X-ray studies on alloys

Westgren, Arne; Phragmén, Gösta

doi:10.1039/tf9292500379

Cited by 50 publications

(26 citation statements)

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“…A recent example is the understanding of the in situ stability of Pd-Ga intermetallic compounds, which are highly selective hydrogenation catalysts. [14,15] The intermetallic compounds MnSn 2 , FeSn 2 and CoSn 2 cannot be classified within the known bonding concepts after Zintl-Klemm, [16][17][18][19][20][21] Hume-Rothery [22][23][24][25][26] or Laves, [27][28][29] so the prediction of atomic interactions in these compounds is not straightforward. All three TSn 2 (T = Mn, Fe, Co) compounds crystallise in the CuAl 2 type of crystal structure (space group I4/mcm, T in 4a, Sn in 8h) and the crystal structures have been recently reinvestigated.…”

Section: Introductionmentioning

confidence: 99%

Chemical Bonding in Compounds of the CuAl₂ Family: MnSn₂, FeSn₂ and CoSn₂

Armbrüster

Schnelle

Cardoso‐Gil

et al. 2010

Chemistry A European J

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A model for the chemical bonding in the isostructural intermetallic compounds MnSn(2), FeSn(2) and CoSn(2), crystallising in the CuAl(2)-type structure, is developed. The description is based on quantum-chemical calculations applying the electron localisability approach as well as on experimental results obtained from Raman spectroscopy, Hall effect and electrical resistivity measurements on oriented single crystals. The analysis of the chemical bonding reveals four different covalent interactions leading to the formation of interpenetrating 6(3) nets of tin and chains of transition-metal atoms T (T=Mn, Fe or Co) along [001], which are interconnected by three-centre bonds. Polarised Raman measurements on oriented single crystals allowed the determination of the bond strengths, resulting in a bond order of 0.5 within the 6(3) nets, while the three-centre interactions show bond orders of up to 1. Measurements show a metal-like temperature dependence of the resistivity. A comparison of the results with the bonding models obtained for the isostructural compounds CuAl(2), TiSb(2) and VSb(2) reveals the influence of the main-group element on the connectivity pattern.

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Section: Introductionmentioning

confidence: 99%

Chemical Bonding in Compounds of the CuAl₂ Family: MnSn₂, FeSn₂ and CoSn₂

Armbrüster

Schnelle

Cardoso‐Gil

et al. 2010

Chemistry A European J

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“…12) The electronic properties of Co 3 Mo 3 C have not been reported yet, although Co 3 Mo 3 C has been known to exist since 1928. 13) In this letter, we report the magnetic properties of Co 3 Mo 3 N and Co 3 Mo 3 C, particularly for the carbide for the first time. In both systems, no magnetic long-range order was confirmed by 59 Co nuclear magnetic resonance (NMR) studies.…”

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confidence: 97%

Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co₃Mo₃C

et al. 2010

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We report the magnetic properties of the cobalt molybdenum -carbide-type compounds Co 3 Mo 3 C and Co 3 Mo 3 N. The magnetic susceptibility of Co 3 Mo 3 C shows a Curie-Weiss temperature dependence at high temperatures and a broad maximum at around 100 K, whereas that of Co 3 Mo 3 N shows a nearly temperature-independent enhanced Pauli paramagnetic behavior. The absence of a magnetic long-range order was confirmed by the nuclear magnetic resonance technique in both the compounds. As expected from the broad maximum of , we observed an itinerant electron metamagnetic transition at around 37 T in Co 3 Mo 3 C.Ternary transition-metal interstitial compounds M 3 M 0 3 X (M: 3d transition metal, M 0 : 4d, 5d transition metal of early groups) are known to have the -carbide-type structure with the cubic space group Fd " 3 3m (227). Because of their hardness and catalytic ability, -carbide-type compounds have been studied for about half a century from a technological viewpoint. However, their electronic properties were less studied. In the structure, M, M 0 , and X atoms occupy the Wyckoff positions 16d/32e, 48f, and 16c, respectively. Focusing on M, which is expected to contribute mainly to the magnetic properties of the system, the 16d/32e sites form a three-dimensional (3D) network of the stella quadrangula (SQ) lattice. 1) SQ is a polyhedron as each face of a tetrahedron composed of 32e atoms is capped with another tetrahedron whose extra apex is a 16d atom. Because the SQ lattice is composed of tetrahedrons, magnetic properties are interesting from the aspect of geometrical frustration. Recently, we have reported a non-Fermi-liquid behavior in pure Fe 3 Mo 3 N without any tuning of pressure or concentration. 2) The magnetic properties of isostructural compounds are also expected to be of a wide variety.The synthetic routes of cobalt molybdenum -carbidetype compounds Co 3 Mo 3 X (X ¼ C, N) have been studied well. Co 3 Mo 3 N was first synthesized by Houmes et al. by ammonolysis of oxide precursors. 3) Following them, several methods of the reduction and nitridation of oxide precursors such as the plasma method 4) and urea method 5) have been reported. The resistivity shows a metallic behavior 5,6) and the magnetic susceptibility is of a Pauli paramagnet. 4,7) A superparamagnetic behavior and the absence of a magnetic long-range order were also suggested. 7) Although Co 3 Mo 3 C was first made by arc melting of elements, more moderate methods have been developed to avoid the excess occupation of Mo atoms of the 16d site. 8,9) Typical methods are reduction by H 2 and successive CO/CO 2 buffered gas treatment with cobalt tris(ethylenediamine) molybdate, 10)

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“…The TijNi, the filled TijNi, and the related T) carbide type structures have been known for some time [68]. Much of the earlier work revealed the variety of combinations of metals which adopt this framework to make it the most frequently found structure of binary intermetallics of stoichiometry AjB [69].…”

Section: Resultsmentioning

confidence: 99%

Interstitially stabilized phases in the zirconium-nickel system

Mackay

1993

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X-ray studies on alloys

Cited by 50 publications

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Chemical Bonding in Compounds of the CuAl₂ Family: MnSn₂, FeSn₂ and CoSn₂

Chemical Bonding in Compounds of the CuAl₂ Family: MnSn₂, FeSn₂ and CoSn₂

Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co₃Mo₃C

Interstitially stabilized phases in the zirconium-nickel system

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X-ray studies on alloys

Cited by 50 publications

References 0 publications

Chemical Bonding in Compounds of the CuAl2 Family: MnSn2, FeSn2 and CoSn2

Chemical Bonding in Compounds of the CuAl2 Family: MnSn2, FeSn2 and CoSn2

Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co3Mo3C

Interstitially stabilized phases in the zirconium-nickel system

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Chemical Bonding in Compounds of the CuAl₂ Family: MnSn₂, FeSn₂ and CoSn₂

Chemical Bonding in Compounds of the CuAl₂ Family: MnSn₂, FeSn₂ and CoSn₂

Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co₃Mo₃C