Figure 2. Solid-state ³¹P CP-MAS NMR spectra of MDP-HAp and reference samples. (a,b) Solid-state ³¹P CP-MAS NMR spectra of MDP-HAp samples, CaMHP₂, and HAp, together with a liquid NMR spectrum of MDP. For comparison, the ³¹P CP-MAS NMR spectrum of CaHPO₄·2H₂O is also shown. (c) ³¹P CP-MAS NMR spectra of MDP- HAp in ethanol and of HAp.