Properties of Sulfur Trioxide (SO3)
Sulfur trioxide (SO3) is a chemical compound that is a precursor to sulfuric acid, one of the most important industrial chemicals in the world. It is a colorless to white, fuming solid that is extremely reactive with water. Sulfur trioxide is also a strong oxidizer and can cause severe burns to the skin and eyes.
The following table provides a comprehensive list of sulfur trioxide 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 | 80.064 g/mol |
| Density | 1.92 kg/m3 |
| Dynamic Viscosity (25°C) | 12.9 µPa·s |
| Thermal Properties | Metric |
| Melting Point | 16.8 °C |
| Boiling Point | 44.5 °C |
| Thermal Conductivity (25°C) | 0.011 W/m·K |
| Specific Heat Capacity (Cp) | 632 J/kg·K |
| Critical Constants | Metric |
| Critical Temperature (Tc) | 217.9 °C |
| Critical Pressure (Pc) | 8.2 MPa |
| Critical Density (ρc) | 633 kg/m3 |
| Optical Properties | Metric |
| Refractive Index (589 nm) | 1.000737 |
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.