Properties of Argon (Ar)
Argon is a chemical element with the symbol “Ar” and atomic number 18. It is a colorless, odorless, and inert gas that makes up a small fraction of the Earth’s atmosphere. Argon is used in various industrial applications, including as a shielding gas in welding, in the production of certain metals, and as a filler gas in various types of lighting, such as fluorescent and neon lights.
The following table provides a comprehensive list of argon properties in both SI and US customary/Imperial units at normal temperature and pressure (NTP).
Click on the icon to switch between Metric and Imperial units.
| Physical Properties | Metric |
|---|---|
| Molar Mass | 39.948 g/mol |
| Density (0°C) | 1.784 kg/m3 |
| Dynamic Viscosity (25°C) | 22.7 µPa·s |
| Speed of Sound in Gas (27°C) | 323 m/s |
| Thermal Properties | Metric |
| Melting Point | -189.3 °C |
| Boiling Point | -185.9 °C |
| Thermal Conductivity (25°C) | 0.0177 W/m·K |
| Specific Heat Capacity (Cp) | 520 J/kg·K |
| Critical Constants | Metric |
| Critical Temperature (Tc) | -122.4 °C |
| Critical Pressure (Pc) | 4.86 MPa |
| Critical Density (ρc) | 530 kg/m3 |
| Electrical Properties | Metric |
| Relative Permittivity (εr) | 1.000545 |
| Optical Properties | Metric |
| Refractive Index (589 nm) | 1.000281 |
Unless stated otherwise, all values are taken at room temperature (approximately 20°C or 68°F) and 1 atm pressure. (1 atm = 101,325 Pa)
Related Pages
References: 1) Cardarelli, François. Materials Handbook: A Concise Desktop Reference. Switzerland: Springer International Publishing, 2018. 2) CRC Handbook of Chemistry and Physics, 97th Edition. United Kingdom: CRC Press, 2016-2017. 3) Yaws, Carl L. The Yaws Handbook of Physical Properties for Hydrocarbons and Chemicals. Netherlands: Elsevier Science, 2015. 4) Fire Protection Guide to Hazardous Materials, 14th Edition. United States: National Fire Protection Association, 2010.