Materials under high pressure: a chemical perspective

Hilleke, Katerina P.; Bi, Tiange; Zurek, Eva

doi:10.1007/s00339-022-05576-z

Cited by 22 publications

(8 citation statements)

References 298 publications

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“…In the conventional materials, high-pressure polymorphs are denser than ambient-pressure polymorphs (e.g., diamond vs graphite). 50 However, the high-pressure phase β-Sr 2 LiHOCl 2 has a slightly higher cell volume compared to the normalized value for the low-pressure phase α-Sr 2 LiHOCl 2 (245.797(4) Å 3 vs 245.092(3) Å 3 ). One should notice, however, that the SXRD pattern of β-Sr 2 LiHOCl 2 was measured at ambient pressure, not at the synthetic pressure.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Pressure-Induced Anion Order–Disorder Transition in Layered Perovskite Sr₂LiHOCl₂

et al. 2023

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While cation order–disorder transitions have been extensively investigated because of their decisive impact on chemical and physical properties, only few anion order–disorder transitions are known. Here, we show that Sr2CuO2Cl2-type layered perovskite Sr2LiHOCl2 exhibits a pressure-induced H–/O2– order–disorder transition. When synthesized at ambient and low pressures (≤2 GPa), Sr2LiHOCl2 is isostructural to orthorhombic Eu2LiHOCl2 (Cmcm) with a H–/O2– order at the equatorial sites. However, applying a higher pressure (5 GPa) during synthesis causes the equatorial anions to be disordered, leading to a tetragonal symmetry (I4/mmm) with a loss of the superstructure. The structural analysis revealed that, in the ambient pressure phase, HLi2Sr4 and OLi2Sr4 octahedra have distinct sizes to stabilize otherwise underbonded oxide ions, which is less important at the higher pressure. Anion-disordered Sr2LiHOBr2 and Ba2LiHOCl2 were also obtained at 5 GPa. Given the abundant layer-type anion order in perovskite-based oxyhydrides (e.g., La2LiHO3), the inclusion of additional anions (e.g., chloride) expands the frontiers of anion ordering patterns and their distribution control with the benefit of improving ionic conduction in solids.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Pressure-Induced Anion Order–Disorder Transition in Layered Perovskite Sr₂LiHOCl₂

et al. 2023

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“…Numerous studies have shown that compression of interatomic distances has a significant impact on the optical, magnetic and transport properties of materials through substantial modification of their bonding pattern. [1][2][3][4] Numerous high-pressure investigations have focused their attention on studying diatomic molecules such as H 2 , N 2 , O 2 , and the halogens, [5][6][7] which in the solid state form molecular crystals held by weak intermolecular forces. However, compression leads to substantial alteration of the bonding pattern of these elements, as evidenced by the molecular dissociation of iodine and bromine, 8,9 or the predicted polymerization of fluorine.…”

Section: Introductionmentioning

confidence: 99%

High-pressure stabilization of open–shell bromine fluorides

Dalsaniya,

Upadhyay,

Jan Kurzydłowski

et al. 2024

Phys. Chem. Chem. Phys.

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“…The latter breakthrough can be directly traced back to Ashcroft's proposal that hydrogen-rich alloys, metallized at conditions of extreme pressure, albeit less extreme than those required to metallize pure hydrogen, would be high-temperature phonon-mediated superconductors [7]. It also marked a paradigm shift defined by a close synergy between theory and experiment, with computations either predicting the most promising superconducting phases or being instrumental in characterizing the synthesized compounds [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Structure, Stability and Superconductivity of N-doped Lutetium Hydrides at kbar Pressures

Hilleke¹,

Wang²,

Luo³

et al. 2023

Preprint

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The structure of the material responsible for the room temperature and near ambient pressure superconductivity reported in an N-doped lutetium hydride [Nature, 615, 244 (2023)] has not been conclusively determined. Herein, density functional theory calculations are performed in an attempt to uncover what it might be. Guided by a range of strategies including crystal structure prediction and modifications of existing structure types, we present an array of Lu-N-H phases that are dynamically stable at experimentally relevant pressures. Although none of the structures found are thermodynamically stable, and none are expected to remain superconducting above ∼17 K at 10 kbar, a number of metallic compounds with fcc Lu lattices -as suggested by the experimental X-ray diffraction measurements of the majority phase -are identified. The system whose calculated equation of states matches best with that measured for the majority phase is fluorite-type LuH2, whose 10 kbar superconducting critical temperature was estimated to be 0.09 K using the Allen-Dynes modified McMillan equation.

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Materials under high pressure: a chemical perspective

Cited by 22 publications

References 298 publications

Pressure-Induced Anion Order–Disorder Transition in Layered Perovskite Sr₂LiHOCl₂

Pressure-Induced Anion Order–Disorder Transition in Layered Perovskite Sr₂LiHOCl₂

High-pressure stabilization of open–shell bromine fluorides

Structure, Stability and Superconductivity of N-doped Lutetium Hydrides at kbar Pressures

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Materials under high pressure: a chemical perspective

Cited by 22 publications

References 298 publications

Pressure-Induced Anion Order–Disorder Transition in Layered Perovskite Sr2LiHOCl2

Pressure-Induced Anion Order–Disorder Transition in Layered Perovskite Sr2LiHOCl2

High-pressure stabilization of open–shell bromine fluorides

Structure, Stability and Superconductivity of N-doped Lutetium Hydrides at kbar Pressures

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Product

Resources

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Pressure-Induced Anion Order–Disorder Transition in Layered Perovskite Sr₂LiHOCl₂

Pressure-Induced Anion Order–Disorder Transition in Layered Perovskite Sr₂LiHOCl₂