Modelling regularity of Si/Al distributions in disordered tectosilicates - application to zeolites with the GIS...

Area of Science:

• Mineralogy
• Materials Science
• Crystallography

Background:

• Tectosilicates, including zeolites, exhibit complex silicon-aluminum ordering.
• Understanding this ordering is crucial for their properties and applications.
• Previous work established a foundation for analyzing these structures.

Purpose of the Study:

• To extend previous work by analyzing Si/Al distributions in tectosilicates.
• To develop and apply a novel method for characterizing order/disorder.
• To identify and describe submicroscopic ordered and disordered substructures.

Main Methods:

• Analysis of inter-relations between maximal independent sets.
• Utilizing a labelled quotient graph of the net.
• Application to various natural and synthetic tectosilicates, including GIS framework zeolites.

Main Results:

• Identification of specific disordered substructures, termed 'alveoli'.
• Demonstration of partial order in submicroscopic domains coexisting with ordered regions.
• Successful application to bikitaite, chabazite, analcime, gismondine, amicite, garronite, gobbinsite, and synthetic Na-P2.

Conclusions:

• The maximal independence principle applied to the labelled quotient graph effectively explains composition and order/disorder.
• The findings align well with existing 29Si magic-angle spinning NMR data.
• The method provides a robust framework for analyzing Si/Al distribution in tectosilicates.