Chemistry of soil minerals. Part VI. Salt entrainment by sodalite and cancrinite during their synthesis

Abstract

The imbibition of salts by sodalite and cancrinite during their hydrothermal formation from kaolinite has been studied. Isotherm contours recalling those of Langmuir's isotherm were observed in sodalite for NaCI, NaBr, NaCIO,, NaCIO,, and Na,CO,.These results have been interpreted in terms of a Donnan equilibrium, in which solid-phase activities were calculated on the experimentally justified assumption that each sodalite cage is capable of accommodating a particular number of each kind of guest molecule, which number varies with the size of the guest. The stoicheiometry, thermal stability, chemical reactivity, and crystallization kinetics of representative compounds have been discussed, and the possible importance of salt inclusion in other zeolitic materials has been noted.

Caracterização e análise estrutural da hidroxisodalita sintetizada a partir de amostras de solo amazônico

“…A e B são espécies capazes de formar tetraedros (Al e Si) e X pode ser uma variedade de ânions mono e divalentes. A estrutura está baseada em uma cadeia octaédrica truncada formada pela união de átomos de Si e Al ligado tridimensionalmente [8,9].…”

3-D Periodic Packaging: Sodalite, a Model System

“…The area of the pore opening increases 80% so that the structure becomes much more permeable. The T-O-T' angle increases 200 in going from Na 3 0(AlSiO4)304H 2 0 to NasO(AISiO4) 3 and the sodium atom moves to within 0.24 A of the center of the pore opening. 0.24 A is the displacement required for the Na3 3 * cluster identity to be lost and the structure to be transformed into an expanded Na+ lattice.…”

“…This has been supported by our recent studies of the nonlinear optical response of the four noncentrosymmetric sodalites with the above compositions (25). Second harmonic generation (SHG) measurements performed on the crystalline powders using Nd-Yag 1064 nm radiation showed that substitution of silicon by germanium in Na 3 [](AlSiO 4 )3o4H 2 0 and Na 3 [](GaSiO 4 ) 3 *4H 2 0 increases SHG efficiency by factor of 3 while substitution of aluminum by gallium in Na 3 0(A1SiO 4 ) 3 *4H 2 0 and Na 3 0(A1GeO4) 3 *4H 2 0 increases SHG by only 30%. Evaluation of the P43m point group X(123) nonzero polarizabiity tensor elements using the SHG measurements for this series is in progress.…”

“…This is denoted in empirical formulae by 0, e.g Na 3 0(AlSi04) 3 for an "empty" cage containing [ Figure 3. Removal of the Br-atom from the center of the cage and one sodium atom from the [Na4]3 + tetrahedron along with some displacement of the sodium atoms gives the topography of the (Na 3 ]3 + cluster.…”

“…A series of samples was prepared with different concentrations of [Na 4 ] 3 clusters formed by diffusion of sodium atoms into the "empty" Na 3 J(AdSiO4) 3 sodalite cages. The diffuse reflectance spectra of the samples containing approximately one (Na 4 ]3+ cluster per 50, 10 and 4 empty cages are shown in Figure 4.…”