Abstract
X-ray diffraction crystal-structure analysis of synthetic fluor-polylithionite, KAlLi2Si4O10F2, shows that this mica has a partially ordered octahedral cation distribution, with one site occupied by Li, and the other by Al1/2Li1/2, approximately. This ordering and distorted tetrahedra cause the surface oxygen ring to be nearly hexagonal, thus allowing polymorphs with 60° stacking rotation angles to occur. The apical Si-O distance is shorter than the basal Si-O, distances.
