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Title: Disordered amorphous calcium carbonate from direct precipitation

Amorphous calcium carbonate (ACC) is known to play a prominent role in biomineralization. Different studies on the structure of biogenic ACCs have illustrated that they can have distinct short-range orders. However, the origin of so-called proto-structures in synthetic and additive-free ACCs is not well understood. In the current work, ACC has been synthesised in iso-propanolic media by direct precipitation from ionic precursors, and analysed utilising a range of different techniques. The data suggest that this additive-free type of ACC does not resemble clear proto-structural motifs relating to any crystalline polymorph. This can be explained by the undefined pH value in iso-propanolic media, and the virtually instantaneous precipitation. Altogether, this work suggests that aqueous systems and pathways involving pre-nucleation clusters are required for the generation of clear proto-structural features in ACC. Experiments on the ACC-to-crystalline transformation in solution with and without ethanol highlight that polymorph selection is under kinetic control, while the presence of ethanol can control dissolution re-crystallisation pathways.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [2] ;  [3] ;  [1]
  1. Univ. of Konstanz (Germany)
  2. Dalhousie Univ. (Canada)
  3. Stockholm Univ. (Sweden)
Publication Date:
OSTI Identifier:
1214327
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
CrystEngComm (Online)
Additional Journal Information:
Journal Name: CrystEngComm (Online); Journal Volume: 17; Journal Issue: 26; Journal ID: ISSN 1466-8033
Publisher:
Royal Society of Chemistry
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY