Twin point groups and the polychromatic symmetry of twins

Abstract

Abstract A new classification in terms of the number of independent twin elements is introduced and exploited to analyze the symmetry of multiple twins. The dichromatic point group description of twins is revised showing that, contrary to what stated in the previous literature, all the 58 dichromatic point groups represent the possible symmetry of some twins. This approach is extended in terms of polychromatic point groups and applied to some examples from the recent literature.