International
Tables for
Crystallography
Volume A
Space-group symmetry
Edited by Th. Hahn

International Tables for Crystallography (2006). Vol. A, ch. 9.1, p. 743

Section 9.1.5. Remarks

H. Burzlaffa and H. Zimmermannb*

aUniversität Erlangen–Nürnberg, Robert-Koch-Strasse 4a, D-91080 Uttenreuth, Germany, and bInstitut für Angewandte Physik, Lehrstuhl für Kristallographie und Strukturphysik, Universität Erlangen–Nürnberg, Bismarckstrasse 10, D-91054 Erlangen, Germany
Correspondence e-mail:  helmuth.zimmermann@knot.uni-erlangen.de

9.1.5. Remarks

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  • (i) For the handling of special problems such as subgroup relations, it may be convenient to use additional centred cells, e.g. a hexagonal cell centred at [2/3,1/3,0] and [1/3,2/3,0,] which is called H. In this case, rule (iiia[link]) above is violated as vectors a and b are now directed along the second set of twofold axes. Similarly, for tetragonal lattices, C may be used instead of P, or F instead of I; cf. Chapter 1.2[link] .

  • (ii) Readers who have studied Section 8.1.4[link] may realize that the `lattice bases' defined here are called `primitive bases' there and that both `primitive bases' and `conventional bases' are special cases of bases used in crystallography.








































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