Database of Zeolite Structures
 

Framework Type OFF
Type Material
  Material Name: Offretite    
 
Chemical Formula:
 
|(Ca2+,Mg2+)1.5K+ (H2O)14| [Al4Si14 O36]-OFF
 
   
Unit Cell:
 
hexagonal

 P -6 m 2 (# 187)
    a = 13.2910Å b = 13.2910Å c = 7.5820Å  
    α = 90.000 ° β = 90.000° γ = 120.000°  
   
Framework density:
 
15.5 T/1000 Å3
 
 
Channels:
 
[001] 12 6.7 x 6.8* <-> [001] 8 3.6 x 4.9** (3-dimensional)
   
References:
    Bennett, J.M. and Gard, J.A.
   "Non-identity of the Zeolites Erionite and Offretite "
   Nature , 214, 1005-1006 (1967)
Gard, J.A. and Tait, J.M.
   "The crystal structure of the zeolite offretite, K1.1Ca1.1Mg0.7[Si12.8Al5.2O36]·15.2H2O"
   Acta Crystallogr., B28, 825-834 (1972)
Alberti, A., Cruciani, G., Galli, E. and Vezzalini, G.
   "A reexamination of the crystal structure of the zeolite offretite "
   Zeolites, 17, 457-461 (1996)
Mortier, W.J., Pluth, J.J. and Smith, J.V.
   "The crystal structure of dehydrated natural offretite with stacking faults of erionite type"
   Z. Kristallogr., 143, 319-332 (1976)
 
 
Name and Code derivation:
    Offretite
  OFF
Limiting Rings
 
12-ring viewed along [001]

8-ring viewed normal to [001]