Cancrinite cages

In summary, zeolite L was found to grow via cancrinite cage incorporation, although different mechanisms of incorporation were observed depending on the face of the crystal. When the crystal habit was modified, the features observed on the hexagonal face varied considerably, suggesting growth had been modified. It is possible that this was caused by the occurrence of defects in the crystal. 

The hopping process in the cancrinite cage is only of local nature, and long-range conductivity has been observed only for the sodium cations in the onedimensional 12-ring channels, where the chromate ions are also located [283]. 

Similar effects were noticed in calcined Ca-exchanged erionite where Ca forced K out of the cancrinite cages and modified the cage structure (T9). There is also evidence of reduced water absorption in calcined Re-exchanged faujasite. 

Earlier discussion introduced the concept of using the characteristic truncated octahedral elements of the sodalite framework to explain the molecular architecture of the synthetic zeolites X and Y (see Section. 2.4.3). There are other structural correlations that can be drawn between felspathoids and zeolites, for example, that the cancrinite cage (11-hedron) is a face-sharing element seen in the LTL, ERI, OFF, and EOS frameworks. Furthermore, in nature, salt ion pairs are contained in felspathoid minerals and when these are removed the residual framework exhibits the zeolitic properties of ion exchange and reversible water loss. Other similarities arise in that zeolites can imbibe salt ion pairs, and isotypic structures... 

In the Li,Cs-C all cesium ions are located in the cancrinite cages. They have 12 framework oxygen atoms as neighbours at... 

Cation Exchange. Barrer and Villiger proposed five cation sites in zeolite L these are indicated in Figure 3. Site A is located in the middle of the hexagonal prisms, site B in the centre of the cancrinite cages, site C midway between centres... 

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