Properties of Sulfur Hexafluoride (SF6)

Sulfur hexafluoride (SF6) is a colorless, odorless, and non-flammable gas known for its high electrical insulating properties. It is commonly used in electrical equipment such as high-voltage circuit breakers, transformers, and switchgear to insulate and extinguish electrical arcs.

The following table provides a comprehensive list of sulfur hexafluoride 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.

Table of Sulfur Hexafluoride Properties
Physical Properties
Metric
Molar Mass146.056 g/mol
Density (0°C)6.516 kg/m3
Dynamic Viscosity (25°C)15.3 µPa·s
Speed of Sound in Gas134 m/s
Thermal PropertiesMetric
Melting Point-50 °C
Boiling Point-63.8 °C
Thermal Conductivity (25°C)0.013 W/m·K
Specific Heat Capacity (Cp)663 J/kg·K
Critical ConstantsMetric
Critical Temperature (Tc)45.6 °C
Critical Pressure (Pc)3.76 MPa
Critical Density (ρc)734 kg/m3
Electrical PropertiesMetric
Relative Permittivity (εr)1.002
Optical PropertiesMetric
Refractive Index (589 nm)1.000783

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)

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.