Figure 1 The coordination environment of the Cd1 and Cd2 atoms in (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms have been omitted for clarity. [Symmetry codes: (i) −x, −y + 1, −z + 2; (ii) x, −y + , z − ; (iii) x, −y + , z + .]