Template-free fabrication of single-crystalline calcite nanorings during crystal growth in water

Morphology evolution of calcite nanoparticles was investigated in detail during crystal growth induced by containing their aqueous slurry at a temperature of 95 °C. Formation of a single-crystalline nanoring that has a single cavity was confirmed soon after the slurry temperature was elevated to 95 °C. No templates were employed during the crystal growth process.