Fig. 1: Microstructural features of vaterite.

a Splitting of the most intense Raman band ν₁. The best result of the Gaussian fitting procedure was achieved for the decomposition of three peaks at 1075 cm⁻¹, 1080 cm⁻¹ and 1091 cm⁻¹. b HAADF image showing the laminate structure. The inset shows the morphological features of the pearls with vaterite structure. Scale bar = 500 nm. c HRTEM image of vaterite. Inset is the corresponding FFT pattern. Streaking features in inset FFT patterns indicate the representative stacking feature in vaterite structure. Scar bar = 10 nm.