Synthesis and crystal structure of cubic V11Cu9Ga46 – A 512-fold super structure of a simple bcc packing

Lux, Rainer; Kuntze, Verena; Hillebrecht, Harald

doi:10.1016/j.solidstatesciences.2012.07.028

Cited by 12 publications

(5 citation statements)

References 16 publications

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“…These structural variants are discussed in reference27. V 11 Cu 9 Ga 46 52 is probably the most complex bcc superstructure with ordering and vacancy formation. Further variants are summarized by Sluiter53 in a general work on bcc , fcc , and hcp superstructures.…”

Section: Ordering Variants Of the Bcc Typementioning

confidence: 99%

Coloring, Distortions, and Puckering in Selected Intermetallic Structures from the Perspective of Group‐Subgroup Relations

Pöttgen

2014

Zeitschrift anorg allge chemie

116

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Group‐subgroup relations are a compact and concise tool for structure systemization. The present review summarizes the use of Bärnighausen trees for classification of intermetallic structures into structural families. The overview starts with group‐subgroup relationships between the structures of the metallic elements (W, In, α‐Po, β‐Po, Pa, α‐Sn, β‐Sn) followed by examples for ordered close‐packed arrangements that derive from fcc, hcp, and bcc subcells (e.g. CuAu, Cu3Au, MoNi4, ZrAl3, FeAl, MoSi2). The main focus lies on more complex structures that derive from aristotypes with comparatively high space group symmetry: AlB2, Fe2P, U3Si2, BaAl4, La3Al11, NaZn13, CaCu5, and Re3B. The symmetry reductions arise from coloring of sites with different atoms or from distortions / puckering due to size restrictions (different radii of atoms). The resulting superstructures are discussed along with the consequences for diffraction experiments, chemical bonding, and physical properties.

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Section: Ordering Variants Of the Bcc Typementioning

confidence: 99%

Coloring, Distortions, and Puckering in Selected Intermetallic Structures from the Perspective of Group‐Subgroup Relations

Pöttgen

2014

Zeitschrift anorg allge chemie

116

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“…Small variations of the composition of this phase have been found to lead to variations on this host–guest theme. In Mo 6 Ga 31 and Mo 8 Ga 40.88 S 0.86 , dimers and columns of such guest clusters were observed embedded in a similar host matrix, and more extensive structural chemistry was revealed in the structure of V 11 Cu 9 Ga 46 by Lux et al Based on these observations, we were interested in how the addition of Cu to the Mo–Ga system could influence these host–guest type arrangements. In the structure of Mo 2 Cu 0.9 Ga 5.1 , the answer appears to be the suppression of structural complexity in favor of more simple atomic packing.…”

Section: Introductionmentioning

confidence: 97%

Defusing Complexity in Intermetallics: How Covalently Shared Electron Pairs Stabilize the FCC Variant Mo₂Cu_xGa_6–x(x≈ 0.9)

2015

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Simple sphere packings of metallic atoms are generally assumed to exhibit highly delocalized bonding, often visualized in terms of a lattice of metal cations immersed in an electron gas. In this Article, we present a compound that demonstrates how covalently shared electron pairs can, in fact, play a key role in the stability of such structures: Mo2Cu(x)Ga(6-x) (x ≈ 0.9). Mo2Cu(x)Ga(6-x) adopts a variant of the common TiAl3 structure type, which itself is a binary coloring of the fcc lattice. Electronic structure calculations trace the formation of this compound to a magic electron count of 14 electrons/T atom (T = transition metal) for the TiAl3 type, for which the Fermi energy coincides with an electronic pseudogap. This count is one electron/T atom lower than the electron concentration for a hypothetical MoGa3 phase, making this structure less competitive relative to more complex alternatives. The favorable 14 electron count can be reached, however, through the partial substitution of Ga with Cu. Using DFT-calibrated Hückel calculations and the reversed approximation Molecular Orbital (raMO) method, we show that the favorability of the 14 electron count has a simple structural origin in terms of the 18 - n rule of T-E intermetallics (E = main group element): the T atoms of the TiAl3 type are arranged into square nets whose edges are bridged by E atoms. The presence of shared electron pairs along these T-T contacts allows for 18 electron configurations to be achieved on the T atoms despite possessing only 18 - 4 = 14 electrons/T atom. This bonding scheme provides a rationale for the observed stability range of TiAl3 type TE3 phases of ca. 13-14 electrons/T atom, and demonstrates how the concept of the covalent bond can extend even to the most metallic of structure types.

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“…Ternary compounds V 2 Cu 3 Ga 8 , Mo 2 Cu 3 Ga 8 , and W 2 Cu 3 Ga 8 with the crystal structures reminiscent of the PtHg 4 structure type are formed . Moreover, the superstructure compounds V 11 Cu 9 Ga 46 and Ta 7 Cu 10 Ga 34 were obtained. Recent results show that the Ga/Cu combination can also be applied to a rare-earth metal Yb yielding complex ternary intermetallics Yb 6 (CuGa) 50 and Yb 6 (CuGa) 51 .…”

Section: Discussionmentioning

confidence: 96%

Crystal Growth of Intermetallics from the Joint Flux: Exploratory Synthesis through the Control of Valence Electron Count

et al. 2019

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In this study, we modify the flux-growth method for the purpose of exploratory synthesis of ternary intermetallic compounds. Our concept is based on the assumption that valence electron count plays a crucial role in the stability of polar intermetallic compounds of different structure types. Control of the valence electron count parameter is made possible through the use of an excess of two metals having a different number of valence electrons. By gradually changing the ratio between these metals in the joint flux, we scan the gross number of valence electrons and explore the crystallization of new compounds. In the ternary system Re−Ga−Zn, we detect compounds belonging to three structure types, ReGa 5 , PtHg 4 , and V 8 Ga 41 , while gradually increasing the content of Zn metal in the flux. Two new compounds, ReGa 3 Zn and Re 8 Ga 41−x Zn x with x = 21.2(5), are obtained in the form of high-quality single crystals, and the former compound shows the narrow-gap semiconducting behavior favorable for high thermoelectric performance.

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Synthesis and crystal structure of cubic V11Cu9Ga46 – A 512-fold super structure of a simple bcc packing

Cited by 12 publications

References 16 publications

Coloring, Distortions, and Puckering in Selected Intermetallic Structures from the Perspective of Group‐Subgroup Relations

Coloring, Distortions, and Puckering in Selected Intermetallic Structures from the Perspective of Group‐Subgroup Relations

Defusing Complexity in Intermetallics: How Covalently Shared Electron Pairs Stabilize the FCC Variant Mo₂Cu_xGa_6–x(x≈ 0.9)

Crystal Growth of Intermetallics from the Joint Flux: Exploratory Synthesis through the Control of Valence Electron Count

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Synthesis and crystal structure of cubic V11Cu9Ga46 – A 512-fold super structure of a simple bcc packing

Cited by 12 publications

References 16 publications

Coloring, Distortions, and Puckering in Selected Intermetallic Structures from the Perspective of Group‐Subgroup Relations

Coloring, Distortions, and Puckering in Selected Intermetallic Structures from the Perspective of Group‐Subgroup Relations

Defusing Complexity in Intermetallics: How Covalently Shared Electron Pairs Stabilize the FCC Variant Mo2CuxGa6–x(x≈ 0.9)

Crystal Growth of Intermetallics from the Joint Flux: Exploratory Synthesis through the Control of Valence Electron Count

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Defusing Complexity in Intermetallics: How Covalently Shared Electron Pairs Stabilize the FCC Variant Mo₂Cu_xGa_6–x(x≈ 0.9)