Ion clumping makes protons jump more easily in calcium carbonate solutions.

Calcium carbonate helps living organisms build shells and can trap carbon underground. It forms in water at near-neutral pH through rapid chemical reactions, where protons, tiny positively charged particles, constantly hop between molecules. Computer models usually miss this step because they freeze the molecules in one form or only look at tiny groups. To solve this, researchers built a machine-learning model that tracks these chemical reactions over larger sizes and longer times. They simulated how calcium and carbonate ions link up. They found that when ions pair up or form triplets, protons transfer more easily between carbonate, bicarbonate, and carbonic acid. When many ions clump together, proton transfers happen on their own. Clumping and chemical reactions drive each other during the earliest steps of crystal formation.

Why it matters

This matters for understanding how biological structures like shells form and for developing methods to capture carbon dioxide by turning it into minerals. Simulating these processes accurately could lead to better designs for carbon capture systems.

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