The crystal structure of NaY + ND3 has been determined at 20 K by Rietveld analysis of powder neutron diffraction data in space group Fd-3m. The cations were located at site I' (8), site II (32) and at a third site (21) in the α-cage around (0.71, -0.83, 0.25). This reveals a significant migration of the cations from the site I, which is totally emptied, and the site I' to large cages. The sites I and I' are known to be favorable cation sites in bare NaY. All the ND3 detected are located in the α-cage in electrostatic interaction with the Na+-counter-ions and in hydrogen bonding interaction with the framework oxygen atoms. It is for the first time that this double interaction is experimentally evidenced on cationic zeolite with ammonia These interactions provoke a deformation of the C3v molecular symmetry of the ammonia molecule.
|Pages (de - à)||1757-1762|
|Nombre de pages||6|
|journal||Studies in surface science and catalysis|
|Etat de la publication||Publié - 1 déc. 2004|