High-Pressure Synthesis and Chemical Bonding of Barium Trisilicide BaSi3

Hübner, Julia‐Maria; Akselrud, Lev; Schnelle, Walter; Burkhardt, Ulrich; Bobnar, Matej; Prots, Yurii; Grin, Yuri; Schwarz, Ulrich

doi:10.3390/ma12010145

Cited by 9 publications

(4 citation statements)

References 52 publications

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“…Ca and Sr charges are similar and higher in value than the Ba charge. 49 − 51 The charge of the hydrogen anion, , decreases in compression (in absolute numbers—toward neutral charge) regardless of the structure. Within the I 4/ mmm tetrahydrides, the charge is highest (the most negatively charged) in Sr and then decreases for Ca and furthermore for Ba, while BaH 4 is smaller than its tetragonal analogue.…”

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confidence: 99%

Chemically Assisted Precompression of Hydrogen Molecules in Alkaline-Earth Tetrahydrides

Peña-Álvarez

Binns

Marqués

et al. 2022

J. Phys. Chem. Lett.

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Through a series of high pressure diamond anvil experiments, we report the synthesis of alkaline earth (Ca, Sr, Ba) tetrahydrides, and investigate their properties through Raman spectroscopy, X-ray diffraction, and density functional theory calculations. The tetrahydrides incorporate both atomic and quasi-molecular hydrogen, and we find that the frequency of the intramolecular stretching mode of the units downshifts from Ca to Sr and to Ba upon compression. The experimental results indicate that the larger the host cation, the longer the bond. Analysis of the electron localization function (ELF) demonstrates that the lengthening of the H–H bond is caused by the charge transfer from the metal to and by the steric effect of the metal host on the H–H bond. This effect is most prominent for BaH 4 , where the precompression of units at 50 GPa results in bond lengths comparable to that of pure H 2 above 275 GPa.

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confidence: 99%

Chemically Assisted Precompression of Hydrogen Molecules in Alkaline-Earth Tetrahydrides

Peña-Álvarez

Binns

Marqués

et al. 2022

J. Phys. Chem. Lett.

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“…Additional information can be extracted from the shape of QTAIM atoms. In fact, La is rather spherical, which is typical for cations in similar compounds, 9 , 45 − 47 and both Ge and Pd basins possess a polyhedral shape. What is more, not only the shared faces between Ge2 and Ge3 are flat, which is characteristic for homopolar bonds, but also those between Ge and Pd.…”

Section: Resultsmentioning

confidence: 99%

La₂Pd₃Ge₅ and Nd₂Pd₃Ge₅ Compounds: Chemical Bonding and Physical Properties

et al. 2021

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The two La 2 Pd 3 Ge 5 and Nd 2 Pd 3 Ge 5 compounds, crystallizing in the oI 40-U 2 Co 3 Ge 5 crystal structure, were targeted for analysis of their chemical bonding and physical properties. The compounds of interest were obtained by arc melting and characterized by differential thermal analysis, scanning electron microscopy, and X-ray diffraction both on powder and on a single crystal (for the La analogue), to ensure the high quality of the samples and accurate crystallographic data. Chemical bonding was studied by analyzing the electronic structure and effective QTAIM charges of La 2 Pd 3 Ge 5 . A significant charge transfer mainly occurs from La to Pd so that Ge species assume tiny negative charges. This result, together with the -(I)COHP analysis, suggests that, in addition to the expected homopolar Ge bonds within zigzag chains, heteropolar interactions between Ge and the surrounding La and Pd occur with multicenter character. Covalent La–Pd interactions increase the complexity of chemical bonding, which could not be adequately described by the simplified, formally obeyed, Zintl–Klemm scheme. Electric resistivity, specific heat, magnetization, and magnetic susceptibility as a function of temperature indicate for both compounds a metallic-like behavior. For Nd 2 Pd 3 Ge 5 , two low-temperature phase transitions are detected, leading to an antiferromagnetic ground state.

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“…The obtained flaky CI/SiBaFe particles exhibited a small average diameter, which reduced the possibility for the formation of a conductive network among particles. On the other hand, low conductivity of the doped Si and Ba led to the weakened electron transport capacity of flaky CI/SiBaFe-15 particles [44][45][46]. Consequently, the ε ′ and ε ′′ of CI/SiBaFe-15 were significantly lower than that of CI at room temperature.…”

Section: Resultsmentioning

confidence: 99%

Enhanced Thermal Stability of Carbonyl Iron Nanocrystalline Microwave Absorbents by Pinning Grain Boundaries with SiBaFe Alloy Nanoparticles

Xu,

Chen,

et al. 2024

Nanomaterials

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Nanocrystalline carbonyl iron (CI) particles are promising microwave absorbents at elevated temperature, whereas their excessive grain boundary energy leads to the growth of nanograins and a deterioration in permeability. In this work, we report a strategy to enhance the thermal stability of the grains and microwave absorption of CI particles by doping a SiBaFe alloy. Grain growth was effectively inhibited by the pinning effect of SiBaFe alloy nanoparticles at the grain boundaries. After heat treatment at 600 °C, the grain size of CI particles increased from ~10 nm to 85.1 nm, while that of CI/SiBaFe particles was only 32.0 nm; with the temperature rising to 700 °C, the grain size of CI particles sharply increased to 158.1 nm, while that of CI/SiBaFe particles was only 40.8 nm. Excellent stability in saturation magnetization and microwave absorption was also achieved in CI/SiBaFe particles. After heat treatment at 600 °C, the flaky CI/SiBaFe particles exhibited reflection loss below −10 dB over 7.01~10.11 GHz and a minimum of −14.92 dB when the thickness of their paraffin-based composite was 1.5 mm. We provided a low-cost and efficient kinetic strategy to stabilize the grain size in nanoscale and microwave absorption for nanocrystalline magnetic absorbents working at elevated temperature.

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High-Pressure Synthesis and Chemical Bonding of Barium Trisilicide BaSi3

Cited by 9 publications

References 52 publications

Chemically Assisted Precompression of Hydrogen Molecules in Alkaline-Earth Tetrahydrides

Chemically Assisted Precompression of Hydrogen Molecules in Alkaline-Earth Tetrahydrides

La₂Pd₃Ge₅ and Nd₂Pd₃Ge₅ Compounds: Chemical Bonding and Physical Properties

Enhanced Thermal Stability of Carbonyl Iron Nanocrystalline Microwave Absorbents by Pinning Grain Boundaries with SiBaFe Alloy Nanoparticles

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High-Pressure Synthesis and Chemical Bonding of Barium Trisilicide BaSi3

Cited by 9 publications

References 52 publications

Chemically Assisted Precompression of Hydrogen Molecules in Alkaline-Earth Tetrahydrides

Chemically Assisted Precompression of Hydrogen Molecules in Alkaline-Earth Tetrahydrides

La2Pd3Ge5 and Nd2Pd3Ge5 Compounds: Chemical Bonding and Physical Properties

Enhanced Thermal Stability of Carbonyl Iron Nanocrystalline Microwave Absorbents by Pinning Grain Boundaries with SiBaFe Alloy Nanoparticles

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La₂Pd₃Ge₅ and Nd₂Pd₃Ge₅ Compounds: Chemical Bonding and Physical Properties