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Published online by Cambridge University Press: 29 February 2012
Calcium carbonate crystals were prepared via a simple precipitation reaction of sodium carbonate with calcium chloride from mixed solutions of various amphiphilic organic solvents and water in the presence of cetyltrimethylammonium bromide at 25 and 60 °C. Our analysis shows that amphiphilic organic solvents and temperature have large influences on the structure and morphology of CaCO3. X-ray diffraction patterns show that single-phase hexahedral calcite was formed at 25 °C, and orthorhombic aragonite was obtained at 60 °C. Mixtures of major amounts of long aragonite crystals and minor amounts of calcite particles were also obtained at 60 °C in the methanol and the acetone solutions. Scanning electron microscopy images show that CaCO3 particles and aggregates with various morphologies, such as large solid and hollow hexahedral crystals and small round granules of calcite as well as glass-like and wheat-like aggregates of aragonite, were obtained depending on the experimental conditions. Based on the experimental results, a conclusion on the effects of temperature and amphiphilic organic solvents on the crystal structure and morphology are made.