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Penkvilksite-2O: Na2TiSi4O11.2H2O
Marcella Cadoni1, Giovanni Ferraris
1Dipartimento di Scienze Mineralogiche e Petrologiche, Università di Torino, Via Valperga Caluso 35, 10125 Torino, Italy.
Acta Crystallographica. Section C, Crystal Structure Communications
|November 8, 2008
Summary
The crystal structure of synthetic penkvilksite-2O, a microporous titanosilicate, confirms a prior model but reveals disordered water molecule hydrogen bonding. This finding impacts understanding of its unique heteropolyhedral framework and channel structure.
Area of Science:
- Mineralogy
- Crystallography
- Materials Science
Background:
- Penkvilksite-1M structure was previously modeled using order-disorder (OD) theory.
- Microporous titanosilicates exhibit unique structural and functional properties.
Purpose of the Study:
- To determine the crystal structure of synthetic penkvilksite-2O, Na(2)TiSi(4)O(11).2H(2)O.
- To investigate the hydrogen bonding of water molecules within the structure.
- To refine the understanding of its heteropolyhedral framework.
Main Methods:
- Single-crystal X-ray diffraction was used to solve the crystal structure.
- Raman spectroscopy was employed to analyze the hydrogen bonding of water molecules.
Main Results:
- The crystal structure of penkvilksite-2O was confirmed, aligning with major features of a previous OD model.
- A key difference was identified in the hydrogen bonding of water molecules, proposed to be disordered.
- The structure features (100) silicate layers linked by TiO(6) octahedra, forming a corrugated framework with two channels of ~3 Å width.
Conclusions:
- The refined crystal structure of penkvilksite-2O provides detailed insights into its atomic arrangement.
- Disordered hydrogen bonding of water molecules is a significant feature, influencing the overall structure.
- The microporous framework with specific channel dimensions has implications for potential applications in materials science.
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