Beauty and Complexity of Calcium Carbonate Precipitation: Optical Microscopy and in situ Raman Microspectroscopy Characterization

Article Article scientifique Article Beauty and Complexity of Calcium Carbonate Precipitation: Optical Microscopy and in situ Raman Microspectroscopy Characterization eng 2025-01-02 author Barbosa Natercia 0000-0001-9800-3514 Department of Physical Chemistry, Sciences II, University of Geneva, Geneva 1211, Switzerland 839283 Chimie physique (groupe 8) (CHIF8) author Khakhula Tetiana 0009-0001-2551-3254 Department of Physical Chemistry, Sciences II, University of Geneva, Geneva 1211, Switzerland 409987 author Brazard Johanna 0000-0002-2246-4856 Department of Physical Chemistry, Sciences II, University of Geneva, Geneva 1211, Switzerland 930550 Département de chimie physique (CHIFI) author Adachi Takuji 0000-0002-0577-1926 Department of Physical Chemistry, Sciences II, University of Geneva, Geneva 1211, Switzerland 930973 Département de chimie physique (CHIFI) acs.cgd.4c01063 10.1021/acs.cgd.4c01063 1528-7483 https://pubs.acs.org/doi/10.1021/acs.cgd.4c01063 Calcium carbonate is one of the most studied systems in several disciplines (chemistry, biology, geology, etc.). Its crystallization process has been highly debated, and contradicting claims can be found in the literature. The controversy may be attributed to various initial conditions (concentration, pH, with or without additives), different precipitation protocols among literature, and the methods adopted with a large gap in the length scale: electron microscopy at the nano- and spectroscopic means at the bulk scale. Here, we investigated calcium carbonate precipitation by combining optical microscopy with in situ Raman microspectroscopy as a mesoscopic length scale technique. The precipitation of calcium carbonate was performed by mixing CaCl2 and Na2CO3 from a wide range of supersaturations without stirring to screen all possible crystallization pathways. We categorized and characterized the initial precipitates observed upon mixing as gel, gel + amorphous calcium carbonate (ACC), ACC, crystal, and no precipitate. Calcite and vaterite were observed in all mixed solutions, while aragonite was observed in most of them. This study shows how complex and heterogeneous yet beautiful CaCO3 precipitation is, and it emphasizes the importance of studying the system at the length scale between nano and bulk as well as that of initial conditions in order for the debates to converge in the near future. Dewey 540 Swiss National Science Foundation Molecular level understanding of crystal nucleation and polymorphism by in-situ optical spectroscopy combined with deep learning-assisted simulations 219291 CH Projects 38 Département de chimie physique 142 false 1393 Groupe Adachi Crystal growth & design 1dbd1ea1-d658-40ef-bc71-c09d54ff399c Article (Accepted version) Public Beauty_and_Complexity_of_Calcium_Ca.pdf 2248441 application/pdf Restricted 2026-01-03 d17931e2b35f6940d4ed4198d4677b22801c7e900ba7d7319de1ff7fab78bdd4 014fc7db-0a24-445c-8b49-5133a0a0f6ef Article (Published version) Restricted barbosa-et-al-2025-beauty-and-compl.pdf 2844232 application/pdf f3ec5960f61db2c3d716b5f7c6dbdbb2c9e5fb85ce4c924ce50c485822a1da73 openAccess Faculté des sciences / Section de chimie et biochimie / Département de chimie physique

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Beauty and Complexity of Calcium Carbonate Precipitation: Optical Microscopy and in situ Raman Microspectroscopy Characterization	Crystal growth & design			2025	202	121

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