Synthetic solid solutions between goethite and diaspore

Franz, E. D.

doi:10.1180/minmag.1978.042.321.31

Cited by 5 publications

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“…The formation of substitutional solid solutions between the isostructural goethite (a-FeOOH) and diaspore (a-A100H) is undoubtedly limited, but data on the solubility limits are very divergent. The replacement of iron by aluminium has been reported both in natural and synthetic goethites ( Norrish and Taylor, 1961;Janot and Gilbert, 1970;Mendelovici et al, 1979;Thiel, 1963;Jonas and Solymar, 1970;Franz, 1978;Schulze and Schwertmann, 1984).…”

Section: Introductionmentioning

confidence: 98%

Synthetic solid solutions formed between goethite and diaspore

Wolska

Szajda

Piszora

1992

J Plant Nutrition & Soil

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The substitutional solid solutions of goethite (a‐FeOOH) and diaspore (α‐AlOOH) have been investigated by X‐ray powder diffraction and chemical analysis in order to establish the solubility limits of aluminium in the goethite structure. α‐Fe1‐xAIxOOH samples were obtained by ageing of coprecipitated amorphous (Fe,Al) hydroxides at pH 13 in NaOH and Na[Al(OH)4] solutions at 25°C (G25 series) and 70°C (G70 series), respectively. Chemical analysis reveals that the aluminium content of Al goethites is consistent with Al concentration in the coprecipitated hydroxides up to about 10 mol% Al. In Al goethites obtained from (Fe,Al) hydroxides with higher Al:Fe ratios, the relative Al content is considerably lower. It was found that pure ferrihydrite stored in the aluminate solution is also transformed into Al goethite. The X‐ray diffraction results show a significant divergence of the unitcell parameters from Vegard's law. This points out the limited ranges of the solid solution between goethite and diaspore and suggests the formation of defect, cation‐deficient structures.

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