Preliminary Evaluation of Local Structure and Speciation of Lanthanoids in Aqueous Solution, Iron Hydroxide, Manganese Dioxide, and Calcite using the L3-Edge X-Ray Absorption Near Edge Structure Spectra.
Preliminary Evaluation of Local Structure and Speciation of Lanthanoids in Aqueous Solution, Iron Hydroxide, Manganese Dioxide, and Calcite using the L3-Edge X-Ray Absorption Near Edge Structure Spectra.
复制标题
使用 L3 边缘 X 射线吸收近边缘结构光谱初步评估水溶液、氢氧化铁、二氧化锰和方解石中的镧系元素的局部结构和形态。
DOI：
10.1021/acs.jpca.8b06168
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
H.
中科院分区：
文献类型：
--
作者：
Ohta;A.;Tanaka;K. and Tsuno;H.
我们阐明了应用L3边X射线吸收近边结构（XANES）光谱的镧系元素在水溶液中，氢氧化铁，二氧化锰，碳酸钙的局部结构分析。镧系元素化合物的L3边XANES谱显示出尖锐的白色谱线。镧系水离子的半峰全宽（FWHM）值在整个镧系的系列变化中表现出一个凸的四分体曲线。这种变化可归因于4f电子轨道，并可以用精细的自旋对能量理论来解释。对于每个镧系元素，镧系元素化合物的半高宽值大致随局部配位数的增加而减小。然而，它们不能忠实地反映镧系元素络合物的局部配位球，具有高的和扭曲的配位球，并且对它们的化学形式相当敏感。FWHM值的大小之间的关系由晶体场分裂或5d轨道的简并度决定。FWHM的系统性变化可以通过引起晶体场分裂的配体分子（− H2O 0、−O-、−OH-、− CO 32-、−Cl-和−O2-）的配体强度来解释。因此，镧系元素化合物的L3边XANES的半高宽值可能更适用于形态分析而不是结构分析。
We elucidate the application of L3-edge X-ray absorption near edge structure (XANES) spectra to the local structural analysis of lanthanoids in aqueous solution, iron hydroxide, manganese dioxide, and calcium carbonate. The L3-edge XANES spectra of lanthanoid compounds showed sharp white lines. The full width at half-maximum (FWHM) values of lanthanoid aqua ions exhibited a convex tetrad curve in the series variation across the lanthanoid series. The variation is attributable to 4f electron orbitals and can be explained by the refined spin-pairing energy theory. For each lanthanoid, the FWHM values of lanthanoid compounds roughly decreased with increasing local coordination numbers. However, they did not faithfully reflect the local coordination sphere of the lanthanoid complex having a high and distorted coordination sphere and were rather sensitive to their chemical forms. The relationship between the magnitude of the FWHM values was determined by the crystal field splitting or degeneracy of 5d orbitals. The systematic variation of FWHM can be explained by the ligand strength of the ligand molecules (−H2O0, −O–, −OH–, −CO32–, −Cl–, and −O2–) that cause the crystal field splitting. Therefore, the FWHM values of L3-edge XANES of lanthanoid compounds may be more useful in speciation analysis rather than structural analysis.