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Information × Registration Number 0204U000066, 0103U006129 , R & D reports Title The electron structure of point defects in apatite-like structures popup.stage_title Head Lytovchenko Anatoly Stepanovich, Registration Date 13-01-2004 Organization nstitute of Geochemistry, Mineralogy and Ore Formation popup.description2 Research objects were apatite and apatite-like bionanosystems. The work purpose was to establish the formation laws of the electronic structure of point defects and clusters in natural, synthetic and biogenic apatites and apatite-like systems. The research purpose on the 1st stage was to study of anionic replacement effects on parameters of point defects and structural and electrophysical characteristics of natural apatites. Research methods were electron paramagnetic resonance (EPR), proton magnetic resonance (PMR), IR-spectroscopy, luminescence and X-ray analysis. The classification of the paramagnetic centres and the luminescence centres in natural and synthetic apatites has been fulfiled. It is shown, that isomorphic replacements by the scheme F- - > OH-, Cl-, CO32- leads to essential changes of the spin-hamiltonian parameters of oxygen O- -centres, that indicates both changes of the centre geometrical characteristics and changes of chemical bond characters at these replacements. There have been experimentally investigated the effect of replacements by the scheme Ca2 + (F-, Cl-, OH-) -apatite - > Sr2 + (F-, Cl-, OH-) -apatite on parameters of hole O- - centres in such structures and structure features of the carbonate centres in biosystems. At the first there have been identified O23 - centres in the structure of synthetic apatite annealed at 1000 оС and higher. It has been shown, that the EPR signal intensity of this centre correlated directly with the tetracalciumphosphate phase amount. It is supposed, that nanodimensional TetCP phases or this phase nuclea are present in high-temperature apatites, which can be revealed by EPR. The investigation results can be used in physics and chemistry of solids, science of materials, mineralogy and medicine. Product Description popup.authors popup.nrat_date 2020-04-02 Close