Water as the Key to Proto-Aragonite Amorphous CaCO3
Number of Authors: 5
2016 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 55, no 28, 8117-8120 p.Article in journal (Refereed) Published
Temperature and pH value can affect the short-range order of proto-structured and additive-free amorphous calcium carbonates (ACCs). Whereas a distinct change occurs in proto-vaterite (pv) ACC above 45 degrees C at pH 9.80, proto-calcite (pc) ACC (pH 8.75) is unaffected within the investigated range of temperatures (7-65 degrees C). IR and NMR spectroscopic studies together with EXAFS analysis showed that the temperature-induced change is related to the formation of proto-aragonite (pa) ACC. The data strongly suggest that the binding of water molecules induces dipole moments across the carbonate ions in pa-ACC as in aragonite, where the dipole moments are due to the symmetry of the crystal structure. Altogether, a (pseudo-)phase diagram of the CaCO3 polyamorphism in which water plays a key role can be formulated based on variables of state, such as the temperature, and solution parameters, such as the pH value.
Place, publisher, year, edition, pages
2016. Vol. 55, no 28, 8117-8120 p.
amorphous calcium carbonate, biomineralization, NMR spectroscopy, polyamorphism, water
IdentifiersURN: urn:nbn:se:su:diva-135063DOI: 10.1002/anie.201603176ISI: 000383253100044PubMedID: 27254155OAI: oai:DiVA.org:su-135063DiVA: diva2:1049623