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ELFs of single bond (Zn 4 ) 2 2+ , double bond (Zn 4 ) 2 4+ (singlet and triplet) and triple bond (Zn 4 ) 2 6+ compared with Ne 2 , F 2 , O 2 (singlet and triplet), and N 2 in color and shape. The scale is labeled aside.
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Metal clusters with specific number of valence electrons are described as superatoms. Super valence bond (SVB) model points out that superatoms could form the superatomic molecules through SVBs by sharing nucleus and electrons. The existence of superatom-superatom bonding was verified by the shape of their orbitals in former studies. In this paper,...
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Using the evolutionary algorithm USPEX and DFT+U calculations, we predicted a high‐symmetry geometric structure of the bare Ti8O12 cluster composed of 8 Ti atoms forming a cube, in which O atoms are at midpoints of all of its edges, in excellent agreement with experimental results. Using natural bond orbital analysis, adaptive natural density parti...
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Intercluster bonding features are relevant to bringing building blocks on the road to molecularly conceived materials in a rational fashion. Such characteristics have been developed for coinage metal clusters resembling...
Envisaging cluster-based materials following a controlled aggregation of discrete clusters via intercluster bonding is relevant for achieving the realms of bulk matter from the molecular scale. In this sense, the rational usage of building blocks into the realization of well-structured cluster-based materials remains a relevant issue in the current completion of molecular cluster materials. This chapter exposes recent addition to the understanding of intercluster aggregation of different building blocks based on gold- and Zintl-ion clusters. Here, we provided relevant examples exposing the interesting bonding characteristics enabling strong cluster-cluster bonding. Such aspects follow classical chemistry concepts related to chemical bonding, allowing single, double, and higher bond orders to the chemical understanding of cluster-based materials. Hence, classical concepts widely employed for simple molecules are able to be applied in the rationalization of different species.
The plasmonic properties of tetrahedral aluminum nanoparticles have been investigated using time‐dependent functional theory (TDDFT) calculations. The excitation energies are calculated for tetrahedral aluminum nanoparticles (Aln, n = 10–120) with different charge states. The BP86/DZ model is used to perform geometric optimization calculations for these clusters. The SAOP/DZ and LB94/DZ levels of theory have been used for the excitation energy calculations of these tetrahedral aluminum clusters. The absorption peaks are red‐shifted upon increasing the size of the aluminum nanoparticles.
Metal organic framework (MOF) materials have attracted significant attention due to their wide potential applications, but it is still a challenge to design MOFs with advanced properties by exploring novel metal nodes. In this study, a kind of superatom organic framework (SOF) material is proposed based on the superatom network (SAN) model. Tetrahedron Al4 superatom unit is used as nodes in the MOF structure, and linear -CC- ligands are chosen as linkers. Localized chemical bonding analysis and nucleus-independent chemical shift (NICS) scan confirm that the Al4 core keeps the superatom electronic shell in the SOF structure. Further calculations demonstrate that this Al4C4 crystal has high dynamic and thermal stabilities, with an indirect semiconductor band gap of 2.57 eV. Analysis of its optical properties indicates its potential applications as an optoelectronic device. This novel kind of SOF material has both porous framework as traditional MOFs and superatomic character in its nodes, indicating its unique potential properties. Our work would provide a new way for designing functional MOF materials.
Evolutionary searches using the USPEX method (Universal Structure Predictor: Evolutionary Xtallography) combined with density functional theory (DFT) calculations were performed to obtain the global minimum structures of beryllium (Ben, n=3-25)...
Ligand-protected gold clusters are usually understood in terms of the superatom concept, where certain species are able to behaves as prototypical molecules. Here, we discuss the metalloid cluster Au70S20(PPh3)12 in terms of the bonding characteristics of its inner 18-cluster electron Au224+ core. Our interpretation is based on a SP3-hybridized core involving four fused Au6 units denoting four equivalent hybridized localized orbitals, with the remaining electrons from the 1D10 state remaining as formally non-bonding orbitals. Such characteristics expose a rationalization of Au70S20(PPh3)1 as a superatomic analog for a transition metal complex, following the 18-electron rule, mimicking the classical bonding picture of the tetrahedral Ni(CO)4 complex. The Au22 core as an aggregate of Au6 units encourages the search for further examples of SP3-cluster nodes precluding larger aggregates, contributing to the design opportunities of functional clusters and nanoparticles.
The thermal history of melts leads to three liquid states above the melting temperatures Tm containing clusters—bound colloids with two opposite values of enthalpy +Δεlg × ΔHm and −Δεlg × ΔHm and zero. All colloid bonds disconnect at Tn+ > Tm and give rise in congruent materials, through a first-order transition at TLL = Tn+, forming a homogeneous liquid, containing tiny superatoms, built by short-range order. In non-congruent materials, (Tn+) and (TLL) are separated, Tn+ being the temperature of a second order and TLL the temperature of a first-order phase transition. (Tn+) and (TLL) are predicted from the knowledge of solidus and liquidus temperatures using non-classical homogenous nucleation. The first-order transition at TLL gives rise by cooling to a new liquid state containing colloids. Each colloid is a superatom, melted by homogeneous disintegration of nuclei instead of surface melting, and with a Gibbs free energy equal to that of a liquid droplet containing the same magic atom number. Internal and external bond number of colloids increases at Tn+ or from Tn+ to Tg. These liquid enthalpies reveal the natural presence of colloid–colloid bonding and antibonding in glass-forming melts. The Mpemba effect and its inverse exist in all melts and is due to the presence of these three liquid states.
The synthesis and application of compounds with Cr-Cr and V-V d-d quintuple bonds (σ, 2π, 2δ) have led to new thinking about whether d-d multiple bonds also exist between early transition metals such as Sc-Sc and Ti-Ti. In this study, by extensive unbiased global search at the density functional theory level, the low-energy structures of 26e and 30e TM2Lin clusters were obtained. Based on the super valence bond (SVB) theory, the prolate double-core structure of TM2Lin clusters was regarded as a superatomic molecule, of which each half was regarded as an open-shell superatom, and the electronic shell-closure was realized by forming multiple bonds between superatoms. Then, the quintuple super bonds (2δ, 2π, σ) of the Li18Ti2, Li20Sc2, [Li17V2]+, [Li17Ti2]- clusters and the triple super bonds (2π, σ) of the Li24Sc2 and Li24Y2 clusters were confirmed via chemical-bonding analysis. This way of forming multiple bonds between early transition metals through superatomic bonding has promoted the experimental synthesis and application of early transition metal multiple bond compounds.
