Local structure of hydroxy–peroxy apatite: A combined XRD, FT-IR, Raman, SEM, and solid-state NMR study

The synthesized hydroxyapatite (HAp) and hydroxy–peroxy apatite are studied using various techniques, such as X-ray powder diffraction, FT-IR and Raman spectroscopy, scanning electron microscopy, and solid-state NMR spectroscopy. The experimental data suggest that hydroxy–peroxy apatite contains a small amount of hydration of partially dehydroxylated hydroxyapatite phase and calcium hydroxide. The incorporation of peroxide ions into the lattice of HAp causes perturbations of the hydrogen environments and slight changes in its crystal morphology. The distance between H in some structural OH− and adjacent O along the c-axis becomes longer instead of forming a hydrogen bond after the incorporation of peroxide ions.