Abstract A selection of novel materials exhibiting smectic polymorphism has been studied by X-ray diffraction. The smectic A and smectic C phases were generally identified from the diffraction patterns of mag netically aligned samples in Lindemann tubes. Some of the crystal smectic phases were identified by indexing the diffraction lines from the powder patterns. However it was not possible to distinguish between the hexatic phases (i.e., SB, SF and SI) by diffraction from magnetically aligned samples in Lindemann tubes because sufficiently large monodomains could not be obtained. We therefore prepared monodomain, free-standing films and recorded diffraction patterns. The distribution of scattered X- ray intensity amongst the six equatorial spots is characteristic of the phase if the beam is perpendicular to the smectic layers. However, if the beam is not perpendicular, identifying the phase is more complicated. We have therefore calculated the diffraction pattern expected for any unit cell and angle of i...