Perfect cubic La-doped boron clusters La&[La@B] as the embryos of low-dimensional lanthanide boride nanomaterials.

La-doped boron nanoclusters have received considerable attention due to their unique structures and bonding. Inspired by recent experimental observations of the inverse sandwich LaB (1) and triple-decker LaB (2) and based on extensive global searches and first-principles theory investigations, we present herein the possibility of the perfect cubic La-doped boron clusters La&[La@B] (3, A) and La&[La@B] (4, A) which appear to be the embryos of the metallic one-dimensional LaB (5) nanowire, two-dimensional LaB (6) nanosheet, and three-dimensional LaB (7) nanocrystal, facilitating a bottom-up approach to build cubic lanthanide boride nanostructures from gas-phase clusters. Detailed molecular orbital and bonding analyses indicate that effective (d-p)σ, (d-p)π and (d-p)δ covalent coordination interactions exist in La&[La@B] (3/4) clusters, while the 1D LaB (5), 2D LaB (6), and 3D LaB (7) crystals exhibit mainly electrostatic interactions between the trivalent La centers and cubic B frameworks, with weak but discernible coordination contributions from La (5d) ← B (2p) back-donations. The IR and Raman spectra of La&[La@B] (3/4) and band structures of LaB (5) and LaB (6) are computationally simulated to facilitate their future characterizations.