bonds over each edge-sharing B₄O₂ hexagonal unit which form a unique 6c-4e o-bond to help stabilize the systems. The IR, Raman, UV-vis, and photoelectron spectra of the concerned species are computationally simulated to facilitate their experimental characterization.