Cohesion of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Ba</mml:mi><mml:mi mathvariant="normal">Re</mml:mi><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mn>9</mml:mn></mml:msub></mml:mrow></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Ba</mml:mi><mml:mi mathvariant="normal">Mn</mml:mi><mml:msub><mml:mi mathvariant="normal">H</mml:mi><mml:mn>9</mml:mn></

Singh, David J.; Gupta, Michèle; Gupta, R. S.

doi:10.1103/physrevb.75.035103

Cited by 16 publications

(13 citation statements)

References 28 publications

(27 reference statements)

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“…These states strongly hybridize with the T spd states to form the σ -bonds, which is evident from the H1 s and T spd characters of both the valence and conduction bands. These results are consistent with a previous electronic structure calculation by Singh et al 29. for BaReH 9 , which contains the hydride complex ReH 9 .…”

Section: Resultssupporting

confidence: 93%

Formation of novel transition metal hydride complexes with ninefold hydrogen coordination

Takagi

Iijima

Sato

et al. 2017

Sci Rep

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Ninefold coordination of hydrogen is very rare, and has been observed in two different hydride complexes comprising rhenium and technetium. Herein, based on a theoretical/experimental approach, we present evidence for the formation of ninefold H- coordination hydride complexes of molybdenum ([MoH9]3−), tungsten ([WH9]3−), niobium ([NbH9]4−) and tantalum ([TaH9]4−) in novel complex transition-metal hydrides, Li5MoH11, Li5WH11, Li6NbH11 and Li6TaH11, respectively. All of the synthesized materials are insulated with band gaps of approximately 4 eV, but contain a sufficient amount of hydrogen to cause the H 1s-derived states to reach the Fermi level. Such hydrogen-rich materials might be of interest for high-critical-temperature superconductivity if the gaps close under compression. Furthermore, the hydride complexes exhibit significant rotational motions associated with anharmonic librations at room temperature, which are often discussed in relation to the translational diffusion of cations in alkali-metal dodecahydro-closo-dodecaborates and strongly point to the emergence of a fast lithium conduction even at room temperature.

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Section: Resultssupporting

confidence: 93%

Formation of novel transition metal hydride complexes with ninefold hydrogen coordination

Takagi

Iijima

Sato

et al. 2017

Sci Rep

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“…[20][21] The hydrogen density in BaReH 9 (134 g/L) is approximately twice that of liquid hydrogen at ambient pressure, indicating that hydrogen atom is chemically precompressed. [20][21][22][23][24] Markopoulous et al 23 examined theoretically the high pressure behavior of BaReH 9 and predicted that metallization occurs at 115 GPa assuming the crystal structure of BaReH 9 remains in the ambient pressure structure.…”

Section: Introductionmentioning

confidence: 99%

“…As the most hydrogen-rich stoichiometric metal salt, BaReH 9 crystallizes with ionic bonding between Ba 2+ and ReH 9 2– in the hexagonal NiAs-type structure with respect to the Ba and Re positions (space group P 6 3 / mmc, Z = 2; Figure ). , The hydrogen density in BaReH 9 (134 g/L) is approximately twice that of liquid hydrogen at ambient pressure, indicating that the hydrogen atoms are chemically precompressed. − Markopoulos et al examined theoretically the high-pressure behavior of BaReH 9 and predicted that metallization occurs at 115 GPa, assuming that the crystal structure of BaReH 9 remains in the ambient-pressure structure.…”

Section: Introductionmentioning

confidence: 99%

Metallization and Superconductivity in the Hydrogen-Rich Ionic Salt BaReH₉

et al. 2015

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BaReH 9 is an exceedingly high hydrogen content metal hydride that is predicted to exhibit interesting behavior under pressure. The high-pressure electronic properties of this material were investigated using diamond-anvil cell electrical conductivity techniques to megabar (100 GPa) pressures. The measurements show that BeReH 9 transforms to a metal and then superconductor above 100 GPa with a maximum T c near 7 K. The occurrence of superconductivity is confirmed by the suppression of the resistance drop on application of magnetic fields. The transition to the metallic phase is sluggish, but is accelerated by laser irradiation. Raman scattering and x-ray diffraction measurements, used to supplement the electrical measurements, indicate that the Ba-Re sublattice is largely preserved on compression at the conditions explored, but there is a possibility that hydrogen atoms are gradually disordered under pressure. This is suggested from sharpening of peaks of Raman spectroscopy and x-ray diffraction by heat treatment as well as temperature dependence of resistance under pressure. The data suggest that the transition to the superconducting state is first order. The possibility that the transition is associated with the breakdown of BeReH 9 is discussed.

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“…Inspired by the discovery of K 2 ReH 9 , other types of cations have been used to extend the [ReH 9 ] 2– family, including Na 2 ReH 9 , NaKReH 9 , ((C 2 H 5 ) 4 N) 2 ReH 9 , and BaReH 9 . , For elements of group VII, K 2 TcH 9 is the only known technetium compound incorporating similar nine-coordinate [TcH 9 ] 2– units . No analogous manganese compound has yet been reported, while theoretical studies have suggested its viability. , Among the above-mentioned compounds, BaReH 9 has the highest (4.5:1) hydrogen to metal ratio. Unfortunately, because of the high atomic weight of the metal atoms, the hydrogen content is only 2.7 wt %, too small for use as a hydrogen storage material …”

Section: Introductionmentioning

confidence: 99%

The Remarkable [ReH₉]^2– Dianion: Molecular Structure and Vibrational Frequencies

Agarwal

Schaefer

2014

J. Phys. Chem. B

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The equilibrium geometries and vibrational frequencies of the extraordinary [ReH9](2-) dianion (D3h symmetry) are investigated using Hartree-Fock (HF) theory, coupled cluster theory with single and double excitations (CCSD), and coupled cluster theory with single, double, and perturbative triple excitations [CCSD(T)]. The new generation of energy-consistent relativistic pseudopotentials and correlation consistent basis sets [cc-pVXZ-PP (Re) and cc-pVXZ (H) (X = D, T, Q)] are used. Anharmonicity was considered using second-order vibrational perturbation theory. The predicted geometries and vibrational frequencies generally agree with experimental findings. In order to stabilize the [ReH9](2-) dianion, the M2ReH9 (M = Na, K) sandwich complexes (D3h symmetry) are studied at the CCSD(T)/VTZ (VTZ = cc-pVTZ-PP (Re) and cc-pVTZ (H, Na, K)) level of theory. Compared to the [ReH9](2-) dianion, the predicted vibrational frequencies involving Re-H stretching modes are improved, indicating the importance of considering counterions in electronically dense systems. The natural bond orbital analysis shows that each H atom only bonds with the Re center, and the 5d orbitals of Re and 1s orbitals of H are major factors for the covalent Re-H bonding.

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Cohesion ofBaReH9andBaMnH9

Cited by 16 publications

References 28 publications

Formation of novel transition metal hydride complexes with ninefold hydrogen coordination

Formation of novel transition metal hydride complexes with ninefold hydrogen coordination

Metallization and Superconductivity in the Hydrogen-Rich Ionic Salt BaReH₉

The Remarkable [ReH₉]^2– Dianion: Molecular Structure and Vibrational Frequencies

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Cohesion ofBaReH9andBaMnH9

Cited by 16 publications

References 28 publications

Formation of novel transition metal hydride complexes with ninefold hydrogen coordination

Formation of novel transition metal hydride complexes with ninefold hydrogen coordination

Metallization and Superconductivity in the Hydrogen-Rich Ionic Salt BaReH9

The Remarkable [ReH9]2– Dianion: Molecular Structure and Vibrational Frequencies

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Metallization and Superconductivity in the Hydrogen-Rich Ionic Salt BaReH₉

The Remarkable [ReH₉]^2– Dianion: Molecular Structure and Vibrational Frequencies