Apatite Formation: Why It May Not Work as Planned, and How to Conclusively Identify Apatite Compounds

Figure 4

Characteristic FTIR spectra (400–1500 cm⁻¹ range) for a well-crystallized stoichiometric hydroxyapatite (HA), a nanocrystalline apatite (matured 1 day, freeze dried), octacalcium phosphate (OCP), amorphous calcium phosphate (ACP), monetite (DCPA), and brushite (DCPD).