Hydrogen-rich hydrides attract great attention due to recent theoretical (1) and then experimental discovery of record high-temperature superconductivity in H₃S [T_c = 203 K at 155 GPa (2)]. Here we search for stable uranium hydrides at pressures up to 500 GPa using ab initio evolutionary crystal structure prediction. Chemistry of the U-H system turned out to be extremely rich, with 14 new compounds, including hydrogen-rich UH₅, UH₆, U₂H₁₃, UH₇, UH₈, U₂H₁₇, and UH₉. Their crystal structures are based on either common face-centered cubic or hexagonal close-packed uranium sublattice and unusual H₈ cubic clusters. Our high-pressure experiments at 1 to 103 GPa confirm the predicted UH₇, UH₈, and three different phases of UH₅, raising confidence about predictions of the other phases. Many of the newly predicted phases are expected to be high-temperature superconductors. The highest-T_c superconductor is UH₇, predicted to be thermodynamically stable at pressures above 22 GPa (with T_c = 44 to 54 K), and this phase remains dynamically stable upon decompression to zero pressure (where it has T_c = 57 to 66 K).

中文翻译：

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中等压力下的氢化铀：预测、合成和预期的超导性。

由于最近的理论 ( 1 ) 和随后的实验发现 H ₃ S中创纪录的高温超导性[ T _c = 203 K at 155 GPa ( 2 )]，富氢氢化物引起了极大的关注。在这里，我们使用从头进化晶体结构预测在高达 500 GPa 的压力下寻找稳定的氢化铀。UH系统的化学成分极其丰富，有14种新化合物，包括富氢UH ₅、UH ₆、U ₂ H ₁₃、UH ₇、UH ₈、U ₂ H ₁₇和UH ₉。它们的晶体结构基于常见的面心立方或六方密排铀亚晶格和不寻常的 H ₈立方簇。我们在 1 至 103 GPa 的高压实验证实了预测的 UH ₇、UH _{8和 UH 5}的三个不同相，提高了对其他相预测的信心。许多新预测的相预计将是高温超导体。T _c最高的超导体是 UH ₇，预计在高于 22 GPa 的压力下具有热力学稳定（T _c = 44 至 54 K），并且该相在减压到零压力（其中T _c = 57 ）时保持动态稳定。至 66 K）。