Class: Zeolite, Tectosilicate
Notable Properties: Gas sorption and separations
Linde Type A gains a place in the history of materials science as being the first synthetic zeolite to be used commercially. Invented in 1953 by Union Carbide (Linde Air Products was a division of Union Carbide) LTA was originally used as a molecular sieve for the removal of dioxygen impurities from gas streams. The material is still in use industrially today. In the laboratory 5Å, 4Å, and 3Å sieves are used for the removal of organic solvents.
The compound can be described as the linkage of sodalite cages by double four ring (d4r) cages. The parent material has a nominal Si:Al ratio of 1:1 with charge balancing sodium cations and 27 zeolitic water molecules filling the pore space prior to desolvation. The material can be made with a variety of other cations as well including potassium lithium magnesium and calcium. The identity of the metal cations in the material is was dictates the nominal pore size (5Å, 4Å, and 3Å).
Na12[(AlO2)12(SiO2)12] • 27 H2O
Unit Cell Parameters:
3D pore structure through with 4.21 Å molecules can diffuse and a large cage 11.05 Å in diameter.