Database of Disordered Zeolite Structures
 
Intergrowth Family CHA-AEI
Periodic Building Unit
 
  Periodic Building Unit (PerBU): CHA-AEI layer  
 
  Layer symmetry C m 1 (1)  
 
 
  References

    SÅ‚awinski, W. A., Wragg D. S., Akporiaye D. and Fjellvåg H.
   "Intergrowth structure modelling in silicoaluminophosphate SAPO-18/34 family"
  Microporous Mesoporous Mat., 195, 311-318 (2014)

Connectivity pattern
Examples


 
Symmetry
Operation*
Translation* Comment Image
i
None
  one inversion center shown as an open circle in the example
m
None
  mirrow plane shown as a solid line in the example
 

* relative to the previous layer


Types of disorder
There are two types of disorder described in the reference above:
(1) A random stacking of the CHA-AEI layers.
(2) A sequence of smaller homogenous blocks of the two polymorphs.

Effect on channel system
  The disorder does not block the channel system
Simplest ordered end members
The color of each layer reflects the symmetry/translation operation used to generate it from the previous layer (see table above).

 
  Polymorph CHA
 
Cell Parameters: trigonal R -3 m (# 166)
    a = 13.6750 Å b = 13.6750 Å c = 14.7670 Å  
  α = 90.0000° β = 90.0000° γ = 120.0000°  
Ring sizes (# T-atoms): 8 6 4  
Channel dimensionality: Topological (pore opening > 6-ring): 3-dimensional  
Channel system: [001] 8 3.8 x 3.8*** (variable due to considerable flexibility of framework)  
 
In this space group and setting, the PerBUs are stacked along [101]

Note: This polymorph corresponds to the ordered framework CHA
 
 
  Polymorph AEI
 
Cell Parameters: orthorhombic C m c m (# 63)
    a = 13.6770 Å b = 12.6070 Å c = 18.4970 Å  
  α = 90.0000° β = 90.0000° γ = 90.0000°  
Ring sizes (# T-atoms): 8 6 4  
Channel dimensionality: Topological (pore opening > 6-ring): 3-dimensional  
Channel system: {[100] 8 3.8 x 3.8 <-> [110] 8 3.8 x 3.8 <-> [001] 8 3.8 x 3.8}***  
 
In this space group and setting, the PerBUs are stacked along [001]
Adjacent layers generated by the same connectivity pattern (same basic color) are shown with different shades for clarity.

Note: This polymorph corresponds to the ordered framework AEI
 
Disorder Example
 
  Simple example of a random stacking
 
  Alternating light and dark colors have been used to highlight the individual layers.