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The crystallographic chameleon: when space groups change skin.
Massimo Nespolo1, Mois I Aroyo2
1Université de Lorraine, CRM2, UMR 7036, Vandoeuvre-lès-Nancy 54500, and CNRS, CRM2, UMR 7036 Vandoeuvre-lès-Nancy 54506, France.
Acta Crystallographica. Section A, Foundations and Advances
|September 1, 2016
Summary
This study provides a guide to alternative space group settings, crucial for understanding crystal structures and their relationships. It highlights settings not fully detailed in standard references for advanced crystallographic analysis.
Area of Science:
- Crystallography
- Materials Science
- Solid-State Chemistry
Background:
- International Tables for Crystallography, Volume A, is a primary reference for space-group data.
- This reference is not exhaustive, as many space groups have multiple settings not fully described.
Purpose of the Study:
- To provide a guide for expressing symmetry operations, Hermann-Mauguin symbols, and Wyckoff positions in alternative space group settings.
- To identify and present alternative space group settings with practical applications that are not listed in Volume A.
Main Methods:
- Systematic analysis of space group symmetry operations.
- Comparison and tabulation of Hermann-Mauguin symbols and Wyckoff positions across different settings.
- Literature review to identify and document underrepresented alternative settings.
Main Results:
- A comprehensive guide for translating crystallographic data into alternative settings.
- Identification of specific space groups with important, yet unlisted, alternative settings.
- Demonstration of the utility of alternative settings in analyzing polymorphs, derivative structures, pseudo-symmetry, and twin substructures.
Conclusions:
- Alternative space group settings are essential for advanced crystallographic investigations beyond basic structure description.
- The presented guide and identified settings enhance the utility of crystallographic databases and analysis tools.
- Further exploration of alternative settings can reveal new insights into complex crystal structures and their relationships.
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