Concerning the β phase of iron(III) oxide

Ben‐Dor, L.; Fischbein, E.; Kálmán, Z. H.

doi:10.1107/s0567740876003749

Cited by 36 publications

(22 citation statements)

References 2 publications

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“…It has an orthorhombic structure and is ferromagnetic with T C = 480 K 6,10 . β-phase is another new phase having a bixbyite structure and exhibits antiferromagnetic feature with a Neel temperature (T N ) of 119 K [11][12][13] . α-Fe 2 O 3 is the thermodynamically most stable among these four polymorphs.…”

mentioning

confidence: 99%

Crystallization and magnetic property of iron oxide nanoparticles precipitated in silica glass matrix

Masubuchi

Sato

Sawada

et al. 2011

Journal of the European Ceramic Society

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confidence: 99%

Crystallization and magnetic property of iron oxide nanoparticles precipitated in silica glass matrix

Masubuchi

Sato

Sawada

et al. 2011

Journal of the European Ceramic Society

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“…1. There is the formation of the cubic phase of Fe 2 O 3 [12] after 200°C that still remains in a small concentration at 400°C, noticed by the peak near 38°. The vertical bars denote the cubic phase as predicted by cubic symmetry.…”

Section: Resultsmentioning

confidence: 90%

Sintering of nanoparticles of α-Fe2O3 using gelatin

Menezes

Remédios

Sasaki

et al. 2007

Journal of Non-Crystalline Solids

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“…The Zboril et al (1999) study is closely related to the present study in that they prepared b-Fe 2 O 3 by heating Fe 2 (SO 4 ) 3 above 500°C. The phase b-Fe 2 O 3 is cubic, Ia3, with a = 9.404 Å (Ben-Dor et al 1976). In the present study, the a cell parameter was found to decrease with increasing temperature, from 9.465(1) Å at 600°C to 9.447(1) Å at 680°C.…”

Section: From 400 To 500°cmentioning

confidence: 99%

In Situ XRD Study of the Thermal Decomposition of Natural Arsenian Plumbojarosite

Mills¹,

Grey²,

Birch³

2009

The Canadian Mineralogist

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The thermal decomposition of arsenian plumbojarosite, Pb 0.59 Fe 3 (AsO 4 ) 0.18 (SO 4 ) 1.82 (OH) 6 , from the Lomo Deltoro mine, Mexico, has been studied using in situ X-ray powder diffraction, combined with thermogravimetric and chemical analyses. The minor arsenic becomes enriched in the crystalline products of decomposition as SO 3 is evolved during heating, and it eventually controls the phases that form. Dehydroxylation at 400°C produces an initially amorphous product from which metastable nanocrystalline b-PbSO 4 and b-Fe 2 O 3 crystallize. With an increasing size of crystallites, these transform to the stable anglesite (incorporating As) and hematite phases. Above 620°C, the arsenian anglesite incorporates Na and Fe from the amorphous component and transforms to a cubic eulytine-type phase, Pb 5 Na 2 Fe(AsO 4 ) 3 (SO 4 ) 3 , plus PbO (litharge). At temperatures in the range 720 to 760°C, the eulytine phase and PbO react to form an apatite-type phase, Pb 5 (AsO 4 ) 2 (SO 4 )O, via an intermediate partially amorphous phase region. The phase assemblage of Pb 5 (AsO 4 ) 2 (SO 4 )O plus hematite is stable to about 860°C, where partial melting occurs. Above 860°C, hematite coexists with an amorphous phase and poorly crystalline lanarkite, Pb 2 O(SO 4 ).Keywords: arsenian plumbojarosite, Lomo Deltoro mine, Mexico, thermogravimetric analysis, in situ powder X-ray diffraction, Rietveld quantitative phase-analysis, amorphous phases, metastable phases. SoMMaIreNous avons documenté la décomposition thermique de la plumbojarosite arsenifère, Pb 0.59 Fe 3 (AsO 4 ) 0.18 (SO 4 ) 1.82 (OH) 6 , provenant de la mine Lomo Deltoro, au Mexique, en employant la diffraction X in situ sur poudre et les résultats d'analyses thermogravimétriques et chimiques. L'arsenic, composant mineur au départ, devient progressivement concentré dans les produits cristallins de décomposition à mesure que le SO 3 produit par chauffage s'échappe, et il régit éventuellement les phases qui apparaissent. La déshydroxylation à 400°C produit au départ une phase amorphe à partir de laquelle se forment de façon métastable des nanocristaux de b-PbSO 4 et b-Fe 2 O 3 . A mesure que la taille de ces cristallites augmente, ceux-ci se transforment en anglésite (avec incorporation de l'arsenic) et hématite stables. Au delà de 620°C, l'anglésite arsenifère incorpore le Na et le Fe provenant du composant amorphe et se transforme en une phase cubique de type eulytine, Pb 5 Na 2 Fe(AsO 4 ) 3 (SO 4 ) 3 , avec PbO (litharge). A températures dans l'intervalle de 720 à 760°C, la phase de type eulytine réagit avec le PbO pour former une phase du groupe de l'apatite, Pb 5 (AsO 4 ) 2 (SO 4 )O, via une phase intermédiaire partiellement amorphe. L'assemblage Pb 5 (AsO 4 ) 2 (SO 4 )O + hématite est stable jusqu'à environ 860°C, le point de fusion du mélange. Au-delà de 860°C, l'hématite coexiste avec une phase amorphe et la lanarkite, Pb 2 O(SO 4 ), à faible cristallinité. (Traduit par la Rédaction)Mots-clés: plumbojarosite arsenifère, mine Lomo Deltoro, Mexique, analyse the...

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Concerning the β phase of iron(III) oxide

Abstract: fl-Fe203, body centred cubic, la3, a0=9"393 (2) A, Z= 16, D~,= 5"14 g cm -a. In the 24(d) and 8(b) symmetry positions the Fe 3+ ions are octahedrally coordinated, the former being more distorted than the latter.

Cited by 36 publications

References 2 publications

Crystallization and magnetic property of iron oxide nanoparticles precipitated in silica glass matrix

Crystallization and magnetic property of iron oxide nanoparticles precipitated in silica glass matrix

Sintering of nanoparticles of α-Fe2O3 using gelatin

In Situ XRD Study of the Thermal Decomposition of Natural Arsenian Plumbojarosite

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