Sur l'absence d'ordre magnetique dans la forme quadratique de FeS

Bertaut, E.F.; Burlet, P.; Chappert, J.

doi:10.1016/0038-1098(65)90090-6

Cited by 84 publications

(60 citation statements)

References 6 publications

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“…X-ray diffraction patterns from natural mackinawite (Kuovo et al, 1963), and neutron (Bertaut et al, 1965) and electron (Uda, 1968) diffraction analyses of synthetic mackinawite, support this interpretation.…”

Section: Introductionsupporting

confidence: 61%

Synthesis and Rietveld crystal structure refinement of mackinawite, tetragonal FeS

et al. 1995

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Mackinawite, tetragonal FeS, has been synthesised by reacting iron with Na2S solutions. A Rietveld structure refinement of X-ray powder diffraction data, recorded using X-rays monochromated from synchrotron radiation with a wavelength of 0.6023 A, has been performed. The structure has been refined in the tetragonal s~ace group, P4/nmm, and has the following cell parameters: a = 3.6735(4), c = 5.0328(7) A, V = 67.914 (24) A 3. Our refinement shows that the FeS4 tetrahedron in mackinawite is almost perfectly regular, with a much smaller distortion than has been previously reported. An improved X-ray diffraction data set is provided.I~Ywo~s: mackinawite, Rietveld structure refinement, synthesis.

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Section: Introductionsupporting

confidence: 61%

Synthesis and Rietveld crystal structure refinement of mackinawite, tetragonal FeS

et al. 1995

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“…[49][50][51] Moreover, both room temperature neutron diffraction 52 and Mössbauer data 53 at 4.2 K with an external field testify to the absence of an iron magnetic moment in mackinawite. In earlier studies, we have demonstrated that the inclusion of dispersion corrections yields improved agreement between the predicted lattice parameters (a = 3.587 Å, c = 4.908 Å, and c/a = 1.368) 33,34 and those measured experimentally.…”

Section: Computational Detailsmentioning

confidence: 91%

Activation and dissociation of CO2 on the (001), (011), and (111) surfaces of mackinawite (FeS): A dispersion-corrected DFT study

Dzade

Roldan

Leeuw

2015

The Journal of Chemical Physics

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Iron sulfide minerals, including mackinawite (FeS), are relevant in origin of life theories, due to their potential catalytic activity towards the reduction and conversion of carbon dioxide (CO 2 ) to organic molecules, which may be applicable to the production of liquid fuels and commodity chemicals. However, the fundamental understanding of CO 2 adsorption, activation, and dissociation on FeS surfaces remains incomplete. Here, we have used density functional theory calculations, corrected for long-range dispersion interactions (DFT-D2), to explore various adsorption sites and configurations for CO 2 on the low-index mackinawite (001), (110), and (111) surfaces. We found that the CO 2 molecule physisorbs weakly on the energetically most stable (001) surface but adsorbs relatively strongly on the (011) and (111) FeS surfaces, preferentially at Fe sites. The adsorption of the CO 2 on the (011) and (111) surfaces is shown to be characterized by significant charge transfer from surface Fe species to the CO 2 molecule, which causes a large structural transformation in the molecule (i.e., forming a negatively charged bent CO 2 −δ species, with weaker C-O confirmed via vibrational frequency analyses). We have also analyzed the pathways for CO 2 reduction to CO and O on the mackinawite (011) and (111) surfaces. CO 2 dissociation is calculated to be slightly endothermic relative to the associatively adsorbed states, with relatively large activation energy barriers of 1.25 eV and 0.72 eV on the (011) and (111)

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“…1a) in the non-magnetic state, reflecting the fact that both room temperature neutron diffraction 59 and Mössbauer data 60 at 4.2 K with an external field testify the absence of an iron magnetic moment in mackinawite. This effect has been attributed to strong covalency in the Fe-S bonding, 59 on the one hand and to extensive d-electron delocalisation within the sheets, 60 on the other hand. An earlier DFT structural optimization of FeS performed by Devey et al also predicted the stable ground state to be nonmagnetic.…”

Section: Methodsmentioning

confidence: 98%

The surface chemistry of NO_x on mackinawite (FeS) surfaces: a DFT-D2 study

Dzade

Roldan

Leeuw

2014

Phys. Chem. Chem. Phys.

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We present density functional theory calculations with a correction for the long-range interactions (DFT-D2) of the bulk and surfaces of mackinawite (FeS), and subsequent adsorption and dissociation of NO x gases (nitrogen monoxide (NO) and nitrogen dioxide (NO 2 )). Our results show that these environmentally important molecules interact very weakly with the energetically most stable (001) surface, but adsorb relatively strongly onto the FeS (011), (100) and (111) surfaces, preferentially at Fe sites via charge donation from these surface species. The NO x species exhibit a variety of adsorption geometries, with the most favourable for NO being the monodentate Fe-NO configuration, whereas NO 2 is calculated to form a bidentate Fe-NOO-Fe configuration. From our calculated thermochemical energy and activation energy barriers for the direct dissociation of NO and NO 2 on the FeS surfaces, we show that NO prefers molecular adsorption, while dissociative adsorption, i.e. NO 2 (ads) -[NO(ads) + O(ads)] is preferred over molecular adsorption for NO 2 onto the mackinawite surfaces. However, the calculated high activation barriers for the further dissociation of the second N-O bond to produce either [N(ads) and 2O(ads)] or [N(ads) and O 2 (ads)] suggest that complete dissociation of NO 2 is unlikely to occur on the mackinawite surfaces.

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Sur l'absence d'ordre magnetique dans la forme quadratique de FeS

Cited by 84 publications

References 6 publications

Synthesis and Rietveld crystal structure refinement of mackinawite, tetragonal FeS

Synthesis and Rietveld crystal structure refinement of mackinawite, tetragonal FeS

Activation and dissociation of CO2 on the (001), (011), and (111) surfaces of mackinawite (FeS): A dispersion-corrected DFT study

The surface chemistry of NO_x on mackinawite (FeS) surfaces: a DFT-D2 study

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Sur l'absence d'ordre magnetique dans la forme quadratique de FeS

Cited by 84 publications

References 6 publications

Synthesis and Rietveld crystal structure refinement of mackinawite, tetragonal FeS

Synthesis and Rietveld crystal structure refinement of mackinawite, tetragonal FeS

Activation and dissociation of CO2 on the (001), (011), and (111) surfaces of mackinawite (FeS): A dispersion-corrected DFT study

The surface chemistry of NOx on mackinawite (FeS) surfaces: a DFT-D2 study

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The surface chemistry of NO_x on mackinawite (FeS) surfaces: a DFT-D2 study