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).

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  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
 
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  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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