The Symmetric and Topological Code of the Cluster Self-Assembly of the Crystal Structure of ε-Mg23Al30 of K63 Nanoclusters

Abstract

The geometrical and topological analysis of the crystal structure of intermetallide e-Mg23Al30 (ToposPro program) with V = 3098.0 A3 and space group R-3 is carried out. The symmetric and topological codes of the cluster self-assembly of the crystal structure are determined: primary chain S 3 1 → microlayer S 3 2 → microframework S 3 3 . A new type of nanocluster-precursor of the crystal structure, which is formed on the internal 13-atomic cluster, which represents a template and consists of two bound ridged rings Mg–Al–Mg–Al–Mg–Al with the central Mg atom, is discovered. A quasi-spherical deltahedron shell made from 50 atoms is formed on the template. The center of a K63 cluster occupies the position with the point symmetry 3 in the unit cell. There are six neighboring K63 clusters in the local environment of the K63 cluster in the layer. The basic 3D network, which characterizes the location of the gravity centers of the K63 clusters, corresponds to a hexagonal closely packed network (HCP, Mg type) with CN = 12. The localization of two Mg atoms in the pores of the framework is determined.