Octahedral cation partitioning in Mg,Fe2+-olivine. Mossbauer spectroscopic study of synthetic (Mg0.5 Fe2+0.5)2SiO4(Fa50)

Morozov, M. V.; Brinkmann, Christian; Lottermoser, Werner; Tippelt, Gerold; Amthauer, Georg; Kroll, Herbert

doi:10.1127/0935-1221/2005/0017-0495

Cited by 36 publications

(22 citation statements)

References 16 publications

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“…In accordance with the results of Morozov et al (2005aMorozov et al ( , 2005b, quadrupole doublet with higher relative area was related to M1 site and the other doublet was related to M2 sites. Distributions of Fe 2+ ions between M1 and M2 sites in olivine obtained on the basis of relative areas of olivine components in Mössbauer spectra of chondrites are shown in Fig.…”

Section: Olivine and Pyroxenesupporting

confidence: 89%

“…The contrast of M1 and M2 sites geometry in olivine is less than that in pyroxene. Mössbauer spectroscopy was successfully used to distinguish M1 and M2 sites in pure synthetic and natural orthopyroxenes (Pasternak et al 1992;Van Alboom et al 1993;Wang et al 2005;Dyar et al 2007), clinopyroxenes (Eeckhout et al 2000;Eeckhout 2003a, 2003b), and olivines (Morozov et al 2005a(Morozov et al , 2005b. Nevertheless, there were no attempts to distinguish subspectra related to M1 and M2 sites in both olivine and pyroxene in Mössbauer spectra of ordinary chondrites except the study of extracted silicates (Gismelseed et al 2004).…”

Section: Introductionmentioning

confidence: 99%

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A study of ordinary chondrites by Mössbauer spectroscopy with high‐velocity resolution

Оштрах¹,

Petrova²,

Grokhovsky³

et al. 2008

Meteorit & Planetary Scien

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Abstract-An improvement in the velocity resolution and quality of Mössbauer spectra has been applied to a group of ordinary chondrites. This improvement permitted us to carry out a more detailed study of the iron bearing phases in these samples than has previously been possible. Mössbauer spectra of 11 ordinary chondrites of L and H chemical groups were measured using 4096 channels and presented for further analysis in 1024 channels. Subspectra of the metal grains of several chondrites demonstrated the presence of at least two magnetic sextets related to the main Fe(Ni, Co) phases. Moreover, Mössbauer study of extracted metal grains from Tsarev L5 revealed three sextets and one singlet spectral components related to various α-Fe(Ni, Co), α′-Fe(Ni, Co), α 2 -Fe(Ni, Co), and γ-Fe(Ni, Co) phases. Each subspectrum of olivine and pyroxene in Mössbauer spectra of ordinary chondrites was fitted by superposition of two quadrupole doublets related to M1 and M2 sites in minerals for the first time. An analysis of relative areas and Mössbauer hyperfine parameters was performed and some differences for L and H chondrites as well as for M1 and M2 sites were observed. Mössbauer parameters of troilite and oxidized iron were analyzed. In contrast to a previous study with 512-channel spectra, the presence of oxidized iron was found in all chondrites.

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Section: Olivine and Pyroxenesupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

A study of ordinary chondrites by Mössbauer spectroscopy with high‐velocity resolution

Оштрах¹,

Petrova²,

Grokhovsky³

et al. 2008

Meteorit & Planetary Scien

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“…In Fig. 3 we plot the variation of K D with temperature, together with the K D values for synthetic Fa50 obtained from in situ powder neutron diffraction experiments [6] and from Mössbauer spectroscopy on quenched synthetic Fa50 [7]. As can be seen from the figure, there is an agreement between our data and the neutron diffraction data at temperatures below ∼600 • C, where Fe 2+ orders at the M1 site.…”

Section: Methodssupporting

confidence: 66%

“…Such a trend of cation ordering was also observed in synthetic Fa50 studied by in situ neutron powder diffraction, with the crossover temperature being ∼600 • C [6]. However, recent Mössbauer measurements on synthetic Fa50, annealed at high temperature (500-800 • C) and quenched, showed an increase of order of Fe 2+ at the M1 site with increasing annealing temperature, in agreement with both quenched and in situ single-crystal X-ray diffraction experiments on natural olivines Fa12, Fa25, and Fa48 [7].…”

supporting

confidence: 78%

High-temperature cation ordering in olivine: an in situ Mössbauer study of synthetic (Mg0.55Fe0.45)2 SiO4

et al. 2008

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High-temperature in situ Mössbauer spectroscopy measurements (300-950 • C) were done on synthetic olivine of composition (Mg 0.55 Fe 0.45 ) 2 SiO 4 (=Fa45) in order to study the distribution of Fe 2+ over the M1 and M2 octahedral sites. The spectra are fit with two doublets, which are assigned to Fe 2+ at the M1 (smaller splitting) and M2 sites. The Fe 2+ site-occupancies at M1 and M2, obtained from the Mössbauer relative areas, suggest that Fe 2+ has a slight preference for the M1 site at temperatures below ∼500 • C, with a tendency of disordering around this temperature. At higher temperatures, Fe 2+ again prefers to occupy the M1 site, where it shows a considerable order at this site up to 750 • C. At still higher temperatures, the spectra indicated partial reduction of the Fa-component into metallic iron and the resolution of the doublets was severely deteriorated.

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“…Alternate sites of Mg1Fe1 (sphere marked as 1) and Mg2Fe2 (spheres marked as 2) are within the octahedra and Si sites within the tetrahedra, while oxygen atoms are at the corners. The high-temperature partitioning of Fe and Mg between the M1 and M2 sites occurs in synthetic olivine, and Fe segregates progressively into the M1 sites, with Mg, which increases continuously with rising temperature, preferring the M2 sites [17]. Figure 3 shows SEM photographs of MgFeSiO 4 synthesized at 1000, 900 and 800°C.…”

Section: Resultsmentioning

confidence: 99%

MgFeSiO4 prepared via a molten salt method as a new cathode material for rechargeable magnesium batteries

Nuli

Yang

et al. 2011

Chin. Sci. Bull.

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Well-crystallized MgFeSiO 4 microparticles were synthesized at different temperatures by a simple molten salt method using KCl flux. As a new cathode for rechargeable magnesium batteries, the material shows a reversible Mg 2+ intercalation-deintercalation process. In 0.25 mol/L Mg(AlCl 2 EtBu) 2 /THF electrolyte, MgFeSiO 4 synthesized at 900°C can deliver a 125.1 mAh/g initial discharge capacity and a 91.4% capacity retention on the 20th cycle at a rate of 0.1C (about 15.6 mA/g Following the development of electrolyte solutions based on Mg(AlCl 3 R) 2 and Mg(AlCl 2 RR') 2 (R, R'=alkyl or aryl groups) in tetrahydrofuran (THF) for electrochemically reversible deposition-dissolution of magnesium [1,2], rechargeable magnesium batteries have received increasing attention because of their low cost, safety, environmentally friendly nature, low electrode potential and high charge density of metallic magnesium [3]. It is said that rechargeable magnesium batteries, which are not designed to compete with lithium batteries in terms of energy density for small scale application, may eventually replace the standard batteries used in large-scale energy conversion [4,5]. However, the strong polarization of small and divalent Mg 2+ makes it difficult achieve reversible magnesium intercalation-deintercalation in many hosts [6]. So far, most effective magnesium insertion cathodes, such as transition metal sulfides or oxides, exhibit either a small discharge capacity or a low discharge voltage [7][8][9]. Therefore, it is necessary to develop new types of competitive insertion materials for the *Corresponding author (email: nlyn@sjtu.edu.cn) development of high-energy rechargeable magnesium batteries.As magnesium intercalation hosts, the materials should possess voids of suitable dimensions to uptake Mg 2+ and maintain good structural stability. Polyanionic compounds (XO 4 n− ; X=P, Si, Ge etc.) have been successfully used as the hosts of Li + insertion/extraction and as promising cathodes for lithium-ion batteries [10]. Recently, we reported the electrochemical performance of magnesium manganese silicate as a novel cathode material for rechargeable magnesium [11][12][13]. It was clearly shown that the electrode could be cycled, although the kinetic performance and cycling stability remain unsatisfactory. Orthosilicate Mg x M y SiO 4 (M=Mn, Fe, Ni, x+y=1) has a compact tetrahedral "anion" structure (SiO 4 ) 4-, which can afford intrinsic lattice stabilization through the presence of strong Si−O bonds. Furthermore, the strong inductive effect of (SiO 4 ) 4− can moderate the transition metal redox couple to generate a relatively high operating voltage. Herein, MgFeSiO 4 was prepared by a simple molten salt method, and the Mg 2+ intercalationdeintercalation process was investigated as a new cathode material for rechargeable magnesium batteries.

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Octahedral cation partitioning in Mg,Fe2+-olivine. Mossbauer spectroscopic study of synthetic (Mg0.5 Fe2+0.5)2SiO4(Fa50)

Cited by 36 publications

References 16 publications

A study of ordinary chondrites by Mössbauer spectroscopy with high‐velocity resolution

A study of ordinary chondrites by Mössbauer spectroscopy with high‐velocity resolution

High-temperature cation ordering in olivine: an in situ Mössbauer study of synthetic (Mg0.55Fe0.45)2 SiO4

MgFeSiO4 prepared via a molten salt method as a new cathode material for rechargeable magnesium batteries

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