Original paper

The nontronite-saponite series: An experimental approach

Grauby, Olivier; Petit, Sabine; Decarreau, Alain; Baronnet, Alain

European Journal of Mineralogy Volume 6 Number 1 (1994), p. 99 - 112

49 references

published: Feb 4, 1994
manuscript accepted: Oct 11, 1993
manuscript received: Nov 30, 1992

DOI: 10.1127/ejm/6/1/0099

BibTeX file

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Abstract The study of the octahedral Fe-Mg substitution in smectites was conducted using clay synthesis at 200°C. Mossbauer data revealed that only ferric iron occurs in synthesized smectites. The studied series is then obviously heterovalent. All synthesized clays were tetrahedrally charged leading to structural formulae varying between nontronite and saponite end-members. According to XRD data, the b parameter increases continuously with Mg-contents, following a Vegard's law. AEM chemical analyses of isolated clay particles show a continuous evolution between the two end-members. However, IR data provide evidence for the segregation of octahedral cations in local dioctahedral and trioctahedral arrangements. The series is then a true continuous solid solution from nontronites to saponites, with differentiated octahedral clusters


synthesissolid solutionnontronitesaponiteditrioctahedral latticespectroscopic methods