Syntheses, powder neutron diffraction structures and Mössbauer studies of some complex iron oxyfluorides: Sr3Fe2O6F0.87, Sr2FeO3F and Ba2InFeO5F0.68

Case, G. S.; Hector, Andrew L.; Levason, William; Needs, Richard L.; Thomas, Michael F.; Weller, Mark T.

doi:10.1039/a905730g

Cited by 50 publications

(46 citation statements)

References 23 publications

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“…The precursor crystallizes in the tetragonal structure with I4/mmm, but the fluorine insertion lowers the crystal symmetry to orthorhombic symmetry (Pbam), which is associated with rotation and tilting of the RuO 6 octahedra. The magnetic properties also change after the fluorination reaction, from the ferromagnetic state with T C = 105 K to weak ferromagnetic state with T N = 185 K. Fluorination of the RP-Ba 2−x Sr x PdO 3 (0 ≤ x ≤ 1.5) by PVDF involves unusual oxygen displacement through anion exchange [31,32], which is different from the case of the fluorination of Sr 3 Fe 2 O 6 described above [17]. As shown in Figure 8 …”

Section: Fluorine Insertion Into Only Interstitial Sites Between the mentioning

confidence: 92%

“…Subsequently, the same authors reported an isostructural iron oxyfluoride, Sr 2 FeO 3 F [16] and determined the crystal structure to be I4/mmm. However, Weller and his collaborators demonstrated that the exact crystal symmetry could be described as P4/nmm [17]. In contrast to K 2 NbO 3 F, the Fe counterpart possesses the O/F site order at the apical sites leading to a strong distortion of the FeO 5 F octahedron (see Figure 2(b)).…”

Section: Regular or Random Anion Occupation Pattern In The Perovskitementioning

confidence: 99%

“…For example, the fluorine contents incorporated by XeF 2 in YBa 2 Cu 3 O 7−δ increase with decreasing the oxygen deficient contents [45]. The fluorination of perovskite SrFeO 3 using PVDF yields SrFeO 2 F while the reaction of brownmillerite Sr 2 Fe 2 O 5 with F 2 gas results in the formation of two cubic phases different from SrFeO 2 F [17,46].…”

Section: Highly Fluorinated Iron Oxidesmentioning

confidence: 99%

“…This fluorination proceeds in a topotactic manner; the framework of the precursor is maintained through the reaction. While ASrNb 2 O 6 F and RbLnTiNbO 6 For n = 2 RP-type layered perovskite, Ba 3 In 2 O 5 F 2 [22] and Sr 3 Fe 2 O 6 F 0.68 [17] are known. Common to both compounds, fluorine atoms occupy the terminal apical sites.…”

Section: Regular or Random Anion Occupation Pattern In The Perovskitementioning

confidence: 99%

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Oxyfluoride Chemistry of Layered Perovskite Compounds

2012

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Abstract:In this paper, we review recent progress and new challenges in the area of oxyfluoride perovskite, especially layered systems including Ruddlesden-Popper (RP), Dion-Jacobson (DJ) and Aurivillius (AV) type perovskite families. It is difficult to synthesize oxyfluoride perovskite using a conventional solid-state reaction because of the high chemical stability of the simple fluoride starting materials. Nevertheless, persistent efforts made by solid-state chemists have led to a major breakthrough in stabilizing such a mixed anion system. In particular, it is known that layered perovskite compounds exhibit a rich variety of O/F site occupation according to the synthesis used. We also present the synthetic strategies to further extend RP type perovskite compounds, with particular reference to newly synthesized oxyfluorides, Sr 2 CoO 3 F and Sr 3 Fe 2 O 5+x F 2−x (x ~ 0.44).

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Section: Fluorine Insertion Into Only Interstitial Sites Between the mentioning

confidence: 92%

Section: Regular or Random Anion Occupation Pattern In The Perovskitementioning

confidence: 99%

Section: Highly Fluorinated Iron Oxidesmentioning

confidence: 99%

Section: Regular or Random Anion Occupation Pattern In The Perovskitementioning

confidence: 99%

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Oxyfluoride Chemistry of Layered Perovskite Compounds

2012

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“…However, 57 Fe Mössbauer spectroscopy has suggested [15−20] the disproportionation of Fe 4+ into Fe 3+ and Fe 5+ . Fluorination of this system has also been examined [21] by reducing Sr3Fe2O7-x to Sr3Fe2O6 and treating with gaseous fluorine to give Sr3Fe2O6F0.87 which also contained Fe 3+ and Fe 5+ . Subsequently [22] a higher degree of fluorine content was achieved in a material of composition Sr3Fe2O5.44F1.56 in which all the normal anion sites were filled by using polytetrafluoroethylene (PTFE) as the fluorination agent.…”

Section: Sr3fe2o5+xf2-xmentioning

confidence: 99%

Perovskite-Related Oxide Fluorides: The Use of Mössbauer Spectroscopy in the Investigation of Magnetic Properties

Berry¹,

Greaves²,

Gurusinghe³

et al. 2015

Croat. Chem. Acta

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Abstract:We review here some of our recent work on the synthesis and characterisation of new perovskite-related oxide fluorides. We demonstrate the use of low temperature fluorination methods for the preparation of new phases with high fluorine contents. We also show how fluorine can be accommodated in different sites according to the structural details of the initial oxide and the fluorine content. Importantly, we describe how Mössbauer spectroscopy is a powerful technique for monitoring changes in cation oxidation state as a result of fluorination and for examining the complex magnetic interactions which result from the accommodation of fluorine within the structures and how these can be related to structural properties and changes to the superexchange pathways.

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Topochemical Manipulation of Perovskites: Low‐Temperature Reaction Strategies for Directing Structure and Properties

et al. 2011

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Topochemical reaction strategies offer an important low-temperature (<500 °C) approach to the conscious manipulation of various inorganic host materials, allowing access to compounds that cannot be prepared by standard high-temperature methods. As the utility of these strategies continues to expand, researchers will be able to more effectively target materials with technologically significant properties. This Progress Report presents recent advances in topochemical reaction strategies as applied to perovskite and perovskite-related compounds. Emphasis is placed on structural modifications and corresponding variations in properties. Additionally, the future prospects of this approach to the rational design of intricate target compounds are discussed.

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Syntheses, powder neutron diffraction structures and Mössbauer studies of some complex iron oxyfluorides: Sr3Fe2O6F0.87, Sr2FeO3F and Ba2InFeO5F0.68

Cited by 50 publications

References 23 publications

Oxyfluoride Chemistry of Layered Perovskite Compounds

Oxyfluoride Chemistry of Layered Perovskite Compounds

Perovskite-Related Oxide Fluorides: The Use of Mössbauer Spectroscopy in the Investigation of Magnetic Properties

Topochemical Manipulation of Perovskites: Low‐Temperature Reaction Strategies for Directing Structure and Properties

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