High-pressure crystal chemistry of binary intermetallic compounds

Demchyna, R.; Leoni, Stefano; Rösner, H.; Schwarz, Ulrich

doi:10.1524/zkri.2006.221.5-7.420

Cited by 52 publications

(41 citation statements)

References 75 publications

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“…1). Thus, Si(cI16) belongs indeed to the small, but still growing set of high-pressure phases in which the reduction of point symmetry is associated with a differentiation of chemically equivalent interatomic distances [22].…”

Section: Resultsmentioning

confidence: 99%

Crystal Structure Refinement and Electronic Properties of Si(cI16)

Wosylus

Rösner

Schnelle

et al. 2009

Zeitschrift anorg allge chemie

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Abstract. Si(cI16) is prepared in polycrystalline form at 12(1.5) GPa at temperatures between 800(80) K and 1200(120) K. The crystal structure is refined by a full-profile method using x-ray powder diffraction data.Si(cI16) is diamagnetic (χ 0 = -5.6(1.8) × 10 -6 emu mol -1 ) and shows a weakly temperature-dependent electrical resistivity (ρ(300 K) = 0.3 × 10 -3 Ω m). Computations of structural and electronic properties of Si(cI16) within the local density approximation evidence the metastable character of the allotrope with respect to diamond-type silicon. The calculations yield a positional parameter which is in perfect agreement with the refined value. In agreement with the experimentally observed conductivity properties, the computed density of states evidence that the Fermi level of Si(cI16) is located in a pseudo-gap.

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Section: Resultsmentioning

confidence: 99%

Crystal Structure Refinement and Electronic Properties of Si(cI16)

Wosylus

Rösner

Schnelle

et al. 2009

Zeitschrift anorg allge chemie

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“…Ultimately, the kind of intermediate structures on the way to the CsCl-type end member will depend on the electronic structure of the particular system. 42 The theoretically predicted sequences of high-pressure structural transitions for FeSn, CoSn, and NiIn have not been observed in room-temperature DAC experiments. This discrepancy is ascribed to an energy barrier inhibiting kinetically these phase transformations.…”

Section: Discussionmentioning

confidence: 97%

High-pressure structural behavior of large-void CoSn-type intermetallics: Experiments and first-principles calculations

et al. 2008

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The high-pressure structural behavior of the binary intermetallic compounds CoSn, FeSn, and NiIn with the peculiar void containing CoSn ͑B35͒-type structure has been studied by means of room-temperature diamond anvil cell and high-temperature multianvil experiments, as well as by first-principles calculations. All three compounds remain structurally stable at pressures up to at least 25 GPa, whereas first-principles calculations predict high-pressure structural changes below 20 GPa. A plausible explanation for the discrepancy is that at room temperature, a sizable activation barrier inhibits kinetically the transformation into more close-packed polymorphs. It is supported by our experiments at temperatures around 1000°C and a pressure of 10 GPa. At these conditions, NiIn transforms into the temperature-quenchable stoichiometric CsCl-type high-pressure phase, which has been predicted in our first-principles calculations. However, CoSn and FeSn decompose into a mixture of compounds richer and poorer in tin, respectively. Nevertheless, it might be possible that lower temperatures and higher pressures may afford theoretically predicted polymorphs. In particular, a phase transformation to the FeSi-type structure predicted for CoSn is of interest as materials with the FeSi-type structure are known for unusual thermal and transport properties.

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“…Investigating the homogeneity range of the ternary substituted variety EuGa x Si 6−x (x = 0 -0.6) reveals that the phase requires a significant excess of electrons since the composition Eu[(4b)Ga − ] 2 [(4b)Si 0 ] 4 which would be in accordance with the 8 − N rule could not be realized experimentally. Since new phases comprising anionic frameworks of four-bonded atoms, like EuSi 6 [5] and EuSi 6−x Ga x [6,7] or BaSi 6−x [8,9] can be prepared by application of high pressure, we have studied phase formation in the silicon-rich part of the phase diagram of the binary system Sr-Si at elevated pressures. Here we report on high-pressure synthesis, crystal structure, chemical bonding, magnetic 0932-0776 / 06 / 1200-1485 $ 06.00 © 2006 Verlag der Zeitschrift für Naturforschung, Tübingen · http://znaturforsch.com properties, and electrical transport of the new binary compound SrSi 6 .…”

Section: Introductionmentioning

confidence: 99%

High-pressure Synthesis of Strontium Hexasilicide

Wosylus

Prots

Burkhardt

et al. 2006

Zeitschrift Für Naturforschung B

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The binary phase SrSi 6 was prepared at a pressure of 10(1) GPa and a temperature of 1520(150) K. Single crystal refinements and powder diffraction data reveal that the compound crystallizes in the orthorhombic crystal system (Cmcm, a = 4.4692(4), b = 10.256(1), c = 11.698(1)Å) and is isopointal to EuGa 2 Ge 4 and EuSi 6 . Exothermic decomposition of the compound into SrSi 2 and Si at 797 K and ambient pressure indicates that the compound is a metastable high-pressure phase. Analysis of the chemical bonding using the electron localization function and calculated charge densities reveals covalent bonding within the polyanion of four-bonded silicon atoms. Strontium cations are enclosed in the 3D net resulting in an electron balance Sr 2+ [Si 0 ] 2− 6 . In the electronic density of states the excess electrons of the framework are assigned to a filling of antibonding bands. SrSi 6 is a metallic conductor with an electrical resistivity of ρ ≈ 250 µΩ·cm at 300 K. Magnetization measurements indicate diamagnetic behaviour (χ 0 = −50 · 10 −6 emu·mol −1 ).

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High-pressure crystal chemistry of binary intermetallic compounds

Cited by 52 publications

References 75 publications

Crystal Structure Refinement and Electronic Properties of Si(cI16)

Crystal Structure Refinement and Electronic Properties of Si(cI16)

High-pressure structural behavior of large-void CoSn-type intermetallics: Experiments and first-principles calculations

High-pressure Synthesis of Strontium Hexasilicide

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