Cluster Self-Organization of Intermetallic Systems: New Clusters-Precursors K15, K11, and K6 for the Self-Assembly of the Yb72Sn46-tP118 Crystal Structure

Abstract

The combinatorial-topological analysis and self-assembly of crystal structures of Yb₇₂Sn₄₆-tP118 (a = 11.076 Å, c = 36.933 Å, V = 4530.86 ų, pr. group P4/mbm) intermetallic compounds is modeled using computer methods (the ToposPro software program). For the crystal structure of Yb₇₂Sn₄₆-tP118, 195 variants of a cluster representation of a 3D atomic grid with 5 (24 variants), 6 (86 variants), and 7 (85 variants) structural units are established. The variant of the fastest self-assembly involving three types of clusters-precursors forming layers of octahedra K6 = 0@6(Yb₄Sn₂) with symmetry g = 4/m, from polyhedra K11 = Sn@10(Yb₈Sn₂) with symmetry g = –1, and polyhedra K15 = Yb@14(Yb₁₀Sn₄) with symmetry g = 2 mm, as well as Yb and Sn spacer atoms, is considered. The symmetry and topological code of the processes of the self-assembly of 3D structures from clusters-precursors are reconstructed in the following form: primary chain → layer → framework.