RECOGNIZING THE (FALSE SYMMETRY) TRICLINIC (AP) TO (TRUE SYMMETRY) CENTERED MONOCLINIC (MC) PATHOLOGY

Some fifty-odd published examples of corrections from (false symmetry) triclinic to (true symmetry) centred monoclinic (aP to mC) are analys ed to see whether the need for correction of symmetry should have been obvious to the original investigators. We conclude that about two-thi rds of the examples were transparent in that special features of the d imensions of the reduced triclinic cell should have aroused the suspic ions of the investigator. For the other third, calculation of the metr ic tensor would have indicated the possibility of symmetry higher than triclinic. However, it should always be remembered that the true symm etry of a crystal is revealed by intensity rather than by metric relat ionships, or by other techniques such as optical microscopy.