Systematic trends of the 57Fe Mössbauer isomer shifts in (FeOn) and (FeFn) polyhedra. Evidence of a new correlation between the isomer shift and the inductive effect of the competing bond T-X (→ Fe) (where X is O or F and T any element with a formal positive charge)

Ménil, Francis

doi:10.1016/0022-3697(85)90001-0

Cited by 668 publications

(277 citation statements)

References 221 publications

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“…[36] The exchange reaction was achieved exactly in the same way as for lanthanide salts and the resulting material was called X1 . These values are in accordance with Mçssbauer parameters commonly associated with six coordination Fe 3 + complexes, [37,38] as the usual isomer shift values for Fe III are: 0.10-0.30 mm s À1 for Fe III in tetrahedral site and 0.28-0.50 mm s…”

Section: Exchange Reaction With Fecl 3 (Mçssbauer Spectroscopy)supporting

confidence: 77%

Selective Lanthanides Sequestration Based on a Self‐Assembled Organosilica

Besson

Mehdi

Lee

et al. 2010

Chemistry A European J

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In this paper, we investigate the cation-exchange properties of a self-assembled hybrid material towards trivalent ions, lanthanides (La(3+), Eu(3+), Gd(3+), Yb(3+)) and Fe(3+). The bis-zwitterionic lamellar material was prepared by sol-gel process from only 3-aminopropyltriethoxysilane (APTES), succinic anhydride, and ethylenediamine. In ethanol heated under reflux, the exchange ethylenediammonium versus Ln(3+) proved to be complete by complexometry measurements and elemental analyses, one Cl(-) ion per one Ln(III) remaining as expected for charge balance. In aqueous solution at 20 degrees C, the material was found to be selective towards lanthanide in spite of the similarity of their ionic radii. The cation uptake depends on the nature of the salt, the difference between two lanthanides reaching up to 20 % in some cases. Finally, ion-exchange reaction with FeCl(3) was chosen as a probe to get more information on the material after incorporation of trivalent ions. Based on Mössbauer spectroscopic investigations on the resulting material in conjunction with the XRD analysis of materials containing trivalent ions, a structural model was proposed to describe the incorporation of trivalent ions by exchange reaction within the original zwitterionic material.

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Section: Exchange Reaction With Fecl 3 (Mçssbauer Spectroscopy)supporting

confidence: 77%

Selective Lanthanides Sequestration Based on a Self‐Assembled Organosilica

Besson

Mehdi

Lee

et al. 2010

Chemistry A European J

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“…The 57 [41]. Our calculations of the main components {V ii } i = x,y,z of the EFG tensor V lat , using crystal data for the high-temperature rhombohedral [42] and low-temperature (T < T N2 )…”

Section: A Paramagnetic Temperature Range (T > T N1 )mentioning

confidence: 99%

⁵⁷Fe Mössbauer study of unusual magnetic structure of multiferroic 3R-AgFeO₂

Sobolev¹,

Rusakov²,

Moskvin³

et al. 2017

J. Phys.: Condens. Matter

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We report new results of a 57 Fe Mössbauer study of multiferroic 3R-AgFeO 2 powder samples performed in a wide temperature range, including two points, T N1 » 14 K and T N2 » 9 K, of magnetic phase transitions. At the intermediate temperature range, T N2 < T < T N1 , the 57 Fe Mössbauer spectra can be described in terms of collinear spin-density-waves (SDW) with the inclusion of many high-order harmonics, indicating that the real magnetic structure of this ferrite appears to be more complicated than a pure sinusoidally modulated SDW. The spectra at low temperatures, T < T N2 , consist of a Zeeman pattern with line broadenings and sizeable spectral asymmetry. It has been shown that the observed spectral shape is consistent with a transition to the elliptical cycloidal magnetic structure. An analysis of the experimental spectra was carried out under the assumption that the electric hyperfine interactions are modulated when the Fe 3+ magnetic moment rotates with respect to the principal axis of the EFG tensor and emergence of the strong anisotropy of the magnetic hyperfine field H hf at the 57 Fe nuclei. The large and temperatureindependent anharmonicity parameter, m » 0.78, of the cycloidal spin structure obtained from the experimental spectra results from easy-axis anisotropy in the plane of rotation of the iron spin.Analysis of different mechanisms of spin and hyperfine interactions in 3R-AgFeO 2 and its structural analogue CuFeO 2 points to a specific role played by the topology of the exchange coupling and the oxygen polarization in the delafossite structures.

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“…При разложении спектров на составляющие компонен-ты принимали соотношения интенсивностей пиков I 1 : I 2 : I 3 = 3 : 2,2 : 1,1, как заложено в программе, и равенство по ширине каждого из секстетов. Интер-претацию валентных состояний ионов железа и ко-ординационных состояний проводили в соответствии с работой [9]. Наилучшими вариантами разложения спектров, измеренных при 300 К и обеспечивающих минимум χ 2 , были варианты, когда линии сверхтон-кой структуры раскладывались на 5 и 6 секстетов и два дублета, а при 90 К -на 9 секстетов и два ду-блета.…”

Section: образцы и методы исследованияunclassified