26 Space group changes and 6 crystallographic puzzles found in Tetrahedron journals

The November 2002 release of the Cambridge Structural Database (CSD) contains unit-cell dimensions and atom coordinates for 121 compounds reported in Tetrahedron family journals under space group P1 (No. 1) and 1170 under space group P21 (No. 4). Twenty six of these compounds have been revised to space groups of higher symmetry. Seven have been originally described in space group P1, 18 in space group P21 and one in a non-standard setting of space group P21. The most common revisions are P1→P1̄, P21→P21/c and P21→P212121. We must add to these 26 compounds four other compounds that has been already re-interpreted in other journals, bringing the total number of P1 and P21 incorrect structures to 30. Thus the percentage of incorrect structures is 2.32%. Evidence favouring higher symmetry is equivocal for four other compounds, thus they are not included among the incorrect structures. Two other structures containing other mistakes are also noted. The consequence of incorrect space group assignment on the molecular structure will be discussed.