Uncovering the Atomistic Mechanism for Calcite Step Growth

Journal Article · Thu Apr 13 00:00:00 EDT 2017 · Angewandte Chemie (International Edition)

DOI:https://doi.org/10.1002/anie.201701701· OSTI ID:1400833

De La Pierre, Marco  ^[1]; Raiteri, Paolo  ^[1]; Stack, Andrew G.  ^[2]; Gale, Julian D.  ^[1]

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1. Department of Chemistry Curtin Institute for Computation/The Institute for Geoscience Research (TIGeR) Curtin University PO Box U1987 Perth WA 6845 Australia
2. Chemical Sciences Division Oak Ridge National Laboratory PO Box 2008, MS-6110 Oak Ridge TN 37831 USA

Abstract Determining a complete atomic‐level picture of how minerals grow from aqueous solution remains a challenge as macroscopic rates can be a convolution of many reactions. For the case of calcite (CaCO ₃ ) in water, computer simulations have been used to map the complex thermodynamic landscape leading to growth of the two distinct steps, acute and obtuse, on the basal surface. The carbonate ion is found to preferentially adsorb at the upper edge of acute steps while Ca ²⁺ only adsorbs after CO ₃ ²⁻ . In contrast to the conventional picture, ion pairs prefer to bind at the upper edge of the step with only one ion, at most, coordinated to the step and lower terrace. Migration of the first carbonate ion to a growth site is found to be rate‐limiting for kink nucleation, with this process having a lower activation energy on the obtuse step.

• Sponsoring Organization: USDOE
• Grant/Contract Number: ERKCC72
• OSTI ID: 1400833
• Journal Information: Angewandte Chemie (International Edition), Journal Name: Angewandte Chemie (International Edition) Vol. 56 Journal Issue: 29; ISSN 1433-7851
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: Germany
• Language: English