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Network Connectivity, Bond Lengths, and Modifier Coordination in Alkali Aluminoborosilicate Glasses
Anders K R Christensen1, Oliver L G Alderman2, Randall E Youngman3
1Department of Chemistry and Bioscience, Aalborg University, Aalborg DK-9220, Denmark.
Inorganic Chemistry
|February 18, 2026
Summary
Alkali modifiers like lithium, sodium, and potassium significantly impact aluminoborosilicate glass structure. Neutron diffraction and NMR reveal how these elements influence bonding and coordination, aiding in material design.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Glass Science
Background:
- Aluminoborosilicate glasses are crucial in various industries.
- The precise structural role of alkali modifiers (Li, Na, K) is not fully understood.
- Understanding these roles is key to optimizing glass properties.
Purpose of the Study:
- To elucidate the structural contributions of Li, Na, and K in aluminoborosilicate glasses.
- To investigate the influence of alkali-field strength and B/Al ratio on glass structure.
- To establish clearer composition-structure-property relationships for these materials.
Main Methods:
- Synthesis of aluminoborosilicate glasses with varying alkali and boron/aluminum content.
- Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy to determine coordination states.
- Isotopic-difference neutron total scattering and improper difference methods for structural analysis.
Main Results:
- Tetrahedral coordination of aluminum (Al) is consistent across different alkali modifiers (~98%).
- Fraction of tetrahedral boron (B) increases with lower alkali-field strength and higher B/Al ratio.
- Li-O and Na-O bonds show asymmetric distributions and increasing coordination with higher B/Al ratios.
Conclusions:
- Alkali modifiers play a nuanced structural role, influencing B coordination and bond characteristics.
- The findings provide critical insights into the structure of alkali-modified aluminoborosilicate glasses.
- This research advances the understanding needed for targeted design of advanced glass materials.
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