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 Crys tallography (1952), Vol. 1. (Birmingham: Kynoch Press). This volume ha s been replaced by International Tables for Crystallography (1983), Vo l. A (Dordrecht: Kluwer Academic Publishers), where changes have been made in these printed coordinate triplets of the general positions. Th e use of the original Opechowski-Guccione symbols with this latter vol ume leads to misinterpretations and ambiguities. In this paper, all ca ses where the changes in the printed coordinate triplets of the genera l 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 t he notation for the two cubic crystal classes <m(3)over bar> and m(3) over barm$, which now contain the symbol 3 instead of 3, and the conse quences of the introduction of the symbol e into the symbols for space groups are discussed.