Database of Zeolite Structures
 

Framework Type MEI
Reference Material
  Material Name: ZSM-18    
 
Chemical Formula:
 
|Nax (H2O)28 | [AlxSi34-xO68]-MEI  (x=2.1-5.7)
 
   
Unit Cell:
 
hexagonal

 P 63/m (# 176)
    a' = 13.1750 Å b' = 13.1750 Å c' = 15.8480 Å  
    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)
DOI: 10.1126/science.247.4948.1319
 
 
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]