H4W
H4W is a metastable tungsten hydride compound that exhibits semimetallic electronic behavior.
About H4W
H4W is a tungsten hydride phase characterized by its near-zero-gap electronic structure, placing it in the category of semimetallic materials. Given its position above the thermodynamic hull, it is considered a metastable compound that exists under specific synthesis conditions.
This material is of significant interest in high-pressure physics and materials science, where researchers investigate the bonding behavior of hydrogen with transition metals. With multiple reported structures across various databases, it serves as a subject for understanding complex phase landscapes in hydride systems.
Key Properties
Cross-validated computational properties for H4W, aggregated across 4 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.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of H4W. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for H4W, 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. |
|---|---|---|---|---|---|
| P4/nmm (No. 129) | tetragonal | 0.03 | 0.1497 | -12.888 | 9.43 |
| — | — | 0.00 | 0.2466 | 0.247 | — |
| C2/m (No. 12) | monoclinic | — | — | — | 5.15 |
| P-1 (No. 2) | triclinic | — | — | — | 11.22 |
| P-1 (No. 2) | triclinic | — | — | — | 11.87 |
| P-1 (No. 2) | triclinic | — | — | — | 10.08 |
| P-1 (No. 2) | triclinic | — | — | — | 8.39 |
| C2 (No. 5) | monoclinic | — | — | — | 6.66 |
| Cm (No. 8) | monoclinic | — | — | — | 11.22 |
| Cm (No. 8) | monoclinic | — | — | — | 13.26 |
| C2/m (No. 12) | monoclinic | — | — | — | 6.16 |
| C2/m (No. 12) | monoclinic | — | — | — | 4.95 |
Applications
Where H4W is used.
Frequently Asked Questions
Common questions about H4W, answered from cross-validated data.
What is H4W?
H4W is a metastable tungsten hydride compound that exhibits semimetallic electronic behavior.
What is H4W used for?
What is the band gap of H4W?
Is H4W a metal, semiconductor, or insulator?
Is H4W thermodynamically stable?
What is the crystal structure of H4W?
What is the density of H4W?
How many polymorphs of H4W are known?
What elements does H4W contain?
Where does the data for H4W come from?
How It Compares
As a unique hydride phase, H4W represents a distinct point in the compositional space of tungsten-hydrogen systems, serving as a reference for studying the electronic transitions that occur in metal-rich hydrides.
Data sources & attribution
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- alexandria — Data from Alexandria. Cite: Schmidt et al., npj Comput. Mater. 10, 200 (2024). (CC-BY-4.0)
Analyze H4W in the Lattice Graph platform
Polymorph comparison, confidence scoring, supply-chain risk, and patent monitoring — across 85 source databases.
Explore the Platform →