The crystal structure of isotactic trans‐1,4 poly‐1‐ethyl‐butadiene

The crystal structure of isotactic trans ‐1,4 poly‐1‐ethyl butadiene is described; this is the first complete structural study of a “ditactic” polymer. The unit cell has an orthorhombic symmetry with the constants a = 14.02 ± 0.10 Å; b = 8.02 ± 0.05 Å; c = 4.85 ± 0.05 Å (fibre axis); Z = 4. The space group is P2 1 2 1 2 1 ; it requires isomorphous macromolecules in the crystals. The structure was solved by “trial and error” methods; the agreement between observed and calculated structure factors is satisfactory.