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Calcium Carbonate Formation in the Presence of Biopolymeric Additives
Published on: May 14, 2019
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Unlocking the mysterious polytypic features within vaterite CaCO3
Xingyuan San1, Junwei Hu2, Mingyi Chen2
1Hebei Key Lab of Optic-electronic Information and Materials, The College of Physics Science and Technology, Hebei University, Baoding, 071002, China.
Nature Communications
|November 29, 2023
Summary
Vaterite, a form of calcium carbonate, is revealed to be a polytypic structure with a monoclinic lattice. This discovery clarifies vaterite
Area of Science:
- Mineralogy
- Crystallography
- Biomineralization
Background:
- Calcium carbonate (CaCO3) is Earth's most abundant biogenic mineral, vital for the hydrosphere, biosphere, and climate.
- Vaterite, one of CaCO3's polymorphs, has a debated structure persisting for a century.
Purpose of the Study:
- To elucidate the atomic-scale structure of vaterite.
- To resolve the long-standing debate on vaterite's crystallographic nature.
Main Methods:
- Transmission electron microscopy (TEM) for direct imaging.
- Crystallographic analysis for structural determination.
- Machine learning-aided molecular dynamics simulations with ab initio accuracy.
Main Results:
- Vaterite is identified as a polytypic structure with a basic monoclinic lattice and pseudohexagonal symmetry.
- Single vaterite grains contain up to three orientation variants.
- Vaterite exhibits a second-order phase transition around 190 K.
Conclusions:
- The study provides a comprehensive atomic-scale understanding of vaterite structure.
- Findings offer new perspectives on calcium carbonate biomineralization processes.
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