B26−: The smallest planar boron cluster with a hexagonal vacancy and a complicated potential landscape

B33– and B34–: Aromatic Planar Boron Clusters with a Hexagonal Vacancy

“…It should be noted that the hexagonal vacancy, essential for the stability of borophenes, is the most important structural feature in mid‐sized boron clusters, starting from B 26 – . The role of the hexagonal vacancy in the stability of B 36 has been further analyzed recently .…”

“…Early theoretical studies suggested that the B 12 icosahedral unit prevalent in bulk boron is not stable as isolated clusters relative to planar or quasi‐planar (2D) structures . Over the past decade, joint experimental and theoretical investigations have uncovered a rich 2D world for size‐selected boron clusters . Ion mobility measurements in combination with density functional theory (DFT) calculations suggested that cationic B n + clusters have 2D structures up to n = 16 .…”

Stable global tubular boron clusters in Na2B18 and Na2B18−

“…5 For anionic boron clusters, planar or quasiplanar boron (2D) forms remain critical competing alternatives that are more stable in energy than the tubular forms; this has been conrmed via photoelectron spectroscopy (PES) combined with theoretical investigations. [26][27][28] The 2D preference of negatively charged boron clusters can be ascribed to the fact that electron addition tends to enhance the stability of the 2D form over the corresponding 3D isomer, irrespective of the available electrons. 29 For instance, as shown in Scheme 1, the tubular structure of B 18 + was suggested to be the global minimum, whereas the B 18 , B 18 À and B 18 2À analogues were found to be high-energy isomers.…”

TGMin: An efficient global minimum searching program for free and surface‐supported clusters

“…Until now, several global optimization programs based on the BH algorithm, in conjunction with density functional theory (DFT), tight‐binding DFT (DFTB), or (semi‐) empirical methods have been proposed . Tsinghua Global Minimum (TGMin), developed in 2011, is one of the most successful BH program as TGMin has already helped researchers identify tens of new clusters, including the hexagonal B 36 − cluster, the all‐boron borophenes and borospherenes B 40 − , B 26 − , B 28 − , B 30 − , B 35 − , B 39 − , metallo‐ borophenes, ‐borospherenes, and ‐nanotubes CoB 18 − , MnB 16 − , RhB 18 − , TaB 20 − , as well as the PrB 7 − , LnB 8 Ln (Ln = La, Pr) sandwich complexes, and others . TGMin was also used to identify atmospheric aerosol clusters and surface‐adsorbed species .…”