Comments on tables of magnetic space groups

Litvin [Acta Cryst. (2008), A64, 419-424 and supplementary material] extends much of the information contained in Volume A of International Tables for Crystallography for the 230 space-group types to the 1651 types of Shubnikov space groups, using Opechowski-Guccione (OG) notation for the space groups with a black-white lattice. It is pointed out that OG notation has crucial disadvantages compared to Belov-Neronova-Smirnova (BNS) notation. It is shown how Litvin's diagrams of symmetry elements for the orthorhombic Shubnikov space groups can be interpreted in terms of BNS symbols and how those containing e-glides can be simplified. A number of mistakes in the diagrams of Litvin are corrected.