In-column Synthesis and Atomic-resolution Electron Microscopic Analysis of Metastable Reactive Nitrides
8 affiliations
- 1Institute of Low Temperature Science
- 2Hokkaido University
- 3Center for Basic Research on Materials
- 4National Institute for Materials Science
- 5Research Center for Autonomous Systems Materialogy
- 6Institute of Science Tokyo
- 7Graduate School of Science
- 8Faculty of Science
Abstract
Metastable and air-sensitive compounds are challenging to synthesize and characterize because their formation often requires harsh conditions and their structures can rapidly evolve upon exposure to the environment. Here, we demonstrate that a high-vacuum environment inside a transmission electron microscope (TEM) column can serve simultaneously as a reaction platform and an atomic-scale analytical tool for generating and interrogating such materials. Electron-beam irradiation on sodium azide (NaN3) produces crystalline sodium nitride (Na3N) at room temperature, despite the conventional decomposition of NaN3 into sodium and nitrogen. The formation of Na3N is supported by high-resolution TEM, electron diffraction, and energy dispersive X-ray spectroscopy, which reveal correlated structural and compositional changes through irradiation. The resulting Na3N subsequently undergoes oxidation through an amorphous intermediate to form polycrystalline Na2O. The high-vacuum environment sufficiently suppresses this reaction to resolve its otherwise unachievable microscopic mechanisms. Extending this approach to potassium azide (KN3), we observe a transient crystalline phase that is most consistently indexed as K3N, a nitride known to be thermally unstable even under room temperature. Its transient appearance and decay indicate a dynamic balance between electron-beam-induced formation and degradation. These results establish in-column electron-beam chemistry as a route to metastable nitride formation while enabling multimodal characterization of highly reactive products. More broadly, this strategy offers a means of exploring nonequilibrium metastable compounds that are difficult to access using conventional synthesis and characterization workflows.
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BibTeX
@misc{sakakibara2026incolumn,
title = {{In-column Synthesis and Atomic-resolution Electron Microscopic Analysis of Metastable Reactive Nitrides}},
author = {Masaya Sakakibara and Koji Harano and Ryusei Kudo and Jun Kawano and Tomoya Yamazaki and Yuki Kimura},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009604/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009604/v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - In-column Synthesis and Atomic-resolution Electron Microscopic Analysis of Metastable Reactive Nitrides
AU - Masaya Sakakibara
AU - Koji Harano
AU - Ryusei Kudo
AU - Jun Kawano
AU - Tomoya Yamazaki
AU - Yuki Kimura
PY - 2026
DA - 2026/09/29
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009604/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009604/v1
AB - Metastable and air-sensitive compounds are challenging to synthesize and characterize because their formation often requires harsh conditions and their structures can rapidly evolve upon exposure to the environment. Here, we demonstrate that a high-vacuum environment inside a transmission electron microscope (TEM) column can serve simultaneously as a reaction platform and an atomic-scale analytical tool for generating and interrogating such materials. Electron-beam irradiation on sodium azide (NaN3) produces crystalline sodium nitride (Na3N) at room temperature, despite the conventional decomposition of NaN3 into sodium and nitrogen. The formation of Na3N is supported by high-resolution TEM, electron diffraction, and energy dispersive X-ray spectroscopy, which reveal correlated structural and compositional changes through irradiation. The resulting Na3N subsequently undergoes oxidation through an amorphous intermediate to form polycrystalline Na2O. The high-vacuum environment sufficiently suppresses this reaction to resolve its otherwise unachievable microscopic mechanisms. Extending this approach to potassium azide (KN3), we observe a transient crystalline phase that is most consistently indexed as K3N, a nitride known to be thermally unstable even under room temperature. Its transient appearance and decay indicate a dynamic balance between electron-beam-induced formation and degradation. These results establish in-column electron-beam chemistry as a route to metastable nitride formation while enabling multimodal characterization of highly reactive products. More broadly, this strategy offers a means of exploring nonequilibrium metastable compounds that are difficult to access using conventional synthesis and characterization workflows.
ER -