Figure 2 The crystal structure of the title compound viewed along the c axis. All H atoms have omitted for clarity. Symmetry codes: (v) -x + 1, y - 1, z; (vi) x - [{1\over 2}], y - [{1\over 2}], z; (viii) x - [{1\over 2}], y + [{1\over 2}], z.  [article HTML]