Ambient Formation of Spherulites of Mg-Calcite in an Aqueous Lipid Solution through the Interplay between Multiple Pathways
C. H. Tsao, Pao‐Tao Yu, Shuli Li, I‐Jui Hsu, Yu‐Chun Chuang, Chung‐Kai Chang, Shiang‐Jiuun Chen, Jerry C. C. Chan
Abstract
Nanograins of Mg-containing amorphous calcium carbonate were prepared in an l-α-lecithin solution from which spherulitic crystallites of high-Mg calcite were subsequently formed. The structures of the spherulites of high-Mg calcite were carefully characterized using powder X-ray diffraction, electron microscopy, and solid-state NMR spectroscopy. While the initial growth of Mg-calcite spherulites occurs through the particle attachment pathway, the process of ion-by-ion addition appears to be the predominant mechanism of formation near the end stage of the crystal growth. Consequently, the outer region of the Mg-calcite spherulites displays a higher crystallinity than the inner region, which is a direct consequence of the interplay between multiple pathways.