Cluster Self-Organization of Intermetallic Systems: 0@12(Ga12)@24(Na12Ga12)@72(Rb4Na8Ga60) 108-Atom Three-Layer Icosahedral Cluster and 0@12(Ga12)@32(Na20Ga12) 44-Atom Two-Layer Icosahedral Cluster for Rb24Na200Ga696-oF920 Crystal Structure Self-Assembly

Abstract

The combinatorial-topological analysis and simulation of the self-assembly of the Rb₂₄Na₂₀₀Ga₆₉₆-oF920 (space group Fmmm, V = 17 837 ų) crystal structure are conducted by the computer-based methods (TOPOS program package). The number of options for the cluster representation of the 3D atomic framework with the number of structural units ranging from 4 to 12 came to 9565 variants. Two framework-forming icosahedral clusters—ico-K108 and ico-K44—are determined. The ico-K108 three-layer 108-atom nanocluster has the 0@12(Ga₁₂)@24(Na₁₂Ga₁₂)@72(Rb₄Na₈Ga₆₀) chemical composition of shells, a diameter of 17 Å, and symmetry g = mmm. The ico-K44 two-layer 44-atom nanocluster has the 0@12(Ga₁₂)@32(Na₂₀Ga₁₂) chemical composition of shells, a diameter of 11 Å, and symmetry g = 2/m. The symmetry and topological codes of the Rb₂₄Na₂₀₀Ga₆₉₆–oF920 3D structure’s self-assembly processes from the iсo-K108 and ico-K44 nanocluster precursors are reconstructed in the form primary chain → microlayer → microframework. The Rb spacer atoms and related groups of Ga atoms in the form of chains are located in the large voids of the 3D framework.