Synthetic offretite I. Physicochemical characterization

Recrystallization of magadiite into offretite in the presence of tetramethylammonium cations

“…The sample exhibits an N 2 Brunauer-Emmet-Teller (BET) surface area of 351 m 2 g −1 and the single point total pore volume is 0.27 cm 3 g −1 at a relative pressure (p/p 0 ) of 0.975. The results are close to the standard values 34 and demonstrate that the as-synthesized offretite could not be blocked by erionite (ERI).…”

Incorporation of Gallium into Zeolites: Syntheses, Properties and Catalytic Application

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54 Framework structure of offretite (OFF). (Reprinted with permission from ref . Copyright 1970 Academic Press.

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Structure and Dynamics of Zeolites Investigated by Molecular Dynamics

“…As mentioned above (see section II.D) the Car−Parrinello 14,52,53 CP method allows, in principle, MD simulations of crystals to be performed, and indeed some applications to zeolites have been recently published. − However, the number of degrees of freedom considered in this method is several times larger than for the corresponding classical system, as valence electrons are included explicitely, and, even worst, the time step must be on the order of 0.1 fs, making simulation of zeolites computationally prohibitive. This explains why, to our knowledge, the CP method was applied to three different zeolites only, both having relatively small crystallographic cells: offertite, , sodalite, − and chabazite. , Offertite − has a hexagonal unit cell, containing in the siliceous form 54 atoms (18 Si and 36 O), and shows a system of parallel channels made of small cages (cancrinite cages) connected by 6-membered rings. Other cages (gmelinite cages) showing 6- and 8-membered ring windows link the channels each other.…”