Database of Zeolite Structures
 

Framework Type HEU
Type Material
  Material Name: Heulandite    
 
Chemical Formula:
 
|Ca2+4 (H2O)24| [Al8Si28 O72]-HEU
 
   
Unit Cell:
 
monoclinic

 C 1 m 1 (# 8)
    a = 17.7180Å b = 17.8970Å c = 7.4280Å  
    α = 90.000 ° β = 116.420° γ = 90.000°  
   
Framework density:
 
17.1 T/1000 Å3
 
 
Channels:
 
{[001] 10 3.1 x 5.5* + 8 4.1 x 4.1*} <-> [100] 8 2.8x 3.4* (variable due to considerable flexibility of framework)
Dimensionality
  Sorption (molecular cross section > 3.4Å): 1-dimensional
  Topological (pore opening > 6-ring): 2-dimensional
   
References:
    Alberti, A.
   "On the Crystal Structure of the Zeolite Heulandite"
   Tschermaks Min. Petr. Mitt., 18, 129-146 (1972)
Merkle, A.B. and Slaughter, M.
   "The crystal structure of heulandite (Ca,Na2)[Al2Si7O18]·6H2O"
   Am. Mineral., 52, 273-276 (1967)
 
 
Name and Code derivation:
    Heulandite
  HEU
Limiting Rings
 
10-ring viewed along [001]

8-ring, also along [001]

8-ring viewed along [100]