Superatom–atom super-bonding in metallic clusters: a new look to the mystery of an Au₂₀ pyramid

Abstract

Using the super valence bond model, a generalized chemical picture for the electronic shells of an Au20 pyramid is given. It is found that Au20 can be viewed to be a superatomic molecule, of which its superatomic 16c-16e core (T) is in D(3)S hybridization bonded with four vertical Au atoms for the molecule-like (TAu4) electronic shell-closure. Based on such a superatom-atom bonding model, TX4 (X = F, Cl, or Br) are predicted to be very stable. Such a superatom-atom T-Au/T-X bonding enriches the scope of chemistry.

Behaviour of ‘free-standing’ hollow Au nanocages at finite temperatures: a BOMD study

“…It is further established from the above as well as the ensuing research reports that as a consequence of strong relativistic effects anionic gold nanocages evolve from 'Flat Gold Cages' (Au 13 − , Au 14 − and Au 15 − ) to HGCs (Au 16 − , Au 17 − and Au 18 − ) and 'Tetrahedral Gold Cages' (Au 19 − and Au 20 − ) [11][12][13][14][15][16]. Similar studies on neutral gold clusters followed later [17][18][19][20][21] demonstrating a flat-to-HGC transition at Au 17 as compared to Au 16 in anionic clusters [17]. Studies on cationic Au n (n > 10) are relatively very few as compared to their neutral and anionic counterparts [16].…”

D6h‐Au42 Isomer: A Golden Aromatic Toroid Involving Superatomic π‐Orbitals that Follow the Hückel (4n+2)π rule

“…For example, some ligand‐protected gold clusters displaying a single superatomic bond involving two cluster cores have been proposed as superatomic analogues of diatomic molecules . Also, we and other groups explored the occurrence of hybridization in superatoms leading to hybridized superatomic orbitals, resulting in similar multicenter bonds in a symmetric spatial disposition, which adds to the observed single, double and triple superatomic bonds in the gold clusters. Thus, the superatom concept is intimately connected to relevant tools of great chemical significance, such as the Lewis structure model and the VSEPR theory …”

Computational studies of stable hexanuclear CulAgmAun(l + m + n = 6;l,m,n > 0) clusters

“…As for the Quantum Chemistry (QC) methods and combined schemes (EP and QC in tandem), they allow limited PES searches for small clusters mainly because of the demanding convergence process involved in the quantum mechanical solution of the multi‐electron problem. Nevertheless QC approaches have revealed the existence of unexpected structures in pure or bimetallic clusters …”

“…Nevertheless QC approaches have revealed the existence of unexpected structures in pure or bimetallic clusters. [28][29][30] Earlier studies on coinage metal (Cu, Ag, and Au) clusters were performed using EP to analyze a variety of properties, for example, thermodynamic properties of small clusters, [21,31,32] and more recently, larger noble metal nanoparticles have been the subject of extensive computations regarding their thermal stability and structural changes. [33] Despite the relatively good description of atomic bonding provided by empirical potentials, the electronic contribution is taken into account only implicitly in the parameter set of each EP.…”