Structural and Elastic Behaviour of Sodalite Na8(Al6Si6O24)Cl2 at High-Pressure by First-Principle Simulations

Abstract

Sodalite Na8(Al6Si6O24)Cl2 (space group P4¯3n) is an important mineral belonging to the zeolite group, with several and manyfold fundamental and technological applications. Despite the interest in this mineral from different disciplines, very little is known regarding its high-pressure elastic properties. The present study aims at filling this knowledge gap, reporting the equation of state and the elastic moduli of sodalite calculated in a wide pressure range, from −6 GPa to 22 GPa. The results were obtained from Density Functional Theory simulations carried out with Gaussian-type basis sets and the well-known hybrid functional B3LYP. The DFT-D3 a posteriori correction to include the van der Waals interactions in the physical treatment of the mineral was also applied. The calculated equation of state parameters at 0 GPa and absolute zero (0 K), i.e., K0 = 70.15(7) GPa, K’ = 4.46(2) and V0 = 676.85(3) Å3 are in line with the properties derived from the stiffness tensor, and in agreement with the few experimental data reported in the literature. Sodalite was found mechanically unstable when compressed above 15.6 GPa.

First-Principles Investigation of Electrides Derived from Sodalites

“…This indicates a minor effect of dispersion correction in the sodalites. Our results are close to other DFT results in which the calculated lattice parameters are 8.721, 8.91, and 8.78 Å …”

“…Our results are close to other DFT results in which the calculated lattice parameters are 8.721, 51 8.91, 52 and 8.78 Å. 53 Figure 3 shows the band structures and density of states (DOS) of all four sodalite materials. Clearly, none of their electronic structures show spin polarization in their band structures.…”

Coal fly ash derived zeolite: a solid-state base for convenient synthesis of diphenyl ethers

“…approximately equal percentages for Si and Al and the presence of Na as a counterion in the framework. 36 As discussed above, sodalite was envisaged as a substitute for the conventional base in diphenyl ether synthesis. Therefore, the point of zero charge (pH pzc ) was determined to ensure that there is no basicity in the proposed material due to any residual NaOH used during its synthesis.…”

A facile recrystallization strategy for fabrication of nanocrystalline microspheres of sulfatic sodalite with high thermal stability

“…218) and a chemical formula of Na 8 [SiAlO 4 ] 6 Cl 2 . 1,7,8 In comparison, synthetic sodalite usually has variable amounts of water and hydroxyl in the formulas dependent on the conditions of hydrothermal synthesis or subsequent heat treatments at elevated temperatures: i.e. , the basic sodalite (B-sodalite) series Na 8 [AlSiO 4 ] 6 (OH) 2 · n H 2 O (0 < n ≤ 4) and the hydrosodalite series Na 6 [AlSiO 4 ] 6 · n H 2 O (0 < n ≤ 8).…”

“…218) and a chemical formula of Na 8 [SiAlO 4 ] 6 Cl 2 . 1,7,8 In comparison, synthetic sodalite usually has variable amounts of water and hydroxyl in the formulas dependent on the conditions of hydrothermal synthesis or subsequent heat treatments at elevated temperatures: i.e., the basic sodalite (B-sodalite) series Na 8 [AlSiO 4 ] 6 (OH) 2 •nH 2 O (0 < n ≤ 4) and the hydrosodalite series Na 6 [AlSiO 4 ] 6 •nH 2 O (0 < n ≤ 8). 9 In order to obtain improved properties and applications, [9][10][11] the sodalite family has evolved into diverse chemical, topological, geometrical, and crystallographic variants with a general formula Na 6 [AlSiO 4 ] 6 (NaX)m•(H 2 O)n (where X = Cl, OH, SO 4 , CO 3 , …; m = 0-2; n = 0-8).…”