Crystal structures of clay minerals and their X-ray identification / Кристаллические структуры глинистых минералов и их рентгеновская идентификация

The terms interlayering, mixed-layering, and interstratification describe phyllosilicate structures in which two or more kinds of layers occur in a vertical stacking sequence, that is, along c* or a line normal to (001). Phyllosilicate layers are strongly bonded internally but rather weakly bonded to each other. Thus, each layer approximates a one-dimensional “molecule” in the e* direction, and a two-dimensional crystal in the a and b directions. The basal surfaces of different kinds of layers are geometrically very similar and consist of sheets of oxygen or hydroxyl ions in quasi-hexagonal array. Consequently, layers with different internal arrangements can stack together and still articulate well at their interfaces. These structural factors are almost unique to the clays and phyllosilicates generally, and doubtless are responsible for the common occurrence of interstratified species. <...>