Properties of Acetylene (C2H2)
Acetylene, also known as ethyne, is a colorless, odorless, and highly flammable hydrocarbon gas with the chemical formula (C2H2). It is widely used in various industrial applications, especially for its ability to produce high-temperature flames when combusted with oxygen.
The following table provides a comprehensive list of acetylene 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 | 26.038 g/mol |
| Density (0°C) | 1.175 kg/m3 |
| Dynamic Viscosity (25°C) | 10.4 µPa·s |
| Speed of Sound in Gas (0°C) | 329 m/s |
| Thermal Properties | Metric |
| Melting Point | -80.7 °C |
| Boiling Point | -84.7 °C |
| Thermal Conductivity (25°C) | 0.0214 W/m·K |
| Specific Heat Capacity (Cp) | 1691 J/kg·K |
| Critical Constants | Metric |
| Critical Temperature (Tc) | 35.25 °C |
| Critical Pressure (Pc) | 6.24 MPa |
| Critical Density (ρc) | 230 kg/m3 |
| Electrical Properties | Metric |
| Relative Permittivity (εr) | 1.00134 |
| Optical Properties | Metric |
| Refractive Index (589 nm) | 1.00061 |
| Hazardous Data | Metric |
| Autoignition Temperature | 305 °C |
| Lower Flammability Limit | 2.5% |
| Upper Flammability Limit | 100% |
| NFPA Rating (Health) | 0 |
| NFPA Rating (Fire) | 4 |
| NFPA Rating (Reactivity) | 3 |
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.