Unit cell dimensions of isotactic polyvinylcyclopropane

The unit cell dimensions of isotactic polyvinylcyclopropane were determined, based on crystalline, oriented fiber and film samples. Two structures were found: (1) a hexagonal structure with a = 13.6 Å, c = 6.48 Å, 3₁ helix, space group P3₁ and P3₂, ρ(calc) = 0.9805 g/cm³, ρ(obs) = 0.975 g/cm³; (2) a tetragonal structure with a = 15.21 Å, c = 20.85 Å, 10₃ helix, space group I4 , ρ(calc) = 0.926 g/cm³.