EPR STUDY OF CARBONATE DERIVED AND OZONIDE RADICALS IN CARBONATED APATITES SYNTHESIZED FROM AQUEOUS-SOLUTIONS

In this study, a series of Na+ and (CO3(2-))-C-12 containing apatites synthesized by a hydrolysis of octo-calciumphosphate (OCP) and dried a t 25-degrees-C until constant weight, were examined with EPR after X-i rradiation. A variety of different paramagnetic radicals was formed, g iving rise to composite and hence complex EPR powder spectra. The spec tra were successfully decomposed into their basic components using a m ultivariate statistical technique. The different components could be i dentified unambiguously. In this way, it was found that an O-, an O-, a CO3-, two types of CO2- and two types of CO3(3-) ions were formed up on X-irradiation. Also resonances from atomic hydrogen were observed. The most striking feature is the presence of the ozonide ion, which is only rarely observed in irradiated hydroxyapatites. A comparison is m ade between the EPR spectra of apatite samples prepared by, hydrolysis of OCP on the one hand, and those of samples prepared by hydrolyzing monetite, and the tooth enamel spectrum on the other hand.