Maghemite structure

In the case of roasting, the pretreatment process destroys the sulfide matrix by driving off sulfur from the structure. This results in the formation of iron oxide particles that are made of concentrically zoned and porous hematite and maghemite (Paktunc et al. 2006). Arsenic is volatilized as As203 and oxidised to... 

Maghemite (magnetite - hematite) has a structure similar to that of magnetite. It differs from magnetite in that all or most Fe is in the trivalent state. Cation vacancies... 

Leland and Bard (1987) found that the different iron oxides induced photooxidation of oxalate and sulphite at rates that varied by up to two orders of magnitude. For oxalate, the rate was greater for maghemite than for hematite, but this order was reversed for sulphite. Lepidocrocite (layer structure) induced faster oxidation of both compounds that did the other polymorphs of FeOOH (tunnel structures) the authors considered that the rate differences were probably associated with structural differences between the adsorbents. 

Single-crystalline maghemite (y-FezOs) nanotubes are obtained by a reduction and re-oxidation processes with hematite (a-FezOs) nanotubes as precursors. This approach provides a new strategy to synthesize single-crystalline nanotubes of nonlamellar-structured materials, which could be generally applicable to the synthesis of other inorganic tubular nanostructures. 

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