Pressure-Induced Transformations in Diborane: A Raman Spectroscopic Study

Murli, Chitra; Song, Yang

doi:10.1021/jp906261s

Cited by 23 publications

(47 citation statements)

References 45 publications

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“…Raman spectroscopy has been employed to study diborane up to 24 GPa. 211 At 4 GPa the system underwent a liquid-solid transition to phase I, followed by a transformation to phase II at 6 GPa, and phase III at 14 GPa. The phase transitions were reversible upon decompression.…”

Section: Group 13: Icosagen Hydrides Boronmentioning

confidence: 98%

The Search for Superconductivity in High Pressure Hydrides

Zarifi

Terpstra

et al. 2019

Reference Module in Chemistry, Molecular Sciences and Chemical Engineering

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The computational and experimental exploration of the phase diagrams of binary hydrides under high pressure has uncovered phases with novel stoichiometries and structures, some which are superconducting at quite high temperatures. Herein we review the plethora of studies that have been undertaken in the last decade on the main group and transition metal hydrides, as well as a few of the rare earth hydrides at pressures attainable in diamond anvil cells. The aggregate of data shows that the propensity for superconductivity is dependent upon the species used to "dope" hydrogen, with some of the highest values obtained for elements that belong to the alkaline and rare earth, or the pnictogen and chalcogen families.

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Section: Group 13: Icosagen Hydrides Boronmentioning

confidence: 98%

The Search for Superconductivity in High Pressure Hydrides

Zarifi

Terpstra

et al. 2019

Reference Module in Chemistry, Molecular Sciences and Chemical Engineering

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“…11 Over the last decade, the high-pressure behavior and properties of NH 3 BH 3 have been studied by several groups. [13][14][15][16][17][18][19][20][21][22][23][24] The earliest studies 13,14 were basically motivated by the anomalous lattice stability of NH 3 BH 3 , which is a solid at room temperature in contrast to the very similar compounds diborane, B 2 H 6 (liquid 25 up to 4 GPa) and ethane, C 2 H 6 (gas). The reason for this stability is believed to be the existence of dihydrogen bonds between NH 3 BH 3 molecules.…”

Section: Introductionmentioning

confidence: 99%

Phase coexistence and hysteresis effects in the pressure-temperature phase diagram of NH3BH3

Andersson

Filinchuk

Dmitriev³

et al. 2011

Phys. Rev. B

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The potential hydrogen storage compound NH 3 BH 3 has three known structural phases in the temperature and pressure ranges 110-300 K and 0-1.5 GPa, respectively. We report here the boundaries between, and the ranges of stability of, these phases. The phase boundaries were located by in situ measurements of the thermal conductivity, while the actual structures in selected areas were identified by in situ Raman spectroscopy and x-ray diffraction. Below 0.6 GPa, reversible transitions involving only small hysteresis effects occur between the room-temperature tetragonal plastic crystal I4mm phase and the low-temperature orthorhombic Pmn2 1 phase. Transformations of the I4mm phase into the high-pressure orthorhombic Cmc2 1 phase, occurring above 0.8 GPa, are associated with very large hysteresis effects, such that the reverse transition may occur at up to 0.5 GPa lower pressures. Below 230 K, a fraction of the Cmc2 1 phase is metastable to atmospheric pressure, suggesting the possibility that dense structural phases of NH 3 BH 3 , stable at room temperature, could possibly be created and stabilized by alloying or by other methods. Mixed orthorhombic Pmn2 1 /Cmc2 1 phases were observed in an intermediate pressure-temperature range, but a fourth structural phase predicted by Filinchuk et al. [Phys. Rev. B 79, 214111 (2009)] was not observed in the pressure-temperature ranges of this experiment. The thermal conductivity of the plastic crystal I4mm phase is about 0.6 W m −1 K −1 and only weakly dependent on temperature, while the ordered orthorhombic phases have higher thermal conductivities limited by phonon-phonon scattering.

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“…High-pressure experimental and theoretical studies have shown that compressed diborane undergoes a sequence of phase transitions. With increasing pressure to 50 GPa, several structural transitions have been identified in recent spectroscopic experiments [8,9]. However, no detailed experimental structural data are yet available for these high-pressure phases.…”

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confidence: 99%