Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, RJ, Brazil.
Phys Chem Chem Phys. 2010 Dec 21;12(47):15490-500. doi: 10.1039/c0cp01032d. Epub 2010 Oct 25.
Substitution of cadmium into bulk hydroxyapatite Ca((10-x))Cd(x)(PO(4))(6)(OH)(2) (CdHA: x = 0.12, 1.3, 2.5) is studied by combining X-ray diffraction data from synchrotron radiation, Fourier transform infra-red spectroscopy (FTIR) and density functional theory (DFT) calculations. Energetic and electronic analyses are carried out for several configurations of Cd substitution for Ca at both cationic sites. Rietveld analysis shows preferential occupation of the Ca2 site by cadmium. FTIR data suggest a non-negligible covalent character of Cd-OH. The much-discussed cation site preference for substitution is determined on the basis of relaxed-lattice energetics, and interpreted in terms of chemical concepts; theory indicates that the Ca2 site is clearly favored and this preference is related to the more covalent character of this site compared to that of site 1.
通过结合来自同步加速器辐射的 X 射线衍射数据、傅里叶变换红外光谱（FTIR）和密度泛函理论（DFT）计算，研究了将镉替代大量羟基磷灰石 Ca((10-x))Cd(x)(PO(4))(6)(OH)(2)（CdHA：x = 0.12、1.3、2.5）中的情况。对几种 Cd 替代 Ca 在阳离子位置的配置进行了能量和电子分析。Rietveld 分析表明 Cd 优先占据 Ca2 位。FTIR 数据表明 Cd-OH 具有不可忽略的共价性质。根据弛豫晶格能确定了备受讨论的阳离子位置替代偏好，并根据化学概念进行了解释；理论表明，Ca2 位明显受到青睐，这种偏好与该位相对于 1 位的更共价性质有关。
