Figure 1 The asymmetric unit of the title compound. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry codes: (i) 3/2-x, 1/2+y, 1/2-z; (ii) 1/2+x, 1/2-y, -1/2+z; (iii) 2-x, 1-y, -z.]  [article HTML]