The new chimney-ladder phases Co2Si3 and Re4Ge7 formed by treatment at high temperatures and pressures

Larchev, V. I.; Попова, С. В.

doi:10.1016/0022-5088(82)90131-x

Cited by 20 publications

(11 citation statements)

References 5 publications

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“…Similar examples of compounds beyond the range of stability (in terms of VEC), which are formed under extreme (high-pressure) conditions, can be found in the family of Nowotny chimney-ladders. Specifically, the 15e – -Co 2 Si 3 and 13.67e – -Mn 3 Ge 5 are examples of high-pressure phases. , …”

Section: Resultsmentioning

confidence: 99%

Electron-Precise Semiconducting ReGa₂Ge: Extending the IrIn₃ Structure Type to Group 7 of the Periodic Table

et al. 2020

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Intermetallic compounds with semiconducting properties are rare, but they give rise to advanced materials for energy conversion and saving applications. Here, we present ReGa2Ge, a new electron-precise narrow-gap intermetallic semiconductor. The compound crystallizes in the IrIn3 structure type (space group P42/mnm, a = 6.5734(3) Å, c = 6.7450(8) Å, and Z = 4), where Re atoms occupy the Ir site, while Ga and Ge jointly populate the In sites. 69,71Ga nuclear quadrupole resonance spectroscopy indicates nonstatistical partially ordered distribution of Ga and Ge over two available crystallographic sites; however, the Ga:Ge ratio is exactly 2:1 without noticeable homogeneity range. The stoichiometry of ReGa2Ge ensures its precise valence electron count, which is 17 e– per formula unit. Accordingly, a narrow energy gap opens up at the Fermi energy in the electronic structure. Electrical resistivity, Seebeck coefficient, and thermal conductivity are in agreement with the semiconducting behavior deduced from the electronic structure calculations and point to prospective thermoelectric properties at high temperatures. Bonding analysis reveals dominant covalency in Re–E (E = Ga, Ge) and Re–Re interactions.

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Section: Resultsmentioning

confidence: 99%

Electron-Precise Semiconducting ReGa₂Ge: Extending the IrIn₃ Structure Type to Group 7 of the Periodic Table

et al. 2020

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“…One more important feature of the NCL phases is the valence electron count (VEC), which varies within the range of 12 to 14 per transition element atom, with possible minor deviations to slightly higher values, such as for Rh 17 Ge 22 (VEC = 14.18) [23]. Noteworthy is a unique case of hp-Co 2 Si 3 (VEC = 15); however, this compound can be prepared only at a high pressure of 7 GPa [24]. Based on the crystal and electronic structures of NCL phases, the 14-electron rule has been formulated [9,15,16], which was later transformed into the 18-n rule [25,26].…”

Section: Introductionmentioning

confidence: 99%

Nowotny Chimney Ladder Phases with Group 5 Metals: Crystal and Electronic Structure and Relations to the CrSi2 Structure Type

et al. 2020

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Nowotny chimney ladder (NCL) phases are intermetallic compounds formed by transition metals and metals of groups 13 and 14. This family can be expanded by combining two p-elements from different groups with those transition metals, for which the corresponding binary NCL phases are unknown. In this paper, we present three new compounds in the V-Al-Ge, Nb-Al-Ge, and Nb-Ga-Ge systems related to the TiSi2 structure type (Sp. Gr. Fddd) obtained with the standard ampule technique. The crystal structures of the new compounds were determined using synchrotron powder X-ray diffraction data. A transition to the CrSi2 structure type was detected upon changing the composition from VAl0.72(2)Ge1.28(2) to VAl1.534(3)Ge0.466(3). According to the 18–n rule, all the compounds are metallic conductors, which was supported by the electronic structure calculations. It was shown that the expected energy gap located above the Fermi level in the vanadium-based NCL compound collapsed into a pseudogap upon the replacement of V by Nb.

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“…Nowotny chimney-ladder phases represent a large family of T-E intermetallic compounds (Ttransition metal, Emain group element) with a general formula of T n E m (1 < m/n ≤ 2). [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Their crystal structures present an interesting case of composite structures, with p-element atoms forming a nested n-fold spiral ("ladder") inside a β-Sn-type spiral of d-element atoms ("chimney"). [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] The transition metal spiral has a short period c T of 4-6 Å and remains virtually identical between various phases, while the period of a full rotation for the main group element helix varies significantly and can sometimes reach hundreds of ångströms leading to an incommensurate structure.…”

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Itinerant ferromagnet Re_4−xMn_xGe_7−δ (x = 0.9–1.5, δ = 0.42–0.44) with incommensurate chimney-ladder structure stabilised at ambient pressure

Khalaniya¹,

Verchenko²,

Bogach³

et al. 2023

Dalton Trans.

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The new chimney-ladder phases Co2Si3 and Re4Ge7 formed by treatment at high temperatures and pressures

Cited by 20 publications

References 5 publications

Electron-Precise Semiconducting ReGa₂Ge: Extending the IrIn₃ Structure Type to Group 7 of the Periodic Table

Electron-Precise Semiconducting ReGa₂Ge: Extending the IrIn₃ Structure Type to Group 7 of the Periodic Table

Nowotny Chimney Ladder Phases with Group 5 Metals: Crystal and Electronic Structure and Relations to the CrSi2 Structure Type

Itinerant ferromagnet Re_4−xMn_xGe_7−δ (x = 0.9–1.5, δ = 0.42–0.44) with incommensurate chimney-ladder structure stabilised at ambient pressure

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The new chimney-ladder phases Co2Si3 and Re4Ge7 formed by treatment at high temperatures and pressures

Cited by 20 publications

References 5 publications

Electron-Precise Semiconducting ReGa2Ge: Extending the IrIn3 Structure Type to Group 7 of the Periodic Table

Electron-Precise Semiconducting ReGa2Ge: Extending the IrIn3 Structure Type to Group 7 of the Periodic Table

Nowotny Chimney Ladder Phases with Group 5 Metals: Crystal and Electronic Structure and Relations to the CrSi2 Structure Type

Itinerant ferromagnet Re4−xMnxGe7−δ (x = 0.9–1.5, δ = 0.42–0.44) with incommensurate chimney-ladder structure stabilised at ambient pressure

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Electron-Precise Semiconducting ReGa₂Ge: Extending the IrIn₃ Structure Type to Group 7 of the Periodic Table

Electron-Precise Semiconducting ReGa₂Ge: Extending the IrIn₃ Structure Type to Group 7 of the Periodic Table

Itinerant ferromagnet Re_4−xMn_xGe_7−δ (x = 0.9–1.5, δ = 0.42–0.44) with incommensurate chimney-ladder structure stabilised at ambient pressure