Figure 7 A view down c of the polymeric structure of (III) in the unit cell. Non-associative H atoms have been omitted. [Symmetry codes: (i) −x, y − , −z + ; (ii) −x, y + , −z + ; (iii) −x + 1, y − , −z + ; (iv) −x + 1, −y, −z + 1; (v) x − 1, −y + , z − .]