The crystal structure of polytetrahydrofuran

The results of a detailed investigation on the crystal structure of poly‐tetrahydrofuran are reported. The unit‐cell has a monoclinic symmetry, with a = 5.61 ± 0.04 Å, b = 8.92 ± 0.05 Å, c = 12.25 ± 0.10 Å (fiber axis), and β = 134°30′; space‐group C 2/ c . It was concluded for a planar zig‐zag, but not full linear, chain conformation. Two models arising from an enlargement of different bond angles are proposed and discussed. No definitive choice has been drawn, owing to the same agreement factor between observed and calculated data obtained for both models.