Étude des mécanismes de formation des oxy-hydroxydes de fer ; hypothèses de transformations topotactiques
- 作者：Cudennec ; Yannick ; Lecerf ; André
- 关键词：Communication ; oxy-hydroxydes de fer ; g&oelig ; thite ; lé ; pidocrocite ; ré ; actions topotactiques ; iron oxy-hydroxides ; goethite ; lepidocrocite ; topotactic reactions
- 刊名：Comptes Rendus Chimie
- 出版年：2003
- 期刊代码：119_16310748
- 类别：ch
- 出版时间：April, 2003
- 卷：6
- 期：4
- 页码：437-444
- 文件大小：801 K
摘要
Study of the formation processes of iron oxy-hydroxides; hypotheses of topotactic transformations. Goethite α-FeO(OH) is the most stable iron oxy-hydroxide. It can be formed directly from trivalent iron solutions or from the ‘white rust’ (WR): Fe(OH)2, by oxidation of divalent iron. Nevertheless, another phase γ-FeO(OH), named lepidocrocite, can be obtained, at room temperature, in particular conditions of formation: fast oxidation of divalent iron in a precursor phase, named ‘green rust’ (GR), containing also trivalent iron and chloride ions. The formation of lepidocrocite from GR cannot be explained by a reconstructive transformation, which involves dissolution and re-crystallization. A structural study and a comparison of crystal structures of these different phases have been carried out. On the basis of that study, we propose three possible hypotheses of topotactic reactions: Formula Not Shown These transformations bring some explanations about the formation of iron oxy-hydroxides, which agree well with experimental results. To cite this article: Y. Cudennec, A. Lecerf, C. R. Chimie 6 (2003).