True Boundary for the Formation of Homoleptic Transition‐Metal Hydride Complexes |
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Authors: | Dr. Shigeyuki Takagi Yuki Iijima Dr. Toyoto Sato Dr. Hiroyuki Saitoh Dr. Kazutaka Ikeda Prof. Dr. Toshiya Otomo Dr. Kazutoshi Miwa Dr. Tamio Ikeshoji Dr. Katsutoshi Aoki Prof. Dr. Shin‐ichi Orimo |
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Affiliation: | 1. Institute for Materials Research, Tohoku University, Sendai 980‐8577 (Japan);2. Quantum Beam Science Directorate (Japan) Atomic Energy Agency, Hyogo 679‐5148 (Japan);3. Institute of Materials Science, High Energy Accelerator Research Organization, Tsukuba 305‐0801 (Japan);4. Toyota Central R&D Laboratories, Inc. Nagakute 480‐1192 (Japan);5. WPI‐Advanced Institute for Materials Research, Tohoku University, Sendai 980‐8577 (Japan) |
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Abstract: | Despite many exploratory studies over the past several decades, the presently known transition metals that form homoleptic transition‐metal hydride complexes are limited to the Groups 7–12. Here we present evidence for the formation of Mg3CrH8, containing the first Group 6 hydride complex [CrH7]5?. Our theoretical calculations reveal that pentagonal‐bipyramidal H coordination allows the formation of σ‐bonds between H and Cr. The results are strongly supported by neutron diffraction and IR spectroscopic measurements. Given that the Group 3–5 elements favor ionic/metallic bonding with H, along with the current results, the true boundary for the formation of homoleptic transition‐metal hydride complexes should be between Group 5 and 6. As the H coordination number generally tends to increase with decreasing atomic number of transition metals, the revised boundary suggests high potential for further discovery of hydrogen‐rich materials that are of both technological and fundamental interest. |
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Keywords: | chromium hydride ligands hydrides structure elucidations transition metals |
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