On Opechowski-Guccione Magnetic Space-Group Symbols

The interpretation of Opechowski-Guccione magnetic space-group symbols is based, in part, on the printed coordinate triplets of the general positions of space groups given in International Tables for X-ray Crystallography (1952), Vol. 1. (Birmingham: Kynoch Press). This volume has been replaced by International Tables for Crystallography (1983), Vol. A (Dordrecht: Kluwer Academic Publishers), where changes have been made in these printed coordinate triplets of the general positions. The use of the original Opechowski-Guccione symbols with this latter volume leads to misinterpretations and ambiguities. In this paper, all cases where the changes in the printed coordinate triplets of the general positions have the consequence of changing the meaning of Opechowski-Guccione symbols for magnetic space groups are tabulated. In addition, the changes to magnetic space-group symbols owing to the change in the notation for the two cubic crystal classes m3 and m3m, which now contain the symbol 3 instead of 3, and the consequences of the introduction of the symbol e into the symbols for space groups are discussed.