The 2D-to-3D geometry hopping in small boron clusters: The charge effect

- The 2D-3D relative energy of small boron cluster (Bn, n = 20-24) linearly varies with respect to the actual net charge.
- Electron addition favors 2D planar structures.
- An early 2D-to-3D geometry hopping occurs for cationic boron clusters, and reversely for anions.
- Planarization of molecular skeleton is a driving force facilitating electron delocalization in 2D structures.