Properties of helium
Thermophysical properties for helium (CAS: 7440-59-7). Use the selector below to view properties in different unit systems.
Calculation Conditions
The following state-dependent properties were calculated at these standard conditions.
Temperature
25 °C
Pressure
1.01325 bar
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Open CalculatorIdentification
- AtomsHe: 1
- CAS7440-59-7
- FormulaHe
- ID7440-59-7
- InChIHe
- InChI KeySWQJXJOGLNCZEY-UHFFFAOYSA-N
- IUPAC Namehelium
- Molecular Weight (kg)4.0026
- Phaseg
- PubChem ID2.3987e+4
- SMILES[He]
- Synonyms
Physical Properties
- Acentric factor-0.3836
- Critical pressure (bar)2.2832
- Critical temperature (°C)-267.955
- Critical volume (m³/kmol)0.0575252
- Dipole moment0
- Melting temperature (°C)-272.2
- Normal boiling temperature (°C)-268.926
State-dependent Properties
- Compressibility factor1
- Density (kg/m³)0.163603
- Dynamic viscosity (cP)0.0198456
- Enthalpy of vaporization (mass) (kJ)0
- Enthalpy of vaporization (molar) (kJ/kmol)0
- Joule–Thomson coefficient4.2132e-13
- Kinematic viscosity1.2130e-4
- Molar enthalpy (kJ/kmol)0
- Molar heat capacity (kJ/(kmol·K))20.7861
- Molar volume (m³/kmol)24.4654
- Parachor
- Poynting correction factor
- Prandtl number0.66359
- Saturation pressure (bar)1.6261e+23
- Saturation temperature (°C)-268.926
- Solubility parameter
- Specific gravity0.138126
- Specific heat capacity (kJ/kg·K)5.19316
- Surface tension0
- Thermal conductivity0.155309
- Thermal diffusivity1.8280e-4
Safety Properties
- Autoignition temperature (°C)-273.15
- Flash point temperature (°C)-273.15
- Lower flammability limit
- Upper flammability limit0.235
Environmental Properties
- Global warming potential
- Ozone depletion potential
Failed Properties:
- API gravityFailed
- Gibbs free energy (kJ/kmol)Failed
- Molar entropy (kJ/(kmol·K))Failed
- Specific enthalpy (kJ)Failed
- Specific entropy (kJ/kg·K)Failed