 | Acta Crystallographica Section B Acta Crystallographica Section B STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS |
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![[Figure 6]](wf5112fig6mag.jpg)
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Figure 6
(a) Orientation of possible displacement vectors in 1:1 layer silicates with respect to the hexagonal and orthohexagonal unit cells. (Vectors 〈+〉, 〈−〉, 〈*〉 are used in subfamilies C, D). (b) Pictorial representation of the 1M polytype with the aid of symbolic figures – here equilateral triangles. Each triangle represents a structure motif around the local triad of the packet. Important note: the orientation of triangles–symbolic figures (here in the e position) is opposite to those of the triangular faces of octahedra. Hexagonal, orthohexagonal and monoclinic unit-cell vectors are indicated, as well as the displacement vector 〈0〉, and symmetry elements of the polytype (m and a planes). Two superimposed packets are displayed, numbered 0, 1, according to their sequence; the symbolic figures (triangles) are coloured dark yellow and pale blue, respectively. (c) Parts of two adjacent packets in the same orientation with respect to all the vectors indicated. One ring of tetrahedra and three adjacent octahedra around the local triads are displayed for each packet. The position of the local triad of the packet closer to the observer is indicated by the black triangle, in the same orientation as the symbolic figures. |
![[Figure 6]](wf5112fig6.jpg)
| STRUCTURAL SCIENCE CRYSTAL ENGINEERING MATERIALS |
ISSN: 2052-5206
