Pb3+ radiation defects in Ca9Pb(PO4)6(OH)2 hydroxyapatite nanoparticles studied by high-field (W-band) EPR and ENDOR

W-band pulsed EPR and ENDOR investigations of X-ray irradiated nanoparticles of synthetic hydroxyapatite Ca9Pb(PO4)6(OH)2 are performed. It is shown that in the investigated species lead ions probably replace the Ca(1) position in the hydroxyapatite structure.