Structural aspects of oligothienyl series from X‐ray powder diffraction data

The structures of the series of oligothienyls (T4‐T5‐T6) have been determined and refined from X‐ray powder diffraction data using the Rietveld full‐profile analysis. Unlike polythiophene, all the molecules in the isomorphous series display no internal symmetry, being only approximately planar within 12°. Packing is always achieved through a common molecular disposition, which is usually defined as a herringbone arrangement, with an angle between mean planes of adjacent molecules which spans from 60° to 70°.