Database of Disordered Zeolite Structures
 
Intergrowth Family Beta
Periodic Building Unit
 
  Periodic Building Unit (PerBU): beta layer  
 
  Layer symmetry P (-4) m 2  
 
 
  References

    Higgins, J.B., LaPierre, R.B., Schlenker, J.L., Rohrman, A.C., Wood, J.D., Kerr, G.T. and Rohrbaugh, W.J.
   "The framework topology of zeolite beta"
  Zeolites, 8, 446-452 (1988)

    Newsam, J.M., Treacy, M.M.J., Koetsier, W.T. and de Gruyter, C.B.
   "Structural characterization of zeolite beta"
  Proc. R. Soc. Lond. A, 420, 375-405 (1988)

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

 
Symmetry
Operation*
Translation* Comment Image
m
1/3 a
  the next layer cannot be translated along a
m
-1/3 a
  the next layer cannot be translated along a
m
1/3 b
  the next layer cannot be translated along b
m
-1/3 b
  the next layer cannot be translated along b
m
none
  connectivity pattern for the next layer changes
with each m operation
 

* relative to the previous layer

Short explanation:
The "purple layer" is a mirror image of the previous layer (symmetry operation m) and is translated 1/3 of a unit cell along a.
Note: The next layer cannot be translated along the same axis, e.g. a "purple" layer can only be followed by a yellow, blue or green layer.

Detailed Explanation:
Each application of a mirror operation changes the pattern of the connecting T atoms. If they form rows along the a direction on the top surface of the previous layer, only translations of zero (green layer) or ±1/3 a (purple or brown layer) are possible. If they form rows along the b direction (gray spheres), only translations of zero (green layer) or ±1/3 b (yellow or blue layer) are possible. The connecting T atoms (those pointing up) from the top surface of the previous layer (gray layers) are highlighted as spheres in the examples to the right.
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 A (Beta_A)
 
Cell Parameters: tetragonal P 41 2 2 (# 91)
    a = 12.6614 Å b = 12.6614 Å c = 26.4061 Å  
  α = 90.0000° β = 90.0000° γ = 90.0000°  
Ring sizes (# T-atoms): 12 6 5 4  
Channel dimensionality: Topological (pore opening > 6-ring): 3-dimensional  
Channel system: <100> 12 6.6 x 6.7** <-> [001] 12 5.6 x 5.6*  
 
Beta_A is chiral and has an enantiomer with the space group 43 2 2
In this space group and setting, the PerBUs are stacked along [001]


Note: This polymorph has NOT been observed as a pure ordered material
 
 
  Polymorph B (Beta_B)
 
Cell Parameters: monoclinic C 1 2/c 1 (# 15)
    a = 17.8965 Å b = 17.9200 Å c = 14.3282 Å  
  α = 90.0000° β = 114.8030° γ = 90.0000°  
Ring sizes (# T-atoms): 12 6 5 4  
Channel dimensionality: Topological (pore opening > 6-ring): 3-dimensional  
 
In this space group and setting, the PerBUs are stacked along [001]


Note: This polymorph has NOT been observed as a pure ordered material
 
 
  Polymorph CH (Beta_CH)
 
Cell Parameters: monoclinic P 1 2/c 1 (# 13)
    a = 12.2815 Å b = 12.2847 Å c = 27.4117 Å  
  α = 90.0000° β = 107.2880° γ = 90.0000°  
Ring sizes (# T-atoms): 12 6 5 4  
Channel dimensionality: Topological (pore opening > 6-ring): 3-dimensional  
 
In this space group and setting, the PerBUs are stacked along [001]
Beta_CH is an ordered intergrowth of Beta_A and Beta_B

Note: This polymorph has NOT been observed as a pure ordered material
 
 
  Polymorph BEC
 
Cell Parameters: tetragonal P 42/m m c (# 131)
    a = 12.7700 Å b = 12.7700 Å c = 12.9770 Å  
  α = 90.0000° β = 90.0000° γ = 90.0000°  
Ring sizes (# T-atoms): 12 6 5 4  
Channel dimensionality: Topological (pore opening > 6-ring): 3-dimensional  
Channel system: [001] 12 6.3 x 7.5* <-> <100> 12 6.0 x 6.9**  
 
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 BEC
 
Disorder Example
 
  Simple example of a random stacking
 
  There is no blocking of the 3D channel system.