The first crystal structure reported in Acta Crystallographica (Clews & Cochran, 1948). (a) Selected intermolecular distances as given in Fig. 5 of the original paper. (b) The same information shown graphically with modern visualization software (Macrae et al., 2006). A simulated powder diffraction pattern calculated by the same program is also shown. (c) checkCIF report on the data provided by the authors. Although the original paper omits many items that would today be regarded as important, there is nothing to suggest significant error in the model.