Invited
Crystallography and symmetry in ferroelectrics

In the field of modern crystallography, since the 19th century, our understanding of crystallographic symmetry has been thoroughly developed. It is symmetry that underlies just about all of our knowledge of the solid state, including ferroelectrics. Yet, despite it importance, the literature is full of incorrect usages which would never be allowed in any other scientific disciplines. Now this is more than a matter of pedantry, but is a serious matter than can result in the unwitting scientist wasting a great deal of time. In this tutorial, I shall discuss some of the aspects of crystallographic symmetry that are often misused and how to correct for them.