A more rational order for the 230 space groups.

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Title: A more rational order for the 230 space groups.
Authors: Aroyo, Mois I.1 (AUTHOR) mois.aroyo@gmail.com, Brock, Carolyn Pratt2 (AUTHOR) cpbrock@uky.edu
Source: Journal of Applied Crystallography. Jun2026, Vol. 59 Issue 3, p932-942. 11p.
Subjects: Space groups, Crystallography, College teaching, Crystal structure, Crystal symmetry, Symmetry, Symmetry groups
Abstract: The order of the space groups in International Tables for Crystallography is full of inconsistencies, all of which can be traced back to the order Schoenflies published in 1891. The many inconsistencies obscure the relationships between the space groups and therefore make teaching about them more difficult. A more rational order based on a small number of principles has been developed. The order of the crystal systems and the order of the geometric crystal classes (i.e. the point groups) are unchanged; they have been considered carefully and revised in the past. What is new is that groups within geometric crystal classes are sorted first by arithmetic crystal class (point group plus centering type of the conventional cell) and then by the number and type of symmetry elements for which the defining operations (1) have intrinsic translation parts (i.e. are screw axes or glide planes) and (2) appear in the full Hermann–Mauguin symbol of the space group. While it seems unlikely that the new ordering will replace the current order, it is recommended that it be adopted as an alternative in space‐group studies and in teaching of crystallographic symmetry. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:The order of the space groups in International Tables for Crystallography is full of inconsistencies, all of which can be traced back to the order Schoenflies published in 1891. The many inconsistencies obscure the relationships between the space groups and therefore make teaching about them more difficult. A more rational order based on a small number of principles has been developed. The order of the crystal systems and the order of the geometric crystal classes (i.e. the point groups) are unchanged; they have been considered carefully and revised in the past. What is new is that groups within geometric crystal classes are sorted first by arithmetic crystal class (point group plus centering type of the conventional cell) and then by the number and type of symmetry elements for which the defining operations (1) have intrinsic translation parts (i.e. are screw axes or glide planes) and (2) appear in the full Hermann–Mauguin symbol of the space group. While it seems unlikely that the new ordering will replace the current order, it is recommended that it be adopted as an alternative in space‐group studies and in teaching of crystallographic symmetry. [ABSTRACT FROM AUTHOR]
ISSN:00218898
DOI:10.1107/S1600576726002360