Some new habit features in crystals of long chain compounds. Part I. Paraffins

Habits of paraffin crystals were examined with the optical and electron microscope. In particular striations along different crystallographic directions were noticed which could be produced systematically by heat treatment. It was found that such striations often corresponded to geometrically regular ridges. It ie proposed that these ridges represent different phases within the crystals corresponding to structures of differing obliquities all based on the same subcell. Accordingly a variety of structures can be realized within the same crystal by different amounts of simple shear on different planes along the c direction where the shear, while regular, need not be uniform. A number of other less regular morphological features are also described.