Analysis of the structural continuity in twinned crystals in terms of pseudo-eigensymmetry of crystallographic orbits.

IUCrJ

Université de Lorraine, Faculté des Sciences et Technologies, Institut Jean Barriol FR 2843, CRM2 UMR CNRS 7036, BP 70239, Boulevard des Aiguillettes, F-54506 Vandoeuvre-lès-Nancy cedex, France.

Published: January 2014

The reticular theory of twinning gives the necessary conditions on the lattice level for the formation of twins. The latter are based on the continuation, more or less approximate, of a substructure through the composition surface. The analysis of this structural continuity can be performed in terms of the eigensymmetry of the crystallographic orbits corresponding to occupied Wyckoff positions in the structure. If [Formula: see text] is the space group of the individual and [Formula: see text] a space group which fixes the twin lattice obtained as an intersection of the space groups of the individuals in their respective orientations, then a structural continuity is obtained if (1) the eigensymmetry of an orbit under [Formula: see text] contains the twin operation; (2) the eigensymmetry of a union of orbits under [Formula: see text] contains the twin operation; (3) the eigensymmetry of a split orbit under [Formula: see text] contains the twin operation; or (4) the eigensymmetry of a union of split orbits under [Formula: see text] contains the twin operation. The case of the twins in melilite is analysed: the (approximate) restoration of some of the orbits explains the formation of these twins.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4104974PMC
http://dx.doi.org/10.1107/S2052252513026493DOI Listing

Publication Analysis

Top Keywords

[formula text]
24
text] twin
16
twin operation
16
structural continuity
12
operation eigensymmetry
12
analysis structural
8
crystallographic orbits
8
formation twins
8
text] space
8
space group
8

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!