Crystalline Zeolites. II. Crystal Structure of Synthetic Zeolite, Type A

Abstract

The new synthetic zeolite. Type A, is cubic, a" -12.32 A., and X-ray data are consistent with space group 01-Pm.'lni.The unit cell composition is Mei2/" ](A102)i2(Si02)i2]-fVH20 where Me is an exchangeable cation of charge n, and N varies from 20 to 30, The unit cell dimension varies slightly with the cation present. The aluminosilicate framework consists of 24(Si,Al)A), tetrahedra which are joined to form 8-membered oxygen rings in the faces and distorted 6-membeved rings on the 3-fold axes. A large cavity 11.4 A. in diameter occupies the center of the cell and smaller 6.6 A. cavities are located on the 3-fold axes.Probable positions of the cations in the lithium, sodium, thallium and calcium forms are indicated, and correlation of the structure with the adsorptive and ion-exchange properties of the Type A zeolite is discussed.

Molecular Sieve Science and Technology

“…By March 1954 they achieved their final structure for the A zeolite, verifying it shortly thereafter with single crystal x-ray data on a 30 micron A crystal that Breck and Nancy A. Acara had recently grown [17]. By mid 1954, they also completed the structures of X and faujasite [18], with help from single crystal xray data on faujasite.…”

The Chemistry, Crystallization, Physicochemical Properties and Behavior of Sodium Aluminosilicate Solid Phases: Final Report

“…X-ray powder diffraction and transmission electron diffraction analyses showed that different sodium aluminosilicate solids phases formed from supersaturated nitrate/nitrite-rich sodium aluminate solutions with time during the course of crystallization and followed the sequence: Crystalline phase identification, subsequent to complete transformation of the X-ray indifferent amorphous phase, was performed using established, standard diffraction lines for zeolite, sodalite and cancrinite [1][2][3][4][5][6][7][8] Table 2. Cancrinite (Na 8 Al 6 Si 6 O 24 (NO 3 ) 2 .4H 2 O) Occasionally, particles of about 50 mm wide and 500 nm long were present.…”

Template-based syntheses for shape controlled nanostructures

“…A high Si/Al ratio gives to the zeolites a high thermal stability [6,7]. The first zeolite was prepared in 1950s under hydrothermal conditions in basic aqueous media and using inorganic cations as charge-balancing species [8][9][10]. Since then, many approaches have been made which have enabled the discovery a large number of new zeolite framework types.…”