Mg5H8O9
Mg5H8O9 is a stable, wide-band-gap insulating compound composed of magnesium, oxygen, and hydrogen.
About Mg5H8O9
Mg5H8O9 is a complex hydrogen-containing magnesium oxide that exists as a thermodynamically stable phase on the convex hull. Its electronic character is defined by a wide band gap, classifying it as a robust insulating material suitable for applications where electrical conductivity must be minimized.
Because it is a stable inorganic compound, it serves as a fundamental building block in structural investigations of magnesium-based systems. Its existence across multiple databases highlights its significance as a well-defined crystalline phase within the broader landscape of metal-oxygen-hydrogen materials.
Key Properties
Cross-validated computational properties for Mg5H8O9, 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 Mg5H8O9. 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 Mg5H8O9, 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. |
|---|---|---|---|---|---|
| P-3m1 (No. 164) | trigonal | 3.57 | 0.0002 | -5.726 | 2.57 |
| — | — | 4.21 | 0.0106 | -1.995 | — |
| P-3m1 (No. 164) | trigonal | 4.09 | 0.0121 | -1.943 | — |
| P-3m1 (No. 164) | trigonal | — | — | — | 2.33 |
| P-3m1 (No. 164) | trigonal | — | — | — | 2.40 |
| P-3m1 (No. 164) | trigonal | — | — | — | 2.42 |
| P-3m1 (No. 164) | trigonal | — | — | — | 2.48 |
Applications
Where Mg5H8O9 is used.
Frequently Asked Questions
Common questions about Mg5H8O9, answered from cross-validated data.
What is Mg5H8O9?
Mg5H8O9 is a stable, wide-band-gap insulating compound composed of magnesium, oxygen, and hydrogen.
What is Mg5H8O9 used for?
What is the band gap of Mg5H8O9?
Is Mg5H8O9 a metal, semiconductor, or insulator?
Is Mg5H8O9 thermodynamically stable?
What is the crystal structure of Mg5H8O9?
What is the density of Mg5H8O9?
How many polymorphs of Mg5H8O9 are known?
What elements does Mg5H8O9 contain?
Where does the data for Mg5H8O9 come from?
How It Compares
As a unique phase within the magnesium-oxygen-hydrogen system, Mg5H8O9 represents a distinct structural arrangement that maintains thermodynamic stability, serving as a reference point for understanding the phase space of hydrated magnesium oxides.
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)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- cod — Data from the Crystallography Open Database (crystallography.net/cod/). Cite: Grazulis et al., J. Appl. Cryst. 42, 726 (2009). (CC0-1.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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