K-H3OFe3(SO4)2(OH)6铁矾的XRD研究

根据X射线衍射(XRD)分析发现: A Fe₃(SO₄)₂(OH)₆(A=K⁺、H₃O⁺)系列铁钒的XRD数据十分相近,难以用XRD区别,需通过能谱(EDS)辅助分析,才能区分此类铁矾。另外,此类铁矾的003和107面网间距d随K⁺含量增大而增大,且呈一元三次方程的关系;而033和220面网间距d随K⁺含量增大而减小,呈一元二次方程的关系。对该现象从铁矾晶体结构方面进行解释:K⁺、H₃O⁺离子位于较大空隙中,且沿着Z轴方向排列,当K⁺、H₃O⁺离子之间相互替换时,会导致该铁矾晶体结构在Z轴方向有较明显的变化。

XRD study of K-H3OFe3(SO4)2(OH)6 jarosite

X-ray diffraction analysis shows that it is difficult to discriminate various kinds of A Fe₃(SO₄)₂(OH)₆(A=K⁺, H₃O⁺) jarosites because their XRD data are very similar to each other. However, a series of jarosites could be discriminated by XRD and EDS method. The XRD result shows that 003 and 107 lattice spacing (d) of the jarosite increases with K⁺ ion content, whereas 033 and 220 lattice spacing (d) decreases with increasing K⁺ ion content. Their relationship is described by the regression equation. The explanation of this result from the crystal structure theory is that K⁺ and H₃O⁺ ions are located in the larger space and distributed along Z axis. Obvious change of jarosite crystal structure in the Z axis occurs with the mutual substitution between K⁺ and H₃O⁺ ions.