Topology of Intermetallic Crystals: Classification, Uniformity, and Transitions

Area of Science:

• Crystallography
• Materials Science
• Computational Chemistry

Background:

• The Inorganic Crystal Structure Database contains extensive data on intermetallic compounds.
• Understanding crystal structures is crucial for materials design and property prediction.
• A systematic classification and analysis of these structures are needed.

Purpose of the Study:

• To classify a large dataset of binary intermetallic compounds based on their crystal structures.
• To develop models for understanding structural transitions and predicting structural robustness.
• To identify common topological types and their prevalence in intermetallic compounds.

Main Methods:

• Analysis of 7551 binary intermetallic compounds using the ToposPro program package.
• Application of a combined geometrical-topological approach, including periodic atomic nets and Voronoi partitions.
• Classification into topological types and estimation of structural uniformity via atomic Voronoi polyhedra.

Main Results:

• Classification of intermetallics into 949 topological types, with 20 types covering 57% of the sample.
• Description of displacive transition mechanisms and identification of the body-centered lattice's role.
• Introduction of a uniformity concept based on Voronoi polyhedra, correlating low uniformity with data errors or directed bonds.

Conclusions:

• The study provides a comprehensive topological classification of binary intermetallic compounds.
• The proposed uniformity criteria can serve as a tool for assessing the reliability and robustness of crystallographic data.
• Understanding structural transitions offers insights into solid-state transformations in intermetallics.