Structure and Liquid Fragility in Sodium Carbonate

Area of Science:

• Computational chemistry and materials science.
• Investigating the properties of molten salts.

Background:

• Understanding the structure-dynamics relationship in molten salts is crucial for their applications.
• Molten sodium carbonate exhibits complex behavior influenced by its local structure.

Purpose of the Study:

• To explore the relationship between local structure and dynamics in molten sodium carbonate.
• To develop a model that captures the flexibility and charge distribution of the carbonate anion.
• To identify key interactions governing the formation of temperature-dependent structures.

Main Methods:

• Development of a flexible fluctuating-charge model for the carbonate molecular anion.
• Simulations to observe the evolution of low-dimensional structures.
• Analysis of how varying anion charge distribution affects structural connectivity and dynamics.

Main Results:

• Identified highly temperature-dependent complex low-dimensional structures controlling liquid fragility.
• Demonstrated that changes in molecular anion charge distribution directly influence these structures.
• Showed that increased charge separation within carbonate ions enhances structural connectivity and liquid fragility.

Conclusions:

• The local structure of molten sodium carbonate, particularly its low-dimensional arrangements, dictates its dynamics and fragility.
• The developed fluctuating-charge model effectively rationalizes the role of anion charge distribution in structure formation.
• Tailoring the charge distribution of carbonate ions offers a pathway to control the properties of molten sodium carbonate.