Be₂B₆ and Be₂B₇⁺ clusters adopt interesting inverse sandwich structures with double σ/π aromaticity, and the former possesses the smallest monocyclic boron ring motif.

Boron-based ternary Rb₆Be₂B₆ cluster features a naked hexagonal boron ring and unique “Big Mac” sandwich shape, being stabilized collectively by four-fold 2σ/6π/6σ/2σ aromaticity.

Boron-based B ₆ Ca ₂ and B ₈ Ca ₂ clusters adopt unique inverse sandwich architectures, which are stabilized by interesting conflicting aromaticity and double aromaticity, respectively.

Two isoenergetic isomers of the Be ₃ B ₁₁ ⁻ cluster, featuring the smallest trihedral spherical geometries, can interconvert via the mechanism of “triangle-pyramid-triangle”, which facilitates the migration of boron atoms in the B ₁₁ skeleton.

Planar hypercoordinate fluorine is elusive due to the high electronegativity of fluorine, which restricts electron delocalization. Despite some progress, planar tetracoordinate fluorine (ptF) anionic species with simple components suitable for photoelectron spectroscopy have not yet been reported. Herein, we introduce the first binary mono-anionic Li4F4− cluster containing a ptF center with C2v symmetry. At a given level of theory, it is a global minimum (GM) structure with good dynamic stability and significant barriers to interconversion into the lowest energy isomers. It is noteworthy that the GM of the neutral Li4F4 species adopts a cube configuration similar to that of the typical bulk lithium fluoride crystal structure rather than a planar shape. The stability of the ptF is dominated by electrostatic interactions, supplemented by a weak covalent component rather than any aromaticity. The cluster is a highly viable species and a promising candidate for experimental detection and characterization.