Comment on Enantiomorphism and multiple-beam X-ray diffraction by Roberto Colella (1994)

For the transition of the structure factors of benzil (B) to benzil (A), Colella [Acta Cryst. (1994), A50, 55-57] employs the relation

i.e., in matrix notation,

This relation is wrong since det (A) = 1. It is not a mapping onto an enantiomorph; for the change of handedness, det (A) must be -1. Moreover, matrix A is an element of the related point group 321. Thus, the result is symmetrically equivalent to the starting set of structure factors. As a consequence, all arguments presented on the basis of (1) are invalid.