Database of Disordered Zeolite Structures
 
Intergrowth Family CHA-GME
Periodic Building Unit
 
  Periodic Building Unit (PerBU): ABC-6 layer of hexagonally arranged (isolated) 6-rings  
 
  Layer symmetry P (6) m m  
 
  2D cell parameters a = 13.05 Å b = 13.05 Å gamma = 120°    
 
  References
    Millward, G. R., Ramdas, S. and Thomas, J. M.
   "On the direct imaging of offretite, cancrinite, chabasite and other related ABC-6 zeolites and their intergfrowths"
   Proc. R. Soc. Lond., A 399, 57-71 (1985)

Connectivity pattern
Examples
The layers are stacked along the [001] direction using the following connectivity patterns

 
Symmetry
Operation*		 Translation* Comment Image
  Overview showing the A, B and C positions of the ABC-6 layer
0
  A layer
1/3a, 2/3b
  B layer
2/3a, 1/3b
  C layer
 

* relative to the first layer


 
Effect on channel system
  The disorder blocks the 1-dimensional 12-ring channel of gmelinite.
Simplest ordered end members
The color of each layer reflects the translation used to generate it from the first layer (see table above).

 
  Polymorph CHA
 
Cell Parameters: trigonal R -3 m:H (# 166)
  a = 13.6750 Å b = 13.6750 Å c = 14.7670 Å  
  α = 90.000° β = 90.000° γ = 120.000°  
  Volume = 2391.6 Å3
Framework Density (FDSi): 15.1
Ring sizes (# T-atoms): 8  6  4    
Channel dimensionality: Topological (pore opening > 6-ring): 3-dimensional  
ABC-6 sequence: AABBCC   sequence of ABC-6 layers
  Maximum diameter of a sphere:  
    that can be included 7.37 Å  
    that can diffuse along a:  3.72 Å b:  3.72 Å c:  3.72 Å  
    addional volume data  
Composite Building Units:
d6r
cha
In this space group and setting, the PerBUs are stacked along [001]
Note: This polymorph corresponds to the ordered framework CHA
 
 
  Polymorph GME
 
Cell Parameters: hexagonal P 63/m m c: (# 194)
  a = 13.6720 Å b = 13.6720 Å c = 9.8500 Å  
  α = 90.000° β = 90.000° γ = 120.000°  
  Volume = 1594.6 Å3
Framework Density (FDSi): 15.1
Ring sizes (# T-atoms): 12  8  6  4    
Channel dimensionality: Topological (pore opening > 6-ring): 3-dimensional  
ABC-6 sequence: AABB   sequence of ABC-6 layers
  Maximum diameter of a sphere:  
    that can be included 7.76 Å  
    that can diffuse along a:  3.41 Å b:  3.41 Å c:  7.11 Å  
    addional volume data  
Composite Building Units:
d6r
gme
In this space group and setting, the PerBUs are stacked along [001]
Note: This polymorph corresponds to the ordered framework GME
 
Disorder Example
 
 
  The 12-ring channel of GME is blocked by the CHA polymorph

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