He
Helium · He
Helium is a chemically inert, monatomic noble gas that serves as a vital resource for cryogenic cooling and specialized industrial processes.
About Helium
Helium is a noble gas that exists as a monatomic, colorless, and odorless element. As a wide-gap insulator, it is characterized by its exceptional chemical stability and resistance to forming compounds under standard conditions, positioning it as a fundamental reference point for inert matter.
Its thermodynamic stability on the convex hull underscores its status as one of the most chemically unreactive elements in the periodic table. This unique electronic character makes it an indispensable medium for high-precision scientific instrumentation and industrial cooling applications where chemical purity is paramount.
Key Properties
Cross-validated computational properties for Helium, aggregated across 5 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 He. 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 He, 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 | 18.18 | 0.0000 | -0.014 | — |
| P63/mmc (No. 194) | hexagonal | 18.10 | 0.0000 | -0.015 | — |
| P63/mmc (No. 194) | hexagonal | 18.09 | 0.0000 | -0.015 | — |
| Fm-3m (No. 225) | cubic | 17.97 | 0.0000 | 0.005 | — |
| Im-3m (No. 229) | cubic | 17.84 | 0.0000 | 0.000 | — |
| P63/mmc (No. 194) | hexagonal | 17.73 | 0.0000 | 0.000 | — |
| Im-3m (No. 229) | cubic | 17.64 | 0.0000 | -0.314 | 0.38 |
| — | — | 16.81 | 0.0000 | 0.000 | — |
| P6/mmm (No. 191) | hexagonal | 16.59 | 0.0000 | 0.005 | — |
| P63/mmc (No. 194) | hexagonal | 17.77 | 0.0015 | -0.312 | 0.41 |
| Fm-3m (No. 225) | cubic | 17.89 | 0.0027 | -0.311 | 0.42 |
| P6/mmm (No. 191) | hexagonal | 16.59 | 0.0036 | -0.310 | 0.36 |
Applications
Where Helium is used.
Frequently Asked Questions
Common questions about Helium, answered from cross-validated data.
What is He?
Helium is a chemically inert, monatomic noble gas that serves as a vital resource for cryogenic cooling and specialized industrial processes.
What is He used for?
What is the band gap of He?
Is He a metal, semiconductor, or insulator?
Is He thermodynamically stable?
What is the crystal structure of He?
How many polymorphs of He are known?
What elements does He contain?
Where does the data for He come from?
How It Compares
As a singular noble gas, Helium serves as the definitive benchmark for chemical inertness and insulating behavior against which other elements and compounds are measured.
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)
- 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)
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