MENTRÉ, Olivier; BLAZQUEZ-ALCOVER, Ignacio; GARCÍA-MARTÍN, Susana; DUTTINE, Mathieu; WATTIAUX, Alain; PARDIS, Simon; HUVÉ, Marielle; DAVIERO-MINAUD, Sylvie

doi:10.1021/acs.inorgchem.8b02122

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MENTRÉ, Olivier
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]

BLAZQUEZ-ALCOVER, Ignacio
Unité de Catalyse et Chimie du Solide - UMR 8181 [UCCS]

GARCÍA-MARTÍN, Susana
Departemento Química Inorgánica

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Ce document a été publié dans

Inorganic Chemistry. 2018-12-04, vol. 57, n° 24, p. 15093-15104

American Chemical Society

Résumé en anglais

The mixed-valent iron arsenate hydroxide Fe13.52.22+(AsO4–x)8(OH)6, x = 0.25, was prepared using the reaction of iron metal with arsenate in aqueous solution and autogenous pressure. Its crystal structure reveals a dumortierite-like framework with mixed-valent Fe2+/Fe3+ in double chains creating channel walls. Remarkably, hexagonal channels consist of chains of face-sharing Fe2+O6 octahedra, 3/4th occupied, whereas AsO4 tetrahedra occupy triangular ones with a single “up” orientation according to the polar P63mc symmetry. We have analyzed the transformation of this phase upon heating, in which several chemical processes interact, including dehydroxylation, arsenate to arsenite reduction, and oxidative exsolution of a significant part of iron (ca. 15%) found at the surface as hematite and amorphous Fe-rich surficial layer. It leaves a strongly disordered composite structure between several Fe3+-based subunits, in which ∼80% of them is ordered in a complex supercell. Because of the high degree of disorder, the crystal chemistry of the individual subunits and their plausible imbrication were considered to unravel the most plausible ideal 3D model.< Réduire

DOI

http://dx.doi.org/10.1021/acs.inorgchem.8b02122

Project ANR

Couplages Magnéto-Electriques exacerbés dans des matériaux à unités ferromagnétiques - ANR-16-CE08-0023

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Importé de hal

Unités de recherche

Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB) - UMR 5026