Combined Neutron and X-ray Powder Diffraction Study of Zeolite Ca LSX and a 2H NMR Study of Its Complex with Benzene

Gas adsorption microcalorimetry and modelling to characterise zeolites and related materials

“…The distributions of the extra-framework cations for LiX [58] and KX [59] provided by recent reinvestigation of these crystal structures include the occupation of sites I′, II, III and III′ for Li + and sites I, I′, II, III and III′ for K + . For the divalent cations, we started from a diffraction refinement of the dehydrated CaX faujasite [60] where the 48 Ca 2+ extra-framework cations are distributed as follows: 16 Ca 2+ cations in sites I located in the centre of hexagonal prisms which connect the sodalite cages and 32 Ca 2+ in sites II. This distribution of the extraframework cations was also used to model in a first approximation BaX [61], SrX and MnX faujasite systems.…”

Adsorption of thiophene and benzene in sodium-exchanged MFI- and MOR-type zeolites: A molecular simulation study

“…These substitutions create a net negative charge in the frame, which is compensated by a cation. The sites of atoms influence the adsorption and the catalytic properties of the materials [3]. Although crystalline silica structures are well determined, the substitution of aluminum for silicon induces chemical disorder.…”

Studying porous materials with krypton-83 NMR spectroscopy

“…Unlike Na C , the Ca 2C cation preferentially occupies site I, thus distorting the faujasite framework at the double six-ring. 56,57 This leads to greater long-range disorder in the framework (as confirmed by X-ray crystallography), as well as a more pronounced difference in the placement of Ca 2C cations in different supercages. Such long-range disorder could have caused isotropic chemical shift dispersion, and therefore field-dependent linewidth, only if the length scale of the disorder were greater than the displacement experienced by the krypton during its T 2 limited coherence lifetime.…”