BaReH9
BaReH9 is a thermodynamically stable, wide-band-gap insulating compound composed of barium, rhenium, and hydrogen.

About BaReH9
BaReH9 is a complex hydride characterized by its wide-band-gap insulating electronic profile. As a material residing on the convex hull, it exhibits significant thermodynamic stability, making it a subject of interest for fundamental studies in inorganic chemistry and solid-state physics. The compound's structural complexity is underscored by the high number of reported configurations across multiple databases, reflecting its intricate atomic arrangement. Its unique composition involving barium and rhenium highlights the diverse potential of metal-hydrogen systems in exploring unconventional bonding environments. This material serves as a critical reference point for understanding the stability and electronic behavior of heavy-metal hydrides, providing insights into how structural geometry influences insulating properties. Its robust nature suggests potential utility in specialized applications where high structural integrity is required.
Key Properties
Cross-validated computational properties for BaReH9, aggregated across 3 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Reported Structures
Lowest-energy structures reported for BaReH9, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| P63/mmc (No. 194) | hexagonal | 3.83 | 0.0000 | -4.502 | 4.82 |
| Cmcm (No. 63) | orthorhombic | 3.89 | 0.0055 | -4.497 | 4.82 |
| P21/m (No. 11) | monoclinic | 3.71 | 0.0154 | -4.487 | 4.75 |
| Cmcm (No. 63) | orthorhombic | 3.74 | 0.0215 | -4.481 | 4.73 |
| R32 (No. 155) | trigonal | 3.01 | 0.0669 | -4.435 | 5.07 |
| P3 (No. 143) | trigonal | 3.12 | 0.0738 | -4.428 | 4.97 |
| P21/m (No. 11) | monoclinic | 0.13 | 0.2310 | -4.271 | 5.66 |
| P21/m (No. 11) | monoclinic | 0.35 | 0.2326 | -4.270 | 5.51 |
| R32 (No. 155) | Trigonal | — | — | — | 5.07 |
| P21/m (No. 11) | — | — | — | — | — |
| P63/mmc (No. 194) | Hexagonal | — | — | — | 4.77 |
| R32 (No. 155) | Trigonal | — | — | — | 5.11 |
Applications
Where BaReH9 is used.
Frequently Asked Questions
Common questions about BaReH9, answered from cross-validated data.
What is BaReH9?
BaReH9 is a thermodynamically stable, wide-band-gap insulating compound composed of barium, rhenium, and hydrogen.
What is BaReH9 used for?
What is the band gap of BaReH9?
Is BaReH9 a metal, semiconductor, or insulator?
Is BaReH9 thermodynamically stable?
What is the crystal structure of BaReH9?
What is the density of BaReH9?
How many polymorphs of BaReH9 are known?
What elements does BaReH9 contain?
Where does the data for BaReH9 come from?
How It Compares
As a highly stable, insulating complex hydride, BaReH9 stands as a unique representative of its class, serving as a benchmark for the structural and electronic behavior of ternary metal hydrides.
Data sources & attribution
- materials_project — Data from the Materials Project. Cite: Jain et al., APL Materials 1, 011002 (2013).
- mpaloe — Data from mpaloe.
- jarvis — Data from JARVIS (NIST). Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020).
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