Isomorphous Substitutions of Rare Earth Elements for Calcium in Synthetic Hydroxyapatites
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- 作者：Lyudmyla I. Ardanova ; Evgeni I. Get’ ; man ; Stanislav N. Loboda ; Vadim V. Prisedsky ; Tatiana V. Tkachenko ; Valeriy I. Marchenko ; Valeriy P. Antonovich ; Nataliya A. Chivireva ; Konstantin A. Chebishe
- 刊名：Inorganic Chemistry
- 出版年：2010
- 出版时间：November 15, 2010
- 年：2010
- 卷：49
- 期：22
- 页码：10687-10693
- 全文大小：800K
- 年卷期：v.49,no.22(November 15, 2010)
- ISSN：1520-510X
文摘
Polycrystalline hydroxyapatites Ca10−<i>xi>REE<i>xi>(PO4)6(OH)2−<i>xi>O<i>xi> were synthesized and studied by X-ray powder diffraction, infrared absorption, diffuse-reflectance spectroscopy, and thermogravimetry. The solubility limits <i>xi>max of rare earth elements (REE) in Ca hydroxyapatites decreases with an increasing REE atomic number from <i>xi>max = 2.00 for La, Pr, and Nd to <i>xi>max = 0.20 for Yb at 1100 °C. Refinements of X-ray diffraction patterns by the Rietveld method show that REE atoms substitute for Ca preferentially at the Ca(2) sites of the apatite structure. The substitution decreases the Ca(2)−O(4) atomic distances in the calcium coordination polyhedra and increases the Ca(2)−O(1,2,3) distances. This observation shows that interatomic distances depend not only on radii of the ions involved in the substitution but also on their charges.