Callens F J, Verbeeck R M, Naessens D E, Matthys P F, Boesman E R
Laboratory of Crystallography, State University Gent, Belgium.
Calcif Tissue Int. 1989 Feb;44(2):114-24. doi: 10.1007/BF02556470.
The ESR spectrum of X-irradiated carbonated apatites synthesized at low temperature was studied as a function of their carbonate content. Using 13C-enriched samples, four different carbonate-derived radicals and a surface O- ion could be identified. Isotropic CO3- and CO2- ions are present at a B site in the apatite lattice, and anisotropic CO3- and CO2- radicals are located at the surface of the crystallites. Only the isotropic ESR signals increase with increasing carbonate content. The anisotropic signal ascribed to a surface CO2- radical is mainly responsible for the so-called asymmetric ESR signal near g = 2. It is argued that this surface signal may still be composite and caused by several very similar CO2- ions. The consequences for phenomenological ESR studies of calcified tissues are discussed.
研究了低温合成的经X射线辐照的碳酸化磷灰石的电子自旋共振（ESR）谱与其碳酸盐含量的关系。使用富含13C的样品，可以识别出四种不同的源自碳酸盐的自由基和一个表面O-离子。各向同性的CO3-和CO2-离子存在于磷灰石晶格的B位，各向异性的CO3-和CO2-自由基位于微晶表面。只有各向同性的ESR信号随碳酸盐含量的增加而增加。归因于表面CO2-自由基的各向异性信号主要是造成g = 2附近所谓不对称ESR信号的原因。有人认为，这种表面信号可能仍然是复合的，由几个非常相似的CO2-离子引起。讨论了其对钙化组织现象学ESR研究的影响。
