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High‐Magnesium Calcite Mesocrystals: Formation in Aqueous Solution under Ambient Conditions
Author(s) -
Yu PaoTao,
Tsao Chieh,
Wang ChunChieh,
Chang ChunYu,
Wang ChiaHsin,
Chan Jerry Chun Chung
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201708507
Subject(s) - calcite , nucleation , dissolution , aqueous solution , amorphous solid , magnesium , amorphous calcium carbonate , chemical engineering , phase (matter) , chemistry , calcium carbonate , selected area diffraction , mineralogy , inorganic chemistry , materials science , transmission electron microscopy , crystallography , organic chemistry , engineering
Mesocrystals of high‐magnesian calcites are commonly found in biogenic calcites. Under ambient conditions, it remains challenging to prepare mesocrystals of high‐magnesian calcite in aqueous solution. We report that mesocrystals of calcite with magnesium content of about 20 mol % can be obtained from the phase transformation of magnesian amorphous calcium carbonate (Mg‐ACC) in lipid solution. The limited water content on the Mg‐ACC surface would reduce the extent of the dissolution–reprecipitation process and bias the phase transformation pathway toward solid‐state reaction. We infer from the selected area electron diffraction patterns and the dark‐field transmission electron microscopic images that the formation of Mg‐calcite mesocrystals occurs through solid‐state secondary nucleation, for which the phase transformation is initiated near the mineral surface and the crystalline phase propagates gradually toward the interior part of the microspheres of Mg‐ACC.