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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
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Octagonal symmetry in low-discrepancy β-manganese
Wolfgang Hornfeck1, Philipp Kuhn1
1Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft- und Raumfahrt (DLR), 51170 Köln, Germany.
Acta Crystallographica. Section A, Foundations and Advances
|September 2, 2014
Summary
A novel cubic variant of beta-manganese (β-Mn) displays local octagonal symmetry. This structure is nearly optimal for minimizing geometrical discrepancy and maximizing interatomic distances, offering insights into structural chemistry.
Area of Science:
- Crystallography
- Materials Science
- Solid-State Chemistry
Background:
- Beta-manganese (β-Mn) is a complex cubic structure.
- Understanding structural variations is key to materials properties.
Purpose of the Study:
- To present a low-discrepancy cubic variant of β-Mn.
- To analyze its structural features and optimality.
- To introduce geometrical discrepancy maps for structural analysis.
Main Methods:
- Derivation of ideal structural parameters for the P4132 enantiomorph.
- Calculation of geometrical star discrepancy (D(*)) and minimal interatomic distance (dmin) maps.
- Comparison of actual and ideal β-Mn structure models.
Main Results:
- A β-Mn variant with local octagonal symmetry along <100> axes was identified.
- The 'octagonal' variant demonstrates near-optimal minimization of D(*) and maximization of dmin.
- Geometrical discrepancy maps were calculated over a range of generalized β-Mn structures.
Conclusions:
- The identified 'octagonal' β-Mn variant represents a near-optimal structure.
- Geometrical discrepancy maps are powerful tools for structural chemistry.
- This approach can predict and discriminate between structural models.
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