Rb2MgH4
This compound is a complex metal hydride consisting of rubidium, magnesium, and hydrogen. It is primarily studied as a potential material for solid-state hydrogen storage due to its ability to release and absorb hydrogen under specific conditions.
Overview
Key Properties
Cross-validated computational properties for Rb2MgH4, 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.
3.31–4.01 eV
Range across DFT structures
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.
0.013 eV/atom
Best (lowest) across sources
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.
Near hull (likely stable)
2 DFT sources
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
22
3 databases, 2 space groups
Crystallography
Reported Structures
Lowest-energy structures reported for Rb2MgH4, 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. |
|---|---|---|---|---|---|
| Pnma (No. 62) | orthorhombic | 4.01 | 0.0133 | -2.747 | 2.23 |
| Cmcm (No. 63) | orthorhombic | 3.37 | 0.0830 | -2.678 | 1.74 |
| Pnma (No. 62) | orthorhombic | 3.31 | 0.0833 | -2.677 | 1.75 |
| Pnma (No. 62) | orthorhombic | 3.48 | 0.0844 | -2.676 | 1.72 |
| Pnma (No. 62) | orthorhombic | 3.34 | 0.1441 | -2.617 | 1.26 |
| Pnma (No. 62) | Orthorhombic | — | — | — | 1.27 |
| Cmcm (No. 63) | Orthorhombic | — | — | — | 1.74 |
| Pnma (No. 62) | Orthorhombic | — | — | — | 1.27 |
| Pnma (No. 62) | Orthorhombic | — | — | — | 2.29 |
| Pnma (No. 62) | Orthorhombic | — | — | — | 2.23 |
| Cmcm (No. 63) | — | — | — | — | — |
| Pnma (No. 62) | Orthorhombic | — | — | — | 1.73 |
Uses
Applications
Where Rb2MgH4 is used.
Hydrogen storage researchSolid-state chemistry studies
Reference
Frequently Asked Questions
Common questions about Rb2MgH4, answered from cross-validated data.
What is Rb2MgH4?
This compound is a complex metal hydride consisting of rubidium, magnesium, and hydrogen. It is primarily studied as a potential material for solid-state hydrogen storage due to its ability to release and absorb hydrogen under specific conditions.
What is Rb2MgH4 used for?
Rb2MgH4 is used in hydrogen storage research and solid-state chemistry studies.
What is the band gap of Rb2MgH4?
Rb2MgH4 has a DFT-computed band gap of 3.31–4.01 eV across 22 reported structures.
Is Rb2MgH4 a metal, semiconductor, or insulator?
With a wide band gap up to 4.01 eV it is an insulator / wide-band-gap material.
Is Rb2MgH4 thermodynamically stable?
Rb2MgH4 has a lowest energy above hull of 0.013 eV/atom (near hull (likely stable)).
What is the crystal structure of Rb2MgH4?
The lowest-energy reported polymorph of Rb2MgH4 is orthorhombic symmetry, space group Pnma (No. 62).
What is the density of Rb2MgH4?
The computed density of the ground-state structure of Rb2MgH4 is 2.23 g/cm³.
How many polymorphs of Rb2MgH4 are known?
22 structures of Rb2MgH4 are reported across 3 databases, spanning 2 distinct space groups.
What elements does Rb2MgH4 contain?
Rb2MgH4 contains H, Mg, and Rb (3 elements).
Where does the data for Rb2MgH4 come from?
Rb2MgH4 data is cross-referenced from materials_project, mpaloe, jarvis.
Explore
Related Compounds
Other Hydrogen Storage Hydrides in the database.
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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