Figure 1
The molecular structures of the constituents of the asymmetric unit of (I), showing the atom-labelling scheme and displacement ellipsoids at the 50% probability level. The molecules are each disposed about a centre of inversion with the unlabelled atoms in (a) related by the symmetry operation: 1 − x, 1 − y, −z and those in (b) related by 1 − x, 1 − y, 1 − z. |