The atomic structure and dynamics at the CaCO₃ vaterite-water interface: A classical molecular dynamics study.

Area of Science:

• Mineralogy and Surface Chemistry
• Computational Materials Science
• Biomineralization Studies

Background:

• Vaterite, a rare calcium carbonate polymorph, has poorly understood surface properties and stability.
• Its role in biomineralization processes requires detailed investigation of its interactions with aqueous environments.

Purpose of the Study:

• To explore the structure and dynamics of water on vaterite surfaces using molecular and lattice dynamics.
• To identify stable vaterite surfaces and understand their behavior in aqueous solutions.
• To provide theoretical insights into vaterite's surface chemistry and its implications for biomineralization.

Main Methods:

• Classical molecular and lattice dynamics simulations.
• Generation and pre-screening of vaterite surfaces based on surface energies.
• Simulations in both implicit and explicit water environments.
• Analysis of water density profiles and residence times at calcium sites.

Main Results:

• Most vaterite surfaces exhibit low stability and dissolve rapidly in water.
• Three stable vaterite surfaces were identified with minimal structural changes upon water contact.
• These stable surfaces display two distinct hydration layers.
• Water residence times at calcium sites suggest potential for binding with organic molecules.

Conclusions:

• Vaterite's low stability in abiotic environments is highlighted, with specific surfaces showing resilience.
• The identified stable surfaces provide realistic models for studying vaterite's surface chemistry.
• Understanding water-surface interactions is crucial for predicting the adsorption of molecules and vaterite's role in biomineralization.