Polarized infrared reflectance spectra of brushite (CaHPO4 2H2O) crystal investigation of the phosphate stretching modes

Polarized infrared (IR)reflectancemeasure ments at near-normal incidence were recorded from the ac-plane of amonoclinic brushite (CaHPO4 2H2O)crystal in the 800–1200cm 1spectral range (P–Ostretch- ing modes).The adjustment of these data,on the basis of adispersion analysis (DA)model for monoclinic case,allowed the determination of oscillators parameters for the four P–Ostretching observed modes of the phosphate group