Distinct Short-Range Order Is Inherent to Small Amorphous Calcium Carbonate Clusters (<2 nm)

Journal Article · Fri Sep 09 04:00:00 EDT 2016 · Angewandte Chemie (International Edition)

DOI:https://doi.org/10.1002/anie.201604179· OSTI ID:1330881

Sun, Shengtong ^[1]; Chevrier, Daniel M. ^[2]; Zhang, Peng ^[2]; Gebauer, Denis ^[3]; Cölfen, Helmut ^[3]

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1. Physical Chemistry, University of Konstanz, Universitätsstrasse 10 78457 Konstanz Germany; School of Chemical Engineering, State Key Laboratory of Chemical Engineering, Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, East China University of Science and Technology, 130 Meilong Road Shanghai 200237 P.R. China
2. Department of Chemistry and Institute for Research in Materials, Dalhousie University, Halifax Nova Scotia B3H 4R2 Canada
3. Physical Chemistry, University of Konstanz, Universitätsstrasse 10 78457 Konstanz Germany

Amorphous intermediate phases are vital precursors in the crystallization of many biogenic minerals. While inherent short-range orders have been found in amorphous calcium carbonates (ACCs) relating to different crystalline forms, it has never been clarified experimentally whether such orders already exist in very small clusters less than 2 nm in size. Here, we studied the stability and structure of 10,12-pentacosadiynoic acid (PCDA) protected ACC clusters with a core size of ca. 1.4 nm consisting of only seven CaCO₃ units. Ligand concentration and structure are shown to be key factors in stabilizing the ACC clusters. More importantly, even in such small CaCO₃ entities, a proto-calcite short-range order can be identified but with a relatively high degree of disorder that arises from the very small size of the CaCO₃ core. Our findings support the notion of a structural link between prenucleation clusters, amorphous intermediates, and final crystalline polymorphs, which appears central to the understanding of polymorph selection.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: FOREIGN
• OSTI ID: 1330881
• Journal Information: Angewandte Chemie (International Edition), Journal Name: Angewandte Chemie (International Edition) Journal Issue: 40 Vol. 55; ISSN 1433-7851
• Publisher: Wiley
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY