Database of Disordered Zeolite Structures
 
Intergrowth Family ERI-OFF
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
    Bennett, J.M. and Gard, J.A.
   "Non-identity of the Zeolites Erionite and Offretite"
   Nature, 214, 1005-1006 (1967)

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 offretite.
Simplest ordered end members
The color of each layer reflects the translation used to generate it from the first layer (see table above).

 
  Polymorph ERI
 
Cell Parameters: hexagonal P 63/m m c: (# 194)
  a = 13.0540 Å b = 13.0540 Å c = 15.1750 Å  
  α = 90.000° β = 90.000° γ = 120.000°  
  Volume = 2239.5 Å3
Framework Density (FDSi): 16.1
Ring sizes (# T-atoms): 8  6  4    
Channel dimensionality: Topological (pore opening > 6-ring): 3-dimensional  
ABC-6 sequence: AABAAC   sequence of ABC-6 layers
  Maximum diameter of a sphere:  
    that can be included 7.04 Å  
    that can diffuse along a:  3.42 Å b:  3.42 Å c:  3.42 Å  
    addional volume data  
Composite Building Units:
d6r
can
In this space group and setting, the PerBUs are stacked along [001]
Note: This polymorph corresponds to the ordered framework ERI
 
 
  Polymorph OFF
 
Cell Parameters: hexagonal P -6 m 2: (# 187)
  a = 13.0630 Å b = 13.0630 Å c = 7.5650 Å  
  α = 90.000° β = 90.000° γ = 120.000°  
  Volume = 1118.0 Å3
Framework Density (FDSi): 16.1
Ring sizes (# T-atoms): 12  8  6  4    
Channel dimensionality: Topological (pore opening > 6-ring): 3-dimensional  
ABC-6 sequence: AAB   sequence of ABC-6 layers
  Maximum diameter of a sphere:  
    that can be included 7 Å  
    that can diffuse along a:  3.43 Å b:  3.43 Å c:  6.61 Å  
    addional volume data  
Composite Building Units:
d6r
can
gme
In this space group and setting, the PerBUs are stacked along [001]
Note: This polymorph corresponds to the ordered framework OFF
 

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