Naming and classification
Physical properties
Reactions
Thermodynamic properties
Crystal structure
Atom properties
Electrochemical properties
Biological properties
Occurrence, isolation & synthesis
Isotopes
Safety
Uses
History
References
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Physical state @ 20°C: |
Gas [2] |
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Color: |
Colorless [2] |
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Odor: |
Almost odorless [2] |
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Molecular weight (g/mol): |
4.002602(2) [1] |
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Melting point (°C):  |
-272 [2] |
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Boiling point (°C): |
-268.93 [1] |
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Critical temperature (°C): |
3He: -269.826 [4]
4He: -267.9486 [4] |
|
Critical pressure (kPa): |
3He: 116.4 [4]
4He: 227.5 [4] |
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Density (g/cm3): |
Gas, 3He: 0.0001347 [4]
Gas, 4He: 0.00017850 [4]
Liquid, 3He: 0.589 [4]
Liquid, 4He: 0.1250 [4]
Critical, 3He: 0.000413 [4]
Critical, 4He: 0.0006964 [4] |
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Molar volume (cm3): |
57 (Critical) [3] |
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Refractive index: |
1.000035 (g)
1.028 (l) |
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Solubility: |
Water: 8.6 g/l (20 °C) [2]
Organic solvents: Insoluble (20 °C) [2] |
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