Cluster Self-Organization of Intermetallic Systems: Two-Layer Quasi-Spherical Nanocluster Precursors K69 and K26 in the Crystal Structure of Li26Na58Ba38 (cF488)

Abstract

The geometric and topological analysis of the crystal structure of intermetallic Li26Na58Ba38 (cF488, a = 27.335 A, V = 20 424 A3, F-43m) is carried out using computer methods (ToposPro software package). The analysis method is based on determining the chemical composition and structure of an intermetallic cluster precursor and constructing a basic 3D network of the structure in the form of a graph whose nodes correspond to the position of their centers of gravity. Using the method of the complete decomposition of the 3D factor graph of the crystal structure into cluster substructures, we find two types of framework-forming nanoclusters, namely, K69 of the 1@16@52 composition and K26 of the 0@4@22 composition with point symmetry g =–43m. The symmetric and topological code of self-assembly of 3D structures from nanocluster precursors is reconstructed in the following form: primary chain → microlayer → microframework. Clusters Ba5, Na6(Na4), and Na2В are determined as spacers occupying voids in the 3D framework of nanoclusters K69 and K26.