Isotactic poly(p-fluorostyrene): X-ray structure determination

Using as a starting point the atomic positions determined by potential energy calculations, the crystal structure of isotactic poly(p-fluorostyrene) has been determined from X-ray diffraction data. It is found that two chains having 4, helical conformations pack into a metrically orthorhombic unit cell with a = 17.6 Å, b = 12.1 Å, and c = 8.25 Å (chain axis). Satisfactory agreement between the calculated and observed structure factors was obtained only when statistical variation of left- and right-handed parallel helices was considered.