A review of structural tendencies, as observed in several synchrotron radiation diffraction studies of Aurivillius phases, is presented. The role of powder synchrotron radiation is analyzed. Investigated phases belong to Aurivillius families with n from 3 to 6, with partial substitution of small Ti cations and of large Bi cations. Representative formulas are: Bi 4 Ti 3− x W x O 12 , Bi n +1 Ti 3 Fe n −3 O 3n +3 and (Ba, Pb) 2 Bi 4 Ti 5 O 18 . Observed general behavior shows a tendency to increase disorder with increasing chemical complexity. The structure-polarization relationship in Ba 2 Bi 4 Ti 5 O 18 is investigated and a paradox between published results is highlighted. Synchrotron radiation results tend to confirm Lightfoots's conclusions, suggesting electric polarization along the z axis.