The ikaite-to-vaterite transformation: new evidence from diffraction and imaging

摘要: Vaterite is one of three polymorphs calcium carbonate (CaCO3) found in nature, the others being calcite and aragonite. Here formation vaterite from decomposition ikaite (CaCO3·6H2O) was investigated using synchrotron powder diffraction scanning electron microscopy. The crystallite sizes (∼40 nm) were to be much smaller than those precursor (∼0.5–1.0 µm) as a result nucleating dehydrates. rate increases with temperature, indicating kinetic control this transformation. It postulated that structural arrangement hydration sphere around Ca2+ determines orientation CO32− ions such nucleates upon dehydration. This implies dehydration hydrated phase required for nucleation.