Mise en évidence d'un constituant de type «rouilles vertes» dans les sols hydromorphes. Proposition de l'existence d'un nouveau minéral : la «fougérite»

The natural occurrence of green rusts in soils is demonstrated for the first time on the basis of the simultaneous study of the reactivity and the structure of these compounds. A mixed Fe(ll)-Fe(lll) oxide transforms by oxidation into lepidocrocite and goethite, readily dissolves in the citrate-bicarbonate reagent without the necessity of a previous reduction, and shows Mossbauer and Raman spectra that enable us to identify it unambiguously as a green rust, by comparison with synthetic minerals.