Structural and 57Fe Mössbauer spectroscopic characterization of the synthetic NaFeSi2O6 (aegirine) – CaMgSi2O6 (diopside) solid solution series
Structural and 57Fe Mössbauer spectroscopic characterization of the synthetic NaFeSi2O6 (aegirine) – CaMgSi2O6 (diopside) solid solution series
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合成 NaFeSi2O6（aegirine）-CaMgSi2O6（透辉石）固溶体系列的结构和 57Fe 穆斯堡尔光谱表征
DOI：
10.1524/zkri.2012.1514
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
G. Roth
中科院分区：
文献类型：
--
作者：
G. Redhammer;G. Tippelt;G. Amthauer;G. Roth
摘要通过助熔剂法和高压实验，沿霓石-透辉石结合部沿着合成了单斜辉石。用57 Fe穆斯堡尔谱和单晶X射线衍射对样品进行了表征。讨论了配位、键长和键角以及多面体扭曲参数随组成的变化。所有样品均表现出C2/c空间群对称性，并显示出结构参数随化学性质的平滑变化。随着透辉石组分的增加，晶格常数a和B增加，c减小，即使较小的Fe 3+被较大的Mg 2+取代。从霓石到透辉石的八面体链中M1-M1阳离子距离明显减小，这表明随着M1阳离子电荷的减小，M1阳离子之间的排斥力减小是造成这种行为的原因。在57 Fe穆斯堡尔谱中，在高压实验的样品中检测到少量的Fe 2+。四极分裂的两个，Fe 2+和Fe 3+表明随着透辉石含量的增加，铁八面体的畸变增加，而M1网站的整体畸变减少。这表明，局部结构单元的行为可能与平均结构完全不同。
Abstract Clinopyroxenes along the aegrine – diopside join have been synthesized from flux growth and high pressure experiments. Samples were characterized by 57Fe Mössbauer spectroscopy and single crystal X-ray diffraction. Coordination, bond lenghts and – angles and polyhedral distortion parameters are discussed as a function of composition. All samples exhibit C2/c space group symmetry and show smooth variation of structural parameters with chemistry. While the lattice parameters a and b increase with increasing diopside component, c decreases, even if the smaller Fe3+ cation is replaced by the larger Mg2+ one. A distinctly decreasing M1—M1 cationic distance within the octahedral chain from aegirine to diopside suggests, that decreasing repulsive forces between M1 catäions with decreasing charge of the M1 cation is responsible for this behaviour. In 57Fe Mössbauer spectroscopy, small amount of Fe2+ were detected in the samples of the high pressure experiments. The quadrupole splitting of both, Fe2+ and Fe3+ suggests an increasing distortion of the Fe-octahedra with increasing diopside content, while the overall distortion of the M1 sites decrease. This shows that local structural units may behave quite differently as compared to the average structure.