The striking presence of concave angles in a morphology normally associated with twinning motivated us to rigorously assess the crystals' intensity distribution and symmetry in order to exclude the possible presence of merohedral twinning phenomena. In that case of merohedral twinning, the reflections of the domains overlap and, as a consequence, the shape of the diffraction pattern appears to indicate single crystallinity. The diffraction data of merohedral crystals should exhibit: (i) a deviation from the expected intensity distribution and (ii) a symmetry higher than that of the true Laue symmetry. We excluded merohedral twinning using the following tests: (i) We assessed the average intensity distribution values, <|E 2 -1|>, obtained from the intensities of the diffractions (~0.8), which indicated the formation of non-centrosymmetric structures, in line with the crystal structure determinations. For twinned crystals, a much lower value is expected (~0.2). Furthermore, the cumulative intensity distribution plots are also in good agreement with non-centrosymmetric, single crystals (Figures and). (ii) We examined the symmetry of the crystals. Due to the exact super positioning of diffraction patterns, merohedral twinning mimics a higher symmetry, which leads to a higher Laue class. Merohedral twinning occurs in hexagonal and other crystal systems that have more than one Laue class. Our structural determinations indicated a hexagonal system with the point group 6/mmm and the space group P622. The point group of these crystals is expressed in the higher symmetry Laue class 6/mmm. A comparison of all the calculated Rint values of the possible Laue groups showed that the assigned symmetry and space group is correct (Figures and).