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              2019.01.25 Science: Calcium carbonate

              A hydrated crystalline calcium carbonate phase: Calcium carbonate hemihydrate

              Hydrous CaCO3 gets a new structure

              Calcium carbonate (CaCO3) forms important minerals on Earth and is a model system for understanding crystal nucleation. Three different structures of CaCO3 are known, along with two structures that are hydrated. Zou et al. found a third hydrated CaCO3 structure formed from amorphous CaCO3 in the presence of magnesium ions. The discovery illustrates the importance of amorphous precursors for producing new materials.


              As one of the most abundant materials in the world, calcium carbonate, CaCO3, is the main constituent of the skeletons and shells of various marine organisms. It is used in the cement industry and plays a crucial role in the global carbon cycle and formation of sedimentary rocks. For more than a century, only three polymorphs of pure CaCO3—calcite, aragonite, and vaterite—were known to exist at ambient conditions, as well as two hydrated crystal phases, monohydrocalcite (CaCO3·1H2O) and ikaite (CaCO3·6H2O). While investigating the role of magnesium ions in crystallization pathways of amorphous calcium carbonate, we unexpectedly discovered an unknown crystalline phase, hemihydrate CaCO3·½H2O, with monoclinic structure. This discovery may have important implications in biomineralization, geology, and industrial processes based on hydration of CaCO3.

              Zhaoyong Zou
              Wouter J. E. M. Habraken
              Galina Matveeva
              Anders C. S. Jensen
              Luca Bertinetti
              Matthew A. Hood
              Chang-yu Sun
              Pupa U. P. A. Gilbert
              Iryna Polishchuk
              Boaz Pokroy
              Julia Mahamid
              Yael Politi
              Steve Weiner
              Peter Werner
              Sebastian Bette
              Robert Dinnebier
              Ute Kolb
              Emil Zolotoyabko
              Peter Fratzl

               1Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.

               2Johannes Gutenberg-Universität Mainz, Institut für Anorganische und Analytische Chemie, Mainz, Germany.

               3Department of Physics, University of Wisconsin–Madison, Madison, WI, USA.

               4Departments of Chemistry, Geoscience, and Materials Science, University of Wisconsin–Madison, Madison, WI, USA.

               5Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa, Israel.

               6Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany.

               7Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.

               8Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.

               9Max Planck Institute of Microstructure Physics, Halle, Germany.

               10Max Planck Institute for Solid State Research, Stuttgart, Germany.

               11Institute of Applied Geosciences, TU Darmstadt, Darmstadt, Germany

              †Corresponding author. Email: fratzl@mpikg.mpg.de
              * Present address:
              State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,
              Wuhan University of Technology, Wuhan, China.
              Science  25 Jan 2019:
              Vol. 363, Issue 6425, pp. 396-400
              DOI: 10.1126/science.aav0210

              Welcome to

               The 11th International Symposium on Nano & Supramolecular Chemistry (ISNSC-11)
              The 3rd World Forum on Industrial Minerals (WFIM-3)

              Qing Yang  (Jiu Hua Shan), Chi Zhou City, China
                October 12-16, 2019

              Theme: Fusion of Supramolecular Chemistry, Nanotechnology and Industrial Mineralogy
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