Mg2NiH4
Magnesium nickel hydride · Mg2NiH4
Mg2NiH4 is a thermodynamically stable, semiconducting complex hydride used primarily for solid-state hydrogen storage applications.
About Magnesium nickel hydride
Magnesium nickel hydride is a semiconducting complex hydride recognized for its thermodynamic stability. As a member of the hydrogen storage hydride class, it serves as a critical material for reversible hydrogen uptake and release, benefiting from its position on the convex hull of stability.
The compound is extensively studied due to its structural diversity, with numerous reported crystalline arrangements. Its ability to store hydrogen efficiently makes it a focal point for research into solid-state hydrogen carriers and next-generation energy storage technologies.
Key Properties
Cross-validated computational properties for Magnesium nickel hydride, 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.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of Mg2NiH4. 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 Mg2NiH4, 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. |
|---|---|---|---|---|---|
| C2/c (No. 15) | monoclinic | 1.73 | 0.0000 | -0.286 | — |
| — | — | 1.58 | 0.0000 | -0.249 | — |
| C2/c (No. 15) | monoclinic | 1.57 | 0.0000 | -3.564 | 2.78 |
| Pccn (No. 56) | orthorhombic | 1.51 | 0.0045 | -3.559 | 2.75 |
| — | — | 1.27 | 0.0055 | -0.244 | — |
| Imm2 (No. 44) | orthorhombic | 0.39 | 0.0379 | -3.526 | 2.82 |
| C2/m (No. 12) | monoclinic | 0.00 | 0.1008 | -3.463 | 2.87 |
| — | — | 0.00 | 0.1051 | -0.144 | — |
| C2/m (No. 12) | monoclinic | — | — | — | 2.87 |
| Fm-3m (No. 225) | cubic | — | — | — | 2.68 |
| C2/c (No. 15) | monoclinic | — | — | — | 2.74 |
| Cc (No. 9) | monoclinic | — | — | — | 2.70 |
Synthesis Routes
Literature-extracted synthesis procedures targeting Mg2NiH4.
Applications
Where Magnesium nickel hydride is used.
Frequently Asked Questions
Common questions about Magnesium nickel hydride, answered from cross-validated data.
What is Mg2NiH4?
Mg2NiH4 is a thermodynamically stable, semiconducting complex hydride used primarily for solid-state hydrogen storage applications.
What is Mg2NiH4 used for?
What is the band gap of Mg2NiH4?
Is Mg2NiH4 a metal, semiconductor, or insulator?
Is Mg2NiH4 thermodynamically stable?
What is the crystal structure of Mg2NiH4?
What is the density of Mg2NiH4?
How many polymorphs of Mg2NiH4 are known?
How is Mg2NiH4 synthesized?
What elements does Mg2NiH4 contain?
Where does the data for Mg2NiH4 come from?
How It Compares
Within the hydrogen storage hydrides class.
Compared to simple binary hydrides like MgH2 or LiH, Mg2NiH4 offers unique structural complexity and distinct electronic behavior as a semiconductor. While simple hydrides often face challenges with kinetics and stability, this ternary hydride provides a more nuanced thermodynamic profile that helps bridge the gap between high-capacity storage and practical operational requirements.
Related Compounds
Other Hydrogen Storage Hydrides in the database.
Data sources & attribution
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- 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)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
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