Stacking symbols

Figure 9.6. Illustration of the crystallization process (the layered stacks symbolize the nanocrystals) and shrinkage of the mesostructure in thin films upon heat treatment. 

Figure 3.20. A lateral view of different stacking sequences of triangular nets. They correspond to some typical close-packed structures. The first layer sequence shown corresponds to a superimposition according to the scheme ABABAB... (equivalent to BCBCBC... or CACACA... descriptions) characteristic of the hexagonal close-packed, Mg-type, structure. With reference to the usual description of its unit cell, the full stacking symbol indicating the element, the relative position of the superimposed layers and their distance is Mg Mg. The other sequences correspond to the schemes ABC.ABC. (Cu, cubic), ABAC.ABAC. (La, hexagonal), ACACBCBAB. (Sm, hexagonal). For Cu the constant ch of the (equivalent, non-conventional) hexagonal cell is shown which may be obtained by a convenient re-description of the standard cubic cell (see 3.6.1.3). ch = cV 3, body diagonal of the cubic cell.

Figure 3.25. Stacking symbols applicable to larger unit cells. A, B, C three nodes in the unit cell of a triangular net a, b, c six nodes of a hexagonal net in the unit cell a, 3, p nine nodes of a kagome net in the unit cell. The coordinate doublets are indicated.

Layer stacking symbols (K + 3T slabs formed by kagome and triangular nets) of the main types of Laves phases ... 

The atoms are arranged in close-packed layers stacked in the ABC sequence (see the triangular net stacking symbol). 

For the layer stacking symbols, the data are reported in comparison with the Li3Bi and NaTl-type structures Strukturbericht designation L2,. 

Layer stacking symbols of the NaTl type and of the NaTl-related types are here reported ... 

The section sequence scheme of the CaF2 and AgMgAs types are shown in Fig. 7.29. The layer stacking symbols of the two structures are the following ... 

Layer stacking symbols, triangular, kagome (T,K) nets ... 

The section sequence of the cF24-Cu4MgSn type structure is shown in Fig. 7.31. As for the three cubic structures here presented, their layers stacking symbols in terms of triangular and kagome (T,K) nets are ... 

Owing to the particular values of the z parameters, the layer stacking symbol and the environment data are very similar to those of the Caln2 type. 

Domberger-Schiff K, Backhaits KO, Dmovic S (1982) Polytypism of micas OD-interpretation, stacking symbols, symmetry relations. Clays Clay Minerals 30 364-374 Durovic S (1979) Desymmetrization of OD stractures. KristTech 14 1047-1053... 

LOCAL AND GLOBAL SYMMETRY OF MICA POLYTYPES FROM THEIR STACKING SYMBOLS... 

Phases represented by a (ch ) stacking symbol show only one unique stacking sequence (chh...h). The resulting materials (Table 3.5) are all composed of short columns of (g+1) face-sharing octahedra separated by one layer of apex-shared octahedra, which contributes the isolated c motif. 

Generalized stacking symbols (adapted from Uma-de-Faria Figueiredo,... 

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