The crystallinity increases as the narrowing of the diffraction lines increases . Therefore, it is possible to affirm that the samples with a higher degree of crystallinity are H7-C, H8-C-EN, and H10-C-EN. . Interestingly, the hydroxyapatite nanoparticles obtained in the present work led to smaller crystallite sizes than in previous works. However, the simultaneous effects of the selected independent variables were not significant (see Table ).