Hydrogen and Electron as Anion and Their Effect on Materials Properties

Ionic compounds consist of cations and anions. In conventional materials, an element with low electronegativity forms an anion such as oxygen and halogen. However, recent studies have revealed that hydrogen and electron as an anion are often present in the stable solid compounds, i.e., hydride and electride. Since hydrogen is the most common impurity and the ionic radius of H^- is similar to O^2- and F^-. Thus H^- often occupies the oxygen/fluorine sites but their occurrence is disregarded because of very small X-ray scattering factor.<br/>This talk focuses on the presence of critical role of hydride and electron anion in complex solids and their effects on materials properties listed below;<br/><br/>a.Hydrogen as electron donor<br/>b.Hydride as fast ion conducting species<br/>c.Role of H^- in IBSCs and Nickelate superconductors<br/>d. Electrides and their applications.<br/><br/><br/><br/><b>Reference:</b><br/>[1] Hosono, H., & Kitano, M. (2021). Advances in materials and applications of inorganic electrides. Chemical Reviews, 121(5), 3121-3185.<br/>[2] Hosono, H., & Kumomi, H. (Eds.). (2022). Amorphous Oxide Semiconductors: IGZO and Related Materials for Display and Memory. John Wiley & Sons.<br/>[3] Fukui, K., Iimura, S., Iskandarov, A., Tada, T., & Hosono, H. (2022). Room-temperature fast H^– conduction in oxygen-substituted lanthanum hydride. Journal of the American Chemical Society, 144(4), 1523-1527.<br/>[4]Hosono, H., Yamamoto, A., Hiramatsu, H., & Ma, Y. (2018). Recent advances in iron-based superconductors toward applications. Materials today, 21(3), 278-302.<br/>[5] Ding, X., Tam, C. C., Sui, X., Zhao, Y., Xu, M., Choi, J., ... & Qiao, L. (2023). Critical role of hydrogen for superconductivity in nickelates. Nature, 615(7950), 50-55.