Figure 1
Arrangement of molecules within the crystallographic unit cell. The asymmetric unit is shown in colour (chains A, B, C and D); dimers are formed by chains AB and CD. Vertical black lines indicate the intra-dimer twofold symmetry axes, and the second twofold-symmetry axis, relating chains A and D, is indicated in the centre of the asymmetric unit, almost parallel to the a axis of the unit cell. |