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Title: Uncovering the Atomistic Mechanism for Calcite Step Growth

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 in this paper 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. Finally, 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.
Authors:
ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [1]
  1. Curtin Univ., Perth, WA (Australia). Curtin Inst. for Computation/The Inst. for Geoscience Research (TIGeR). Dept. of Chemistry
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division
Publication Date:
Grant/Contract Number:
AC05-00OR22725; FT130100463; DP160100677; ERKCC72
Type:
Accepted Manuscript
Journal Name:
Angewandte Chemie
Additional Journal Information:
Journal Volume: 129; Journal Issue: 29; Journal ID: ISSN 0044-8249
Publisher:
German Chemical Society
Research Org:
Curtin Univ., Perth, WA (Australia); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); Australian Research Council (Australia); Government of Australia; Government of Western Australia
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1376446
Alternate Identifier(s):
OSTI ID: 1401078