1. The 'template' effect of the extra-framework content on zeolite compression: The case of yugawaralite
- Author
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Simona Quartieri, Rossella Arletti, Aldo Gamba, Ettore Fois, Giovanna Vezzalini, and Gloria Tabacchi
- Subjects
pressure induced structural modifications ,high-pressure ,zeolite yugawaralite ,High pressure behavior ,molecular dynamics ,water ,Zeolite ,yugawaralite ,alta pressione ,esperimenti XRPDin situ ,Dinamica molecolare ,zeolites ,dft calculations ,Polyhedron ,first principles MOLECULAR-DYNAMICS ,Geochemistry and Petrology ,framework ,Atom ,Volume contraction ,density functional theory ,Hydrogen bond ,Chemistry ,Crystallography ,Geophysics ,Template ,Chemical physics ,Tetrahedron ,Density functional theory - Abstract
The microscopic behavior of the Ca-zeolite yugawaralite has been studied by ab initio molecular dynamics simulations adopting experimental cell parameters obtained at pressures up to ~9 GPa. Pressure-induced volume contraction occurs via rotations of quasi-rigid TO 4 tetrahedra that reduce the size of the channels in which the extra-framework species are located. Such rotations are governed by deformation of the coordination polyhedron of Ca, which is made up of water and framework O atoms. Contraction of the Ca-H 2 O distances is favored at moderate pressure; at higher pressure the shortening of Ca-framework O atom distances becomes prevalent. The hydrogen bond network plays a fundamental role in the overall response to pressure. Our results indicate that the high- P -induced deformation of the framework structure is strictly correlated to the extra-framework species that act as “templates” in the compression process.
- Published
- 2005