The structures of the η-carbides Ni6Mo6C, Co6Mo6C, and Co6Mo6C2

Newsam, J. M.; Jacobson, Allan J.; McCandlish, L. E.; Polizzotti, R. S.

doi:10.1016/0022-4596(88)90170-3

Cited by 53 publications

(31 citation statements)

References 12 publications

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“…The crystal structures of Fe 6 W 6 C and Fe 3 W 3 C were derived from neutron diffraction data [12,13] confirming the localisation of carbon on site 8a and 16c, respectively. Later on [11] Rietveld refinement of neutron powder data confirmed the crystal structures of the Z-12-carbides Ni 6 Mo 6 C and Co 6 Mo 6 C (C on site 8a), and the Z-6-carbide Co 3 Mo 3 C (C on site 16c).…”

Section: Introductionsupporting

confidence: 54%

“…2). As pointed out in previous work [11,21] the metal atom positions can be derived from the Ti 2 Ni-structure. Carbon is located in octahedral voids formed exclusively by Ta-atoms.…”

Section: Resultsmentioning

confidence: 99%

“…Ta 3 Al 2 C, P4 1 [10]. Another classification refers to the order of metals (Z 1 -carbide: W 3 Co 3 C; Z 2 -carbide: W 4 Co 2 C [3]) and the carbon content (Z-6-carbide: M 3 M 0 3 C, C on site 16c; Z-12-carbide: M 6 M 0 6 C, C on site 8a [11]). The crystal structures of Fe 6 W 6 C and Fe 3 W 3 C were derived from neutron diffraction data [12,13] confirming the localisation of carbon on site 8a and 16c, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, crystal growth, and structure of Ta3Al2CoC—An ordered quarternary cubic η-carbide and the first single crystal study of a η-carbide

Etzkorn

Hillebrecht

2008

Journal of Solid State Chemistry

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Section: Introductionsupporting

confidence: 54%

“…2). As pointed out in previous work [11,21] the metal atom positions can be derived from the Ti 2 Ni-structure. Carbon is located in octahedral voids formed exclusively by Ta-atoms.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis, crystal growth, and structure of Ta3Al2CoC—An ordered quarternary cubic η-carbide and the first single crystal study of a η-carbide

Etzkorn

Hillebrecht

2008

Journal of Solid State Chemistry

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“…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) topotactic carburization of Co 3 Mo 3 N by temperature-programmed reduction (TPR), 11) and one-step thermal decomposition of a mixed-salt precursor. 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.…”

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confidence: 99%

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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“…In contrast, the 8a site of W 3 Co 3 C is empty but the 16c site is fully occupied by carbon. 19 In a nitrogen atmosphere, pure W 3 Co 3 C phase cannot be obtained from the pyrolysis of the precursor. In addition to the amorphous carbon, a mixture of W 3 Co 3 C and W 6 Co 6 C can be obtained via the pyrolysis of the precursor, the W 6 Co 6 C phase, or the W 3 Co 3 C phase at 900°C in a nitrogen atmosphere.…”

Section: June 1999mentioning

confidence: 99%

Preparation of Tungsten Cobalt Carbides and Oxide via an Organometallic Heterobimetallic Complex as a Single‐Source Precursor

Shyu

Sung

et al. 1999

Journal of the American Ceramic Society

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Tungsten cobalt carbides and oxides can be obtained via a single-step pyrolysis of an organometallic single-source precursor ( 5 -C 5 H 5 )(CO) 3 WCo(CO) 4 (1). Pyrolysis of 1 in an oxygen atmosphere produced WCoO 4 at 600°C. In a nitrogen atmosphere W 6 Co 6 C was obtained when 1 was heated at 700°C. However, under vacuum, the pyrolysis of 1 produced the other phase-W 3 Co 3 C-at 700°C. Both carbides were contaminated with graphitic carbon, as indicated by their ESCA spectra. Powders that were obtained by using these procedures had particle sizes of up to 100 µm. Micrography showed that the particles were porous, which indicated outgassing during pyrolysis.

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The structures of the η-carbides Ni6Mo6C, Co6Mo6C, and Co6Mo6C2

Cited by 53 publications

References 12 publications

Synthesis, crystal growth, and structure of Ta3Al2CoC—An ordered quarternary cubic η-carbide and the first single crystal study of a η-carbide

Synthesis, crystal growth, and structure of Ta3Al2CoC—An ordered quarternary cubic η-carbide and the first single crystal study of a η-carbide

Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co₃Mo₃C

Preparation of Tungsten Cobalt Carbides and Oxide via an Organometallic Heterobimetallic Complex as a Single‐Source Precursor

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The structures of the η-carbides Ni6Mo6C, Co6Mo6C, and Co6Mo6C2

Cited by 53 publications

References 12 publications

Synthesis, crystal growth, and structure of Ta3Al2CoC—An ordered quarternary cubic η-carbide and the first single crystal study of a η-carbide

Synthesis, crystal growth, and structure of Ta3Al2CoC—An ordered quarternary cubic η-carbide and the first single crystal study of a η-carbide

Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co3Mo3C

Preparation of Tungsten Cobalt Carbides and Oxide via an Organometallic Heterobimetallic Complex as a Single‐Source Precursor

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Itinerant Electron Metamagnetism in η-Carbide-Type Compound Co₃Mo₃C