Journal Article

PUBDB-2025-03882

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Unexpected compound reformation in the dense selenium-hydrogen system

Hu, H.Extern* ; Kuzovnikov, M. A.Extern* ; Shuttleworth, H. A.Extern* ; Marqueño, T. ; Yan, J. ; Osmond, I.Extern* ; Gorelli, F. A.Extern* ; Gregoryanz, E.Extern* ; Dalladay-Simpson, P.Extern* ; Ackland, G. J.Extern* ; Peña-Alvarez, M. ; Howie, R. (Corresponding author)Extern*

2025
Springer Nature London

This record in other databases:

Please use a persistent id in citations: doi:10.1038/s43246-025-00899-9  doi:10.3204/PUBDB-2025-03882

Abstract: The H$_2$Se molecule and the van der Waals compound (H$_2$Se)$_2$H$_2$ are both unstable upon room temperature compression, dissociating into their constituent elements above 22 GPa. Through a series of high pressure-high temperature diamond anvil cell experiments, we report the unexpected formation of a novel compound, SeH$_2$(H$_2$)$_2$ at pressures above 94 GPa. X-ray diffraction reveals the metallic sublattice to adopt a tetragonal (I4$_1$/amd) structure with density functional theory calculations finding a small distortion due to the orientation of H$_2$ molecules. The structure comprises of a network of zig-zag H-Se chains with quasi-molecular H$_2$ molecular units hosted in the prismatic Se interstices. Electrical resistance measurements demonstrate that SeH$_2$(H$_2$)$_2$ is non-metallic up to pressures of 148 GPa. Investigations into the Te-H system up to pressures of 165 GPa and 2000 K yielded no compound formation. The combined results suggest that the high pressure phase behavior of each chalcogen hydride is unique and more complex than previously thought.

---

Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
2. MetElOne - The Metallization Conditions of Element One (948895) (948895)
3. FS-Proposal: I-20230232 (I-20230232) (I-20230232)

Experiment(s):

1. PETRA Beamline P02.2 (PETRA III)

Appears in the scientific report 2025

---

Database coverage:
; ; ; ; Article Processing Charges ; Clarivate Analytics Master Journal List ; DOAJ Seal ; Emerging Sources Citation Index ; Fees ; IF >= 5 ; JCR ; SCOPUS ; Web of Science Core Collection

---