Database of Zeolite Structures
 

Framework Type MEI
Type Material
  Material Name: ZSM-18    
 
Chemical Formula:
 
|Na+n (H2O)28| [AlnSi34-n O68]-MEI , n = 2.1 - 5.7
 
   
Unit Cell:
 
hexagonal

 P 63/m (# 176)
    a = 13.1750Å b = 13.1750Å c = 15.8480Å  
    α = 90.000 ° β = 90.000° γ = 120.000°  
   
Framework density:
 
14.3 T/1000 Å3
 
 
Channels:
 
[001] 12 6.9 x 6.9* <-> [001] 7 3.2 x 3.5**
Dimensionality
  Sorption (molecular cross section > 3.4Å): 1-dimensional
  Topological (pore opening > 6-ring): 3-dimensional
   
References:
    Lawton, S.L. and Rohrbaugh, W.J.
   "The framework topology of ZSM-18, a novel zeolite containing rings of three (Si,Al)-O species"
   Science, 247, 1319-1321 (1990)
 
 
Name and Code derivation:
    Zeolite Socony Mobil - eighteen
  ZSM-18 (eighteen)
  MEI
Limiting Rings
 
12-ring viewed along [001]

7-ring viewed normal to [001]