Sodalite truncated octahedron unit

Fig. 4. Line representations of zeolite structure (a) sodalite cage, or truncated octahedron (b) type A zeolite unit cell (c) unit cell of types X and Y, or faujasite (d) cation sites in type A (there are 8 1,3 II, and 12 III sites per unit cell) (e) cation sites in types X and Y (161,32 Y, 32 II, 32 IT, 48 III, and 32 IIT, sites per unit cell).

The sodalite unit (or /J cage), which is a characteristic feature of the A, X and Y zeolites (see Figure 11.13), is made up of both four and six rings arranged in the form of a cubo-octahedron (i.e. a truncated octahedron). The cage has an internal effective diameter of about 0.6 nm. 

Fio. 1. Truncated octahedron or sodalite unit vertices represent Si or A1 atoms lines represent oxygens. 

Larger Symmetrical Polyhedral Truncated octahedron (T.O.) or sodalite unit ll-Hedronc or Cancrinite (Cancr.) unit 14-Hedron IIC or gmelinite (gmel.) unit Zeolite Structure... 

The structural unit in Type A zeolite (Linde Type A or LTA), as well as in Types X and Y (faujasite or FAU), is the truncated octahedron shown in Figure 7.1(a). This unit is also called sodalite cage or beta cage, as sodalite is formed by directly... 

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