Figure 1 Part of the structure of the title compound, showing the atom-numbering scheme and with displacement ellipsoids drawn at the 35% probability level. H atoms have been omitted for clarity. [symmetry codes: (A) -x, y, -z + [{3\over 2}]; (B) -x + 1, y, -z + [{3\over 2}]; (C) x - [{1\over 2}], y + [{1\over 2}], z; (D) -x + [{1\over 2}], y + [{1\over 2}], -z + [{3\over 2}]; (E) x + [{1\over 2}], y + [{1\over 2}], -z]  [article HTML]